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#1
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Transformer calculations...
Hi RATs,
I've put together the limit of my knowledge about getting toroidals made for PP output stages. Pat Turner expressed his doubts as to whether I can have them made to spec for the money so I'm running this by you before I use it to spec out a toroidal OT. Of course, the core's going to be 50% oversize... I think it was Phil that suggested having the primaries overwound by 20% but can't remember if he's also meant to calculate the secondaries based on that increase or the original figure... Anyway, here's the calculator - feedback wanted desperately - thanks. Here it is: www.geocities.com/leahsut/trancalc.xls Next thing, I'm calculating the power requirements for the beast... 8xKT88 - for no other reason than I have to out-do an ampeg SVT - yup we're talking bass amps. I'm getting a bit of conflicting information regarding max plate dissipation for kt88's ranging from 42 to52mA So here are my Mains transformer specs so far... 0-400V 400mA (at 50mA) = 160VA - (230VA was closer to what I thought I needed...) 0-6.3V 14A = 90VA 0-50V 0.1A = 5VA Total: 300VA-400VA transformer sufficient cost: $50 - weight= 3.3kg For the OPT, on a 800VA core cost = $80 weight = 5.4kg Something's not quite right IMO. The ampeg has an output power rating of 300W with a 460VA rating on the amp itself so I'd expect to need 600VA for this one which puts the price up $10 and the weight up to 4.4kg. Still, pricing it up: $100 chassis $60 - premade board incl components $160 - valves $100 hardware etc. $150 trannies $50 reserve fund to be drunk if under budget ==== $620 compared with $2400 list... I must be dreaming or what? Thanks cb |
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#2
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Hi Chris,
Have a dream ( or perhaps a nightmare !) In a WELL EARTHED chassis, install your 8 or 10 x KT88. Obtain B+ by direct doubling the mains.(No PST: lightweight). Obtain the filament supply from a 100W switching supply.($100 ?) Add a small tranny for the bias. (or use Zeners in cathodes) Feed the grids from an small inverted PushPull OPT. (Good insulation is a must). Put all that in a cabinet along with 4 heavy speakers. You obtain a 400 / 500 W booster wich can be easily driven by a small Princeton or even a Champion ;) Just for the fun. Anyway, and about the OPT: www.geocities.com/leahsut/trancalc.xls According to this sreadsheet, you will have: 700V accross the total primary (2x350) and, say 6 x 11V secondaries wich could be connected in serie / paralell combinations to approximate the 3 values of load you need. (Remember that loudspeaker impedance may vary by more than 5 times within the audio band). If the Phil's suggestion of 20% overwound is applied, (not sure this be mandatory) that means you must specify: - a 600VA unit, having: - 2 primaries 420V each - 6 secondaries 13V each Insist to have less than 10 Ohms DC resistance for each primry. Still, pricing it up: $100 chassis $60 - premade board incl components $160 - valves $100 hardware etc. $150 trannies $50 reserve fund to be drunk if under budget ==== $620 compared with $2400 list... I must be dreaming or what? An Hammond 280W OPT (eg T1650W) costs already $185 and an (a bit undersized too) PST (eg T378CX) some $125. But we're still below $1000 ! Following incomming path, you may be located somewhere in Germany. Right ? Regards, Yves. Thanks cb |
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#3
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"Yves" wrote in message ... Hi Chris, Have a dream ( or perhaps a nightmare !) In a WELL EARTHED chassis, install your 8 or 10 x KT88. Obtain B+ by direct doubling the mains.(No PST: lightweight). Obtain the filament supply from a 100W switching supply.($100 ?) Add a small tranny for the bias. (or use Zeners in cathodes) Feed the grids from an small inverted PushPull OPT. (Good insulation is a must). Put all that in a cabinet along with 4 heavy speakers. You obtain a 400 / 500 W booster wich can be easily driven by a small Princeton or even a Champion ;) Just for the fun. I thought of doing something similar with an autotransformer. Phil suggested that I would kill myself - and wanted me to test it... Anyway, and about the OPT: www.geocities.com/leahsut/trancalc.xls According to this sreadsheet, you will have: 700V accross the total primary (2x350) and, say 6 x 11V secondaries wich could be connected in serie / paralell combinations to approximate the 3 values of load you need. (Remember that loudspeaker impedance may vary by more than 5 times within the audio band). For the taps, I only need 3 impedances - 3 indings are cheaper than 6.... If the Phil's suggestion of 20% overwound is applied, (not sure this be mandatory) that means you must specify: - a 600VA unit, having: - 2 primaries 420V each - 6 secondaries 13V each Insist to have less than 10 Ohms DC resistance for each primry. It's my spreadsheet btw... so I'm wondering if there are any problems with it.... Still, pricing it up: $100 chassis $60 - premade board incl components $160 - valves $100 hardware etc. $150 trannies $50 reserve fund to be drunk if under budget ==== $620 compared with $2400 list... I must be dreaming or what? An Hammond 280W OPT (eg T1650W) costs already $185 and an (a bit undersized too) PST (eg T378CX) some $125. But we're still below $1000 ! www.multi-pcb.de insists they'll do a good job and to my spec at 50% of the hammond cost.... what have I to lose? Following incomming path, you may be located somewhere in Germany. Right ? Yup - well for the next hour or so - will be in Luxembourg after that... You in France? Played a lot of Rugby there... cb |
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#4
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"Chris Berry" a écrit dans le message de news: ... [ . . .] Next thing, I'm calculating the power requirements for the beast... 8xKT88 - for no other reason than I have to out-do an ampeg SVT - yup we're talking bass amps. I'm getting a bit of conflicting information regarding max plate dissipation for kt88's ranging from 42 to52mA KT88 data sheet says 60mA per tube at idle, BUT 145mA at full power, So, 0.145 x 8 = 1.16A at 550V = 640W. [ . . . ] Yves. |
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#5
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"Chris Berry" a écrit dans le message de news: ... "Yves" wrote in message ... Hi Chris, Have a dream ( or perhaps a nightmare !) In a WELL EARTHED chassis, install your 8 or 10 x KT88. Obtain B+ by direct doubling the mains.(No PST: lightweight). Obtain the filament supply from a 100W switching supply.($100 ?) Add a small tranny for the bias. (or use Zeners in cathodes) Feed the grids from an small inverted PushPull OPT. (Good insulation is a must). Put all that in a cabinet along with 4 heavy speakers. You obtain a 400 / 500 W booster wich can be easily driven by a small Princeton or even a Champion ;) Just for the fun. I thought of doing something similar with an autotransformer. Phil suggested that I would kill myself - and wanted me to test it... Anyway, such a project, with or without power tranny IS a killer ! Anyway, and about the OPT: www.geocities.com/leahsut/trancalc.xls According to this sreadsheet, you will have: 700V accross the total primary (2x350) and, say 6 x 11V secondaries wich could be connected in serie / paralell combinations to approximate the 3 values of load you need. (Remember that loudspeaker impedance may vary by more than 5 times within the audio band). For the taps, I only need 3 impedances - 3 indings are cheaper than 6.... Yes, but so you'll never have unused windings, and, at the final, less copper. If the Phil's suggestion of 20% overwound is applied, (not sure this be mandatory) that means you must specify: - a 600VA unit, having: - 2 primaries 420V each - 6 secondaries 13V each Insist to have less than 10 Ohms DC resistance for each primry. It's my spreadsheet btw... so I'm wondering if there are any problems with it.... I think it's right. If you're interresested to go a bit deeper, download a tool I've wrote at http://geek.scorpiorising.ca/ Unfortunatly, it does not cover the use of toroids cos have no data about. Still, pricing it up: $100 chassis $60 - premade board incl components $160 - valves $100 hardware etc. $150 trannies $50 reserve fund to be drunk if under budget ==== $620 compared with $2400 list... I must be dreaming or what? An Hammond 280W OPT (eg T1650W) costs already $185 and an (a bit undersized too) PST (eg T378CX) some $125. But we're still below $1000 ! www.multi-pcb.de insists they'll do a good job and to my spec at 50% of the hammond cost.... what have I to lose? Following incomming path, you may be located somewhere in Germany. Right ? Yup - well for the next hour or so - will be in Luxembourg after that... You in France? Played a lot of Rugby there... South of France, nearest Rugby club is "LaVoulte" where Camberaberos brothers played. cb |
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#6
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Chris Berry wrote: Hi RATs, I've put together the limit of my knowledge about getting toroidals made for PP output stages. Pat Turner expressed his doubts as to whether I can have them made to spec for the money so I'm running this by you before I use it to spec out a toroidal OT. I did express some doubts about obtaining a decently custom wound toroidal with two 240volt "primaries", one for each half of the OPT PP primary, I also said that to do it right, a total of four 240v primaries should be used, so that the core saturation would not occur until 20 Hz was reached. For an AB bass amp, a typical B+ would be 550v, and the load would be about 1.4 k anode to anode, allowing the production of about 636 vrms anode to anode, which is 289 watts. Most mains windings on toroidal cores run at 1.2 Tesla at 50 Hz, so to get decent performance at bass F, you need twice the turns to achieve 1.2 Tesla at 25 Hz. So having 2 windings of 240v in series means the tranny will still have 1.2 Tesla at 50 Hz at 480 vrms. To have 1.2T at 25 Hz demands 4 x 240v windings. However, full saturation occurs at more like 1.8 Tesla, so the 4 x 240 v windings would be good for 480 v at 16.6 Hz, of if we settled for 700 v anode to anode with a high value load, then we'd have 1.8 T and saturation at 24 Hz. If you are considering 120v primaries, you would need 8 of them in series to get anywhere. The secondaries should be all wound at least in the middle between the two halves of the primary winding. It does not matter if you had a mains core rated at 1 kW, you would still need 4 x 240 volt windings, or 8 x 120 volt windings to be able to use the tranny in a 300 watt tube amp. The output transformer needs to be desinged for winding losses of 5%, so this means the DCR of the P winding is 2.5% of 1,400 ohms, or 35 ohms, and the DRC of the sec is 2.5% of 8 ohms, or 0.2 ohms. There is no benefit in asking a winder to lay on 4 x 240v primaries for mains as he would on a 300 VA core. Such a winding has a current ability of 300 /240 = 1.25 amps, so the input load is 240 / 1.25 = 192 ohms, so the DCR would be 2.5% of 192 = 4.8 ohms. 4 such windings won't fit on a 300 VA core. And the DCR woulod be 19.2 ohms, and too low for what we want. So we would use the same turns, but with a resistance of 35 ohms, so the wire dia can be 0.7 of the normal size used for the mains. To make sure the turns would fit, we'd use a bigger toroid with a higher VA rating, say 500 VA. Unless a specialist winder knows all about frequency response and saturation, and has the best the interests of the audio amateur in his mind, then he might wind you up a dud, or something very nearly equal to or worse than the worst quality imaginable! Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. Of course, the core's going to be 50% oversize... I think it was Phil that suggested having the primaries overwound by 20% but can't remember if he's also meant to calculate the secondaries based on that increase or the original figure... Anyway, here's the calculator - feedback wanted desperately - thanks. Here it is: www.geocities.com/leahsut/trancalc.xls Next thing, I'm calculating the power requirements for the beast... 8xKT88 - for no other reason than I have to out-do an ampeg SVT - yup we're talking bass amps. I'm getting a bit of conflicting information regarding max plate dissipation for kt88's ranging from 42 to52mA So here are my Mains transformer specs so far... 0-400V 400mA (at 50mA) = 160VA - (230VA was closer to what I thought I needed...) 0-6.3V 14A = 90VA 0-50V 0.1A = 5VA Total: 300VA-400VA transformer sufficient cost: $50 - weight= 3.3kg For the OPT, on a 800VA core cost = $80 weight = 5.4kg Something's not quite right IMO. The ampeg has an output power rating of 300W with a 460VA rating on the amp itself so I'd expect to need 600VA for this one which puts the price up $10 and the weight up to 4.4kg. Still, pricing it up: $100 chassis $60 - premade board incl components $160 - valves $100 hardware etc. $150 trannies $50 reserve fund to be drunk if under budget ==== $620 I wish you the best of luck with your project. I somehow think that you'd need to be able to better spell out *all* the design details or else you will surely use up the drinking allowance of $50, and it won't be due to coming home under budget. Patrick Turner. compared with $2400 list... I must be dreaming or what? Thanks cb |
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#7
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"Patrick Turner" I did express some doubts about obtaining a decently custom wound toroidal with two 240volt "primaries", one for each half of the OPT PP primary, I also said that to do it right, a total of four 240v primaries should be used, so that the core saturation would not occur until 20 Hz was reached. ** So the Turneroid who knows SFall knows how to " do it right " does he ??? Has he ever even seen an Ampeg SVT ????? Or any other bass guitar head for that matter ??? Or is he just regurgitating rote learnt tracts from the RDH4 as per usual ?? Most mains windings on toroidal cores run at 1.2 Tesla at 50 Hz, so to get decent performance at bass F, you need twice the turns to achieve 1.2 Tesla at 25 Hz. ** You can all see how the Turneroid ignores all and any factual information about the REAL WORLD so that his rote learnt tracts from the RDH4 can be trotted out as holy gospel on every possible occasion - in parrot fashion. A featherless, squawking, demented parrot at that. The secondaries should be all wound at least in the middle between the two halves of the primary winding. ** Why is that Mr Turneroid ?? - so the response goes out to 300 kHz ???? In the REAL WORLD a bass guitar amp needs response out to 7 or 8 kHz - at most. In the REAL WORLD a bass guitar amp has full power available down to 50 z - if it is a very good one. The output transformer needs to be designed for winding losses of 5%, ** Which page of the RDH4 is that one on Pat ?? The Turneroid must have committed the whole damn paper anachronism to memory - like those living books in " Fahrenheit 451 " Unless a specialist winder knows all about frequency response and saturation, and has the best the interests of the audio amateur in his mind, then he might wind you up a dud, or something very nearly equal to or worse than the worst quality imaginable! ** The guy wants to make himself a bass GUITAR amp for Christs sake !!! He is not a tube amp fetishist like the Turneroid. Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. ** In particular, the Turneroid has *no idea* of the required details. So to cover up his ignorance of the topic and head off ridicule he resorts to regurgitating rote learnt tracts from his " tube boob's bible " - then spews them out al over the place here while posturing as a tube amp sage. The *pathetic* things a geriatric builder gets up to on a NG - eh ? ............. Phil |
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#8
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Phil Allison wrote: "Patrick Turner" I did express some doubts about obtaining a decently custom wound toroidal with two 240volt "primaries", one for each half of the OPT PP primary, I also said that to do it right, a total of four 240v primaries should be used, so that the core saturation would not occur until 20 Hz was reached. ** So the Turneroid who knows SFall knows how to " do it right " does he ??? Has he ever even seen an Ampeg SVT ????? No, and I don't need to in this case, to be able to express an opinion. Or any other bass guitar head for that matter ??? WTF have any othe bass heads got to do with the original poster's concerns, ot things I mentioned *should* be his concerns? Or is he just regurgitating rote learnt tracts from the RDH4 as per usual ?? I never mentioned RDH4 once. Most mains windings on toroidal cores run at 1.2 Tesla at 50 Hz, so to get decent performance at bass F, you need twice the turns to achieve 1.2 Tesla at 25 Hz. ** You can all see how the Turneroid ignores all and any factual information about the REAL WORLD so that his rote learnt tracts from the RDH4 can be trotted out as holy gospel on every possible occasion - in parrot fashion. A featherless, squawking, demented parrot at that. But unfortunately for you, not a dead parrot. With a very sharp beak to peck your arguments to peices. The secondaries should be all wound at least in the middle between the two halves of the primary winding. ** Why is that Mr Turneroid ?? - so the response goes out to 300 kHz ???? I know, but you obviously don't. In the REAL WORLD a bass guitar amp needs response out to 7 or 8 kHz - at most. Then an ordinary E&I tranny will do..... In the REAL WORLD a bass guitar amp has full power available down to 50 z - if it is a very good one. So what happens below 50Hz? Phil approves of borderline designs which don't allow some slight margin to keep away from saturation at full power, which is used very often deliberately by musos. The output transformer needs to be designed for winding losses of 5%, ** Which page of the RDH4 is that one on Pat ?? I haven't a clue, you tell the group. But the P has 2.5%, and the S has 2.5%, then the total losses are 5%. there are many OPTs with 10% winding losses, but why waste power in the tranny if its easily possible to get the losses down to 5% because we have the room on a suitable toroidal core to get enough copper on to keep losses low? The Turneroid must have committed the whole damn paper anachronism to memory - like those living books in " Fahrenheit 451 " Meanwhile, all Phil can remember is the high marks he scored at uni in 1972 for the subject " Contributing FA to design theory " Unless a specialist winder knows all about frequency response and saturation, and has the best the interests of the audio amateur in his mind, then he might wind you up a dud, or something very nearly equal to or worse than the worst quality imaginable! ** The guy wants to make himself a bass GUITAR amp for Christs sake !!! That's right, indeed he does, and he ought to do it right, or not at all, as far as I am concerned. He is welcome to ignore me, it's everyone's option. But we know you can't, and I really don't give a rat's arse if you cannot come up with a fully spelt out exact design which allows slightly greater bandwidth. If ever the amp we sold to someone wanting wider BW, they'd have it. Meanwhile, if the bass guitarist wants only 8 kHz, no problem, an RC filter on the input does the trick. But guitarists are notorious for turning up the presence, and the treble boost; every darn thing that can be turned up is turned up, to the point where the upper harmonics overload the amp before the LF tones. He is not a tube amp fetishist like the Turneroid. What are you doing in this newsgroup? Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. ** In particular, the Turneroid has *no idea* of the required details. But I did point out the main ones on turns and saturation concerns, and you certainly have failed miserably to address the issues I have raised. So to cover up his ignorance of the topic and head off ridicule he resorts to regurgitating rote learnt tracts from his " tube boob's bible " - then spews them out al over the place here while posturing as a tube amp sage. Ah, so you think the Radiotron Designer's Handbook is a pile of ****e? I see how you must "think"; it must be wrong, it is so old, about 50 now, hell, never trust an old book; why, you'll be led astray real quick. What the F did all those old farts know back in 1952? A boody sight more than Phil Allison knows!!!! The *pathetic* things a geriatric builder gets up to on a NG - eh ? ............ Phil Phil Allison never builds any tube amps, he trots around the web on his donkey charging at windmills, and cannot tender any sensible recipes unless goaded with 10 rude posts, and only then does he ever try to be constructive. He hates giving knowledge out freely, and treats everyone as morons, but we all know he got a 1972 Degree in Moronogy. He cannot win arguments with me, so he resorts to personal insult which is a pattern of behaviour they really disapprove of at universities, where they teach ppl to stay with what they understand as facts at all times. Maybe they gave him the degree he claims to have got just to get rid of the *******. What has Phil Allison contributed to the design of transformers here? Absolutely SFA. Where has he properly and fully quoted my post, and carefully demolished my arguments? Not here today folks. Phil Allison is incapable of detailed argument, and should go **** off to some other news group where they enjoy being savaged by banalities. I have little more to contribute on the subject because I went through all the same details some time ago. Patrick Turner. |
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#9
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"Patrick Turner" Phil Allison wrote: ** So the Turneroid who knows SFall knows how to " do it right " does he ??? Has he ever even seen an Ampeg SVT ????? No, and I don't need to in this case, to be able to express an opinion. ** So the Turneroid Parrott admits his "opinion" is ill informed on the matter. But he is, nevertheless, hell bent on shoving it down people's throats. Or any other bass guitar head for that matter ??? WTF have any othe bass heads got to do with the original poster's concerns, ot things I mentioned *should* be his concerns ** The OP seems to be building a bass head for himself - not inventing the beast. Someone with no experience of their design has no basis for giving lectures - but that will never stop a rote learnt bigot. Or is he just regurgitating rote learnt tracts from the RDH4 as per usual ?? I never mentioned RDH4 once. ** No need to mention it - the Turneroid Parrott has absorbed it all verbatim. ** You can all see how the Turneroid ignores all and any factual information about the REAL WORLD so that his rote learnt tracts from the RDH4 can be trotted out as holy gospel on every possible occasion - in parrot fashion. A featherless, squawking, demented parrot at that. But unfortunately for you, not a dead parrot. With a very sharp beak to peck your arguments to peices. ** As you can see, the Turneroid Parrott suffers from some severe delusions. The secondaries should be all wound at least in the middle between the two halves of the primary winding. ** Why is that Mr Turneroid ?? - so the response goes out to 300 kHz ???? I know, but you obviously don't. ** Yes I do. RDH4 says it must be done that way. So then does the Turneroid Parrott - ad infinitum - ad nauseam. In the REAL WORLD a bass guitar amp needs response out to 7 or 8 Hz - at most. Then an ordinary E&I tranny will do..... ** Never in dispute - and is what all commercial bass amps use. The proposition is that a basic toroidal will be far cheaper as a one off. In the REAL WORLD a bass guitar amp has full power available down to 50 z - if it is a very good one. So what happens below 50Hz? ** The Turneroid Parrott would never dream of getting a bass guitar and finding out. Phil approves of borderline designs which don't allow some slight margin to keep away from saturation at full power, which is used very often deliberately by musos. ** An Ampeg SVT is no borderline design - but the the Turneroid Parrott has never seen one so cannot say. The output transformer needs to be designed for winding losses of 5%, ** Which page of the RDH4 is that one on Pat ?? I haven't a clue, you tell the group. ** Now the Turneroid Parrott is playing dumb - a role that comes very readily. The Turneroid must have committed the whole damn paper anachronism to memory - like those living books in " Fahrenheit 451 " Meanwhile, all Phil can remember is the high marks he scored at uni in 1972 for the subject " Contributing FA to design theory " ** The Turneroid Parrott possess no design theory to give anyone - just rote learnt tracts from his RDH4 bible. ** The guy wants to make himself a bass GUITAR amp for Christs sake !!! That's right, indeed he does, and he ought to do it right, or not at all, as far as I am concerned. ** But the Turneroid Parrott has NO IDEA what "right " is in the matter. He is welcome to ignore me, it's everyone's option. ** I am giving him a few ***damn good reasons*** to do just that. If ever the amp we sold to someone wanting wider BW, they'd have it. ** The Turneroid Parrott has NO IDEA what the term "overdesigned" means. Meanwhile, if the bass guitarist wants only 8 kHz, no problem, an RC filter on the input does the trick. ** The Turneroid Parrott has failed to see how absurd that comment is in light of his recipe for a layer wound toroidal transformer. But guitarists are notorious for turning up the presence, and the treble boost; every darn thing that can be turned up is turned up, to the point where the upper harmonics overload the amp before the LF tones. ** The Turneroid Parrott has forgotten the amp is for a bass guitar. He is not a tube amp fetishist like the Turneroid. What are you doing in this newsgroup? ** The Turneroid Parrott thinks this NG is called "rec.audio.tube-fetishist". Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. ** In particular, the Turneroid has *no idea* of the required details. But I did point out the main ones on turns and saturation concerns, ** The Turneroid Parrott has no idea what the real concerns are - as they are not described in his RDH4 bible. and you certainly have failed miserably to address the issues I have raised. ** The Turneroid Parrott has only spewed out his rote learnt RDH4 ecipes - none of which are for cooking up a bass guitar amp. So to cover up his ignorance of the topic and head off ridicule he resorts to regurgitating rote learnt tracts from his " tube boob's bible " - then spews them out al over the place here while posturing as a tube amp sage. Ah, so you think the Radiotron Designer's Handbook is a pile of ****e? ** The Turnerpoid parrot has nothing else to refer to so is desperate to pretend RDH4 is the *holy bible* on ALL tube amp matters. I see how you must "think"; it must be wrong, ** RDH4 is not wrong - the Turneroid Parrott is WRONG to quote from it where it does not apply. A boody sight more than Phil Allison knows!!!! ** The Turneroid Parrott is a ONE BOOK BIGOT - just like some mad bible basher. What has Phil Allison contributed to the design of transformers here? Absolutely SFA. ** The Turneroid parrot is unable to see any good in something that did not come from the RDH4. A one book bigot is all he is. This NG is the bigot's pulpit where he delivers his rabid sermons on Parrott Logic. Where has he properly and fully quoted my post, and carefully demolished my arguments? ** The Turneroid Parrott has posted no rational arguments - he is after all just a parrott and cannot think. I have little more to contribute on the subject because I went through all the same details some time ago. ** The Turneroid Parrot is a parrott - he just says the same stupid things over and over and over and over ..... ............ Phil |
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#10
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I have ZERO intention of replying to the
litany of personal insults and technical misconceptions in Phil Allison's post below. Readers are well advised to move right alone to the next readable post by somebody else. Patrick Turner. Phil Allison wrote: "Patrick Turner" Phil Allison wrote: ** So the Turneroid who knows SFall knows how to " do it right " does he ??? Has he ever even seen an Ampeg SVT ????? No, and I don't need to in this case, to be able to express an opinion. ** So the Turneroid Parrott admits his "opinion" is ill informed on the matter. But he is, nevertheless, hell bent on shoving it down people's throats. Or any other bass guitar head for that matter ??? WTF have any othe bass heads got to do with the original poster's concerns, ot things I mentioned *should* be his concerns ** The OP seems to be building a bass head for himself - not inventing the beast. Someone with no experience of their design has no basis for giving lectures - but that will never stop a rote learnt bigot. Or is he just regurgitating rote learnt tracts from the RDH4 as per usual ?? I never mentioned RDH4 once. ** No need to mention it - the Turneroid Parrott has absorbed it all verbatim. ** You can all see how the Turneroid ignores all and any factual information about the REAL WORLD so that his rote learnt tracts from the RDH4 can be trotted out as holy gospel on every possible occasion - in parrot fashion. A featherless, squawking, demented parrot at that. But unfortunately for you, not a dead parrot. With a very sharp beak to peck your arguments to peices. ** As you can see, the Turneroid Parrott suffers from some severe delusions. The secondaries should be all wound at least in the middle between the two halves of the primary winding. ** Why is that Mr Turneroid ?? - so the response goes out to 300 kHz ???? I know, but you obviously don't. ** Yes I do. RDH4 says it must be done that way. So then does the Turneroid Parrott - ad infinitum - ad nauseam. In the REAL WORLD a bass guitar amp needs response out to 7 or 8 Hz - at most. Then an ordinary E&I tranny will do..... ** Never in dispute - and is what all commercial bass amps use. The proposition is that a basic toroidal will be far cheaper as a one off. In the REAL WORLD a bass guitar amp has full power available down to 50 z - if it is a very good one. So what happens below 50Hz? ** The Turneroid Parrott would never dream of getting a bass guitar and finding out. Phil approves of borderline designs which don't allow some slight margin to keep away from saturation at full power, which is used very often deliberately by musos. ** An Ampeg SVT is no borderline design - but the the Turneroid Parrott has never seen one so cannot say. The output transformer needs to be designed for winding losses of 5%, ** Which page of the RDH4 is that one on Pat ?? I haven't a clue, you tell the group. ** Now the Turneroid Parrott is playing dumb - a role that comes very readily. The Turneroid must have committed the whole damn paper anachronism to memory - like those living books in " Fahrenheit 451 " Meanwhile, all Phil can remember is the high marks he scored at uni in 1972 for the subject " Contributing FA to design theory " ** The Turneroid Parrott possess no design theory to give anyone - just rote learnt tracts from his RDH4 bible. ** The guy wants to make himself a bass GUITAR amp for Christs sake !!! That's right, indeed he does, and he ought to do it right, or not at all, as far as I am concerned. ** But the Turneroid Parrott has NO IDEA what "right " is in the matter. He is welcome to ignore me, it's everyone's option. ** I am giving him a few ***damn good reasons*** to do just that. If ever the amp we sold to someone wanting wider BW, they'd have it. ** The Turneroid Parrott has NO IDEA what the term "overdesigned" means. Meanwhile, if the bass guitarist wants only 8 kHz, no problem, an RC filter on the input does the trick. ** The Turneroid Parrott has failed to see how absurd that comment is in light of his recipe for a layer wound toroidal transformer. But guitarists are notorious for turning up the presence, and the treble boost; every darn thing that can be turned up is turned up, to the point where the upper harmonics overload the amp before the LF tones. ** The Turneroid Parrott has forgotten the amp is for a bass guitar. He is not a tube amp fetishist like the Turneroid. What are you doing in this newsgroup? ** The Turneroid Parrott thinks this NG is called "rec.audio.tube-fetishist". Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. ** In particular, the Turneroid has *no idea* of the required details. But I did point out the main ones on turns and saturation concerns, ** The Turneroid Parrott has no idea what the real concerns are - as they are not described in his RDH4 bible. and you certainly have failed miserably to address the issues I have raised. ** The Turneroid Parrott has only spewed out his rote learnt RDH4 ecipes - none of which are for cooking up a bass guitar amp. So to cover up his ignorance of the topic and head off ridicule he resorts to regurgitating rote learnt tracts from his " tube boob's bible " - then spews them out al over the place here while posturing as a tube amp sage. Ah, so you think the Radiotron Designer's Handbook is a pile of ****e? ** The Turnerpoid parrot has nothing else to refer to so is desperate to pretend RDH4 is the *holy bible* on ALL tube amp matters. I see how you must "think"; it must be wrong, ** RDH4 is not wrong - the Turneroid Parrott is WRONG to quote from it where it does not apply. A boody sight more than Phil Allison knows!!!! ** The Turneroid Parrott is a ONE BOOK BIGOT - just like some mad bible basher. What has Phil Allison contributed to the design of transformers here? Absolutely SFA. ** The Turneroid parrot is unable to see any good in something that did not come from the RDH4. A one book bigot is all he is. This NG is the bigot's pulpit where he delivers his rabid sermons on Parrott Logic. Where has he properly and fully quoted my post, and carefully demolished my arguments? ** The Turneroid Parrott has posted no rational arguments - he is after all just a parrott and cannot think. I have little more to contribute on the subject because I went through all the same details some time ago. ** The Turneroid Parrot is a parrott - he just says the same stupid things over and over and over and over ..... ........... Phil |
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"Patrick Turner" I have ZERO intention of replying to the litany of personal insults and technical misconceptions in Phil Allison's post below. ** So the Turneroid Parrot is lost for words is he ?? More like he is shying away from the simple truth. Readers are well advised to move right alone to the next readable post by somebody else. ** Best avoid those from one book bigots and squawking, featherless parrots. ............. Phil |
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#12
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"Patrick Turner" wrote in message ... I did express some doubts about obtaining a decently custom wound toroidal with two 240volt "primaries", one for each half of the OPT PP primary, I also said that to do it right, a total of four 240v primaries should be used, so that the core saturation would not occur until 20 Hz was reached. For an AB bass amp, a typical B+ would be 550v, and the load would be about 1.4 k anode to anode, allowing the production of about 636 vrms anode to anode, which is 289 watts. Most mains windings on toroidal cores run at 1.2 Tesla at 50 Hz, so to get decent performance at bass F, you need twice the turns to achieve 1.2 Tesla at 25 Hz. So having 2 windings of 240v in series means the tranny will still have 1.2 Tesla at 50 Hz at 480 vrms. To have 1.2T at 25 Hz demands 4 x 240v windings. Is there any way of calculating the magnetic density at full power (I think this is the Tesla you're refering to) and for different frequencies? My winder (the company) allows me to specify the operating frequency (probably for their calculation) but this might be useful knowing how appropriate the 1.2T is at 50Hz... then running some other spec by them. However, full saturation occurs at more like 1.8 Tesla, so the 4 x 240 v windings would be good for 480 v at 16.6 Hz, of if we settled for 700 v anode to anode with a high value load, then we'd have 1.8 T and saturation at 24 Hz. As Phil stated (in his usual style) you probably only need 40Hz at -3dB - better would be at -1dB or less agreed but it's certainly not "necessary". 3dB headroom @50Hz should be enough and good for a full bass sound (as opposed to a good bass sound in terms of reproduction) a core of 50% greater VA won't produce this however but looking at the harmonic content of bass, about 50% of the power of the lowest notes is likely to be in the sub 50Hz range. Looking at what you guys are saying though, it looks like rating the entire transformer at 50%-100% over the calculated minimum values is likely to be my best bet - and use a bigger core than even that allows. If you are considering 120v primaries, you would need 8 of them in series to get anywhere. The secondaries should be all wound at least in the middle between the two halves of the primary winding. It does not matter if you had a mains core rated at 1 kW, you would still need 4 x 240 volt windings, or 8 x 120 volt windings to be able to use the tranny in a 300 watt tube amp. I don't think this applies with respect to my winder... they will wind any primaries needed - also not as multiples of 240V - up to 800Volts. e.g. before losses, an 800W transformer (500 - 0 - 500 primary) to use on a 400W amp shouldn't be a problem (although they'll have to wind 2 identical 500V primaries that I'll have to wire together for the center tap... The output transformer needs to be desinged for winding losses of 5%, so this means the DCR of the P winding is 2.5% of 1,400 ohms, or 35 ohms, Ah OK so a max DCR spec should be added at 2.5% of the impedances. and the DRC of the sec is 2.5% of 8 ohms, or 0.2 ohms. There is no benefit in asking a winder to lay on 4 x 240v primaries for mains as he would on a 300 VA core. Such a winding has a current ability of 300 /240 = 1.25 amps, so the input load is 240 / 1.25 = 192 ohms, so the DCR would be 2.5% of 192 = 4.8 ohms. 4 such windings won't fit on a 300 VA core. And the DCR woulod be 19.2 ohms, and too low for what we want. So we would use the same turns, but with a resistance of 35 ohms, so the wire dia can be 0.7 of the normal size used for the mains. To make sure the turns would fit, we'd use a bigger toroid with a higher VA rating, say 500 VA. Are you saying we actually want or need those 5% losses? or it's good to have 5% per side? or that they need to be the same? Unless a specialist winder knows all about frequency response and saturation, and has the best the interests of the audio amateur in his mind, then he might wind you up a dud, or something very nearly equal to or worse than the worst quality imaginable! I think this is where Phil's argument comes in. For bass guitar, you're not really too interested in anything much above 5-7kHz - well the speakers and instrument can't normally produce that anyway so it's a slightly different ballgame to hifi/PA. Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. Maybe we can remedy that a little by putting a bit of knowledge together so that we can have half decent toroids at really low prices. Perhaps a little on winding technique, little on frequency response, desired magnetic flux, wire specs, impedance matching and whatnot.. it would be good no? I wish you the best of luck with your project. I somehow think that you'd need to be able to better spell out *all* the design details or else you will surely use up the drinking allowance of $50, and it won't be due to coming home under budget. Thanks Pat. Yup the devil's in the planning and detail as always but with a little help from my friends... maybe it's possible to have the drinking budget shared... cb |
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#13
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#14
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Chris Berry wrote: "Patrick Turner" wrote in message ... I did express some doubts about obtaining a decently custom wound toroidal with two 240volt "primaries", one for each half of the OPT PP primary, I also said that to do it right, a total of four 240v primaries should be used, so that the core saturation would not occur until 20 Hz was reached. For an AB bass amp, a typical B+ would be 550v, and the load would be about 1.4 k anode to anode, allowing the production of about 636 vrms anode to anode, which is 289 watts. Most mains windings on toroidal cores run at 1.2 Tesla at 50 Hz, so to get decent performance at bass F, you need twice the turns to achieve 1.2 Tesla at 25 Hz. So having 2 windings of 240v in series means the tranny will still have 1.2 Tesla at 50 Hz at 480 vrms. To have 1.2T at 25 Hz demands 4 x 240v windings. Is there any way of calculating the magnetic density at full power (I think this is the Tesla you're refering to) and for different frequencies? Yes, go to my webpages at http://www.turneraudio.com.au/htmlwe...utputtrans.htm and follow the leads and links. For the novice, its rather difficult to follow wtf I am saying at the website, and you also should refer to the text books on electro magnetics to have a better idea. See http://www.turneraudio.com.au/htmlwe...esigncalcs.htm See steps 1 onwards to how to design an output transformer, type No 1. This is an E&I transformer good for hi-fi and 60 watts, but the prinicples for a 300 watt tranny are the same. I do not have anything on toroidal designs, but the winding numbers, and core section relationship is the same, and described by the formula :- 22.6 x V x 10,000 Fs = -------------------- B x Np x Afe Where, Fs = frequency of saturation, 22.6 is a constant for all equations, V = voltage in rms across the primary, Np = primary turns, B = maximum magnetic field strength in Tesla in the core, Afe = cross sectional area of the central core leg, in square mm. My winder (the company) allows me to specify the operating frequency (probably for their calculation) but this might be useful knowing how appropriate the 1.2T is at 50Hz... then running some other spec by them. Well if the B max is allowed to be as high as 1.5T, and the F at which 1,5T occurs is at say 25 Hz, they should be putting 4 times the turns of a normal 240v winding to give a 700 vrms capability. However, full saturation occurs at more like 1.8 Tesla, so the 4 x 240 v windings would be good for 480 v at 16.6 Hz, of if we settled for 700 v anode to anode with a high value load, then we'd have 1.8 T and saturation at 24 Hz. As Phil stated (in his usual style) you probably only need 40Hz at -3dB - better would be at -1dB or less agreed but it's certainly not "necessary". You will not measure the -3 dB point where the value of inductance of the primary causes a 3 dB drop in amp gain at full power. The core will saturate, ie, the winding will become a short circuit to current for part of the cycle when the iron refuses to magnetise any further than it can. To avoid this effect at too high an F, more turns are used. You'd think that more turns would cause more problems, but the common sense approach with electro magnetics is a futile way to try to understand, you need to study on a higher level to know why it is so. 3dB headroom @50Hz should be enough and good for a full bass sound (as opposed to a good bass sound in terms of reproduction) a core of 50% greater VA won't produce this however but looking at the harmonic content of bass, about 50% of the power of the lowest notes is likely to be in the sub 50Hz range. Nope, very litle content theoretically exists lower than the E string on a bass, which is at about 80 Hz. But LF transients do occur, and its best to make the tranny to have a wider range ability. Looking at what you guys are saying though, it looks like rating the entire transformer at 50%-100% over the calculated minimum values is likely to be my best bet - and use a bigger core than even that allows. Its just not a simple matter of making a bigger VA tranny. Even if you used a 2 Kw mains tranny, you still need more turns than two 240 volt windings. As the VA rating and core size increases, less turn per volt are used, and the B stays put. If you are considering 120v primaries, you would need 8 of them in series to get anywhere. The secondaries should be all wound at least in the middle between the two halves of the primary winding. It does not matter if you had a mains core rated at 1 kW, you would still need 4 x 240 volt windings, or 8 x 120 volt windings to be able to use the tranny in a 300 watt tube amp. I don't think this applies with respect to my winder... they will wind any primaries needed - also not as multiples of 240V - up to 800Volts. e.g. before losses, an 800W transformer (500 - 0 - 500 primary) to use on a 400W amp shouldn't be a problem (although they'll have to wind 2 identical 500V primaries that I'll have to wire together for the center tap... You don't need a 1,000 vrms capability. You do need 350-0-350 capability, ie, 700vrms across the P The DCR need only be 2.5% of the primay load of around 1.4k, so 35 ohms will be fine. The winder should work out the turns so where F = 25 Hz, B = 1.5 Tesla, and V = 700 vrms. The core should have a 500 VA rating. When the turns are worked out for the P, the turns for the secondary can be calculated. 350 watts into 8 ohms is 53 vrms, so the P : S turn ratio of the tranny will be around 700 : 53. The secondary can be one layer all around the core using wire whose DCR will be no more than 2.5% of 8 ohms, ie, 0.2 ohms. It will be quite thick wire, and if the diameter of the hole is 50 mm, then the circumferance is about 140mm, allowing for the sec to be placed after half the primary turns. I have no clue as to what sized core section the winder mat have, but suppose there were to be 1,200 turns for the P, then you'd need 90 turns for the sec, and the overall wire dia for the S should be 140 / 90 = 1.55, so perhaps 1.5mm copper dia wire could be used, if the DCR is low enough. 53 v into 8 ohms is 6.6 amps rms, and you should allow 2.5 amps per sq.mm for the wire, so 2.65 sq.mm is needed, and 1.5mm dia is only 1.77 sq.mm, and I bet the DCR of the sec well exceeds 0.2 ohms. The sec may have to be two over lapping layers of say 1.2mm dia wire, with each winding in parallel. Without knowing all the core dimensions, I cannot work out for you what your winder should be able to do. If the winder don't understand *all* this, he should be selling meat pies at a circus. The output transformer needs to be desinged for winding losses of 5%, so this means the DCR of the P winding is 2.5% of 1,400 ohms, or 35 ohms, Ah OK so a max DCR spec should be added at 2.5% of the impedances. Nope. The 2.5% losses are of each P and S winding so you get 5% total winding losses. The model of a transfornmer is one where the transformer is a perfect winding, and where the DCR of the windings appear in series with each winding. The low DCR of the sec is seen by the tubes as the impedance ratio x by the sec DCR. This is the "reflected resistance" of the secondary. The total impedance seen by the tubes is the DCR opf the P plus the reflected DCR of the S. The output tubes see the calculated RL plus the total DCR in series, so if the RL = 1,400 ohms, and P losses = S losses of 35 ohms each seen at the input to the P, then the load total seen is 1,470 ohms. and the DRC of the sec is 2.5% of 8 ohms, or 0.2 ohms. There is no benefit in asking a winder to lay on 4 x 240v primaries for mains as he would on a 300 VA core. Such a winding has a current ability of 300 /240 = 1.25 amps, so the input load is 240 / 1.25 = 192 ohms, so the DCR would be 2.5% of 192 = 4.8 ohms. 4 such windings won't fit on a 300 VA core. And the DCR woulod be 19.2 ohms, and too low for what we want. So we would use the same turns, but with a resistance of 35 ohms, so the wire dia can be 0.7 of the normal size used for the mains. To make sure the turns would fit, we'd use a bigger toroid with a higher VA rating, say 500 VA. Are you saying we actually want or need those 5% losses? or it's good to have 5% per side? or that they need to be the same? Both P and S windings should have equal % losses, and the rise in temperature is equal. 5% of 300 watts is 15 watts. The average power level with music is a lot lower than a sine wave at 300 watts, so OPTs only ever run slightly warm even if total losses are 10%. Unless a specialist winder knows all about frequency response and saturation, and has the best the interests of the audio amateur in his mind, then he might wind you up a dud, or something very nearly equal to or worse than the worst quality imaginable! I think this is where Phil's argument comes in. For bass guitar, you're not really too interested in anything much above 5-7kHz - well the speakers and instrument can't normally produce that anyway so it's a slightly different ballgame to hifi/PA. Nearly all the guitar amps I test are good to about 12 kHz. The toroidal as suggested will give you more than what is needed, but that is a bonus, and having equal P halves either side of the sec is easy to do. With an E&I tranny, there would have to be only 3 P sections of primary, and two sections of S, and easy bandwidth is available. The wider bandwidth makes negative FBB easier to apply without the amp going unstable. Many guitar amps have negative FB. Somebody has to know all the details of what is being attempted, and at the moment, not enough ppl have the correct details. Maybe we can remedy that a little by putting a bit of knowledge together so that we can have half decent toroids at really low prices. The market is tiny. People have thought of all this before. There are no toroidal OPTs for a 300 watt tube amp available from Hammond. Volume production of 10,000 units is impossible, so such OPTs are specials, and one offs, and will be 3 times the price of some other trannies available of the same size of core. Plitron make really good toroidal OPTs, but one pays for them. It would be hard to compete with them. Perhaps a little on winding technique, little on frequency response, desired magnetic flux, wire specs, impedance matching and whatnot.. it would be good no? I wish you the best of luck with your project. I somehow think that you'd need to be able to better spell out *all* the design details or else you will surely use up the drinking allowance of $50, and it won't be due to coming home under budget. Thanks Pat. Yup the devil's in the planning and detail as always but with a little help from my friends... maybe it's possible to have the drinking budget shared... cb I have rewound a few toroidal transformers by hand. It takes days, at an average of one turn per minute. That was to place more turns onto existing transformers, after taking many turns off, to get the tranny to run with less noise powering a tube amp's rectifier. I reduced the B from the 1.25 T down to 0.85T. Lotsa work because I have no winder, so don't think of DIY, better to have a knowledgeable winder do the lot for you. He just has to know what he's doing, and you have to know too. There are ppl winding trannies using only charts where the turns per volt for 50 Hz mains windings for a given core size and VA is all the info they can deal with. Is your winder intelligent and educated, or just a dummy? Patrick Turner. |
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Hi Phil,
you wrote in one single article to RAT: [...] the Turneroid Parrott [...] the Turneroid Parrott [...] [...] the Turneroid Parrott [...] [...] the Turneroid Parrott [...] [...] the Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] the Turneroid Parrott [...] [...] the Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] the Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turnerpoid parrot [...] [...] the Turneroid Parrott [...] [...] The Turneroid Parrott [...] [...] The Turneroid parrot [...] [...] The Turneroid Parrott [...] ** The Turneroid Parrot is a parrott - he just says the same stupid things over and over and over and over ..... Says who? Tom -- A gleekzorp without a tornpee is like a quap without a fertsneet (sort of). |
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#16
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Hi Yves,
I've seen 5 (and even 6) strings basses, how are they tuned ? Most 5 & 6 strings have the additional strings (compared to the classical 4 string) for extended higher tones playability, just to remove some penalty the bass player has when duelling with an axe man ;-) There is not much what could be gained by having an electric bass string tuned lower than the conventional low E on an electric bass except for a gimmick now an then. Tom -- Falling in love is a lot like dying. You never get to do it enough to become good at it. |
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#17
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Patrick Turner wrote:
in . au, on Sat, 29 May 2004 02:20:41 +1000, : Nope, very litle content theoretically exists lower than the E string on a bass, : : which is at about 80 Hz. I don't play any stringed instruments, but IIRC from general knowledge the lower E string on a bass guitar is tuned to 42Hz, and double that on a guitar. OTOH, just checking my facts moments later, I Googled up this snippet from http://www.prosoundweb.com/recording...onceptions.php "Electric bass - how low does it really go? The main output of a bass E string is primarily around 84Hz, not the 42Hz most bass players imagine. The reason is simple; the string length is too short to produce much fundamental. Yes, it produces some 42Hz, but most of the sound is an octave above that." Interesting ... still, one would want to allow whatever 42Hz was there, no? -- RdM |
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RdM wrote: Patrick Turner wrote: in . au, on Sat, 29 May 2004 02:20:41 +1000, : Nope, very litle content theoretically exists lower than the E string on a bass, : : which is at about 80 Hz. I don't play any stringed instruments, but IIRC from general knowledge the lower E string on a bass guitar is tuned to 42Hz, and double that on a guitar. OTOH, just checking my facts moments later, I Googled up this snippet from http://www.prosoundweb.com/recording...onceptions.php "Electric bass - how low does it really go? The main output of a bass E string is primarily around 84Hz, not the 42Hz most bass players imagine. The reason is simple; the string length is too short to produce much fundamental. Yes, it produces some 42Hz, but most of the sound is an octave above that." Interesting ... still, one would want to allow whatever 42Hz was there, no? -- RdM Good to see somebody corrected me on this, it proves y'all ain't asleep. In Ben Duncan's book, 'Amplifiers' of 1996, he gives the spectral content of a low E string, and its fundemental is 41 Hz. There is a low level sub 3rd harmonic of 14 Hz at -60 dB. There is greater energy in the 2H, and 3H is only -2 dB down, but I guess it depends where the string is plucked as to what harmonics are produced. The plethera of higher harmonics extend to over 1 kHz. These are often boosted in the amp so their levels are way above the fundementals. If a string is plucked right in the centre, there is mostly fundememntal, and the tone is dull and lifeless. Plucked down near the bridge, and the upper harmonics are excited. The spectral analysis graph was reproduced from Stereophile, with permission. Considering how musicians cannot resist gross overload on their amps, having 25 Hz as the Fsat at full power is reasonable; its not even one octave below where you wanna go. 20 Hz would be better. If true pink noise is used to test an OPT, it interesting to see the random saturations of the OPT, and an RC filter to keep out the sub 20 Hz random F peaks is needed. Patrick Turner. |
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"Patrick Turner" In Ben Duncan's book, 'Amplifiers' of 1996, he gives the spectral content of a low E string, and its fundemental is 41 Hz. There is a low level sub 3rd harmonic of 14 Hz at -60 dB. There is greater energy in the 2H, and 3H is only -2 dB down, but I guess it depends where the string is plucked as to what harmonics are produced. The plethera of higher harmonics extend to over 1 kHz. These are often boosted in the amp so their levels are way above the fundementals. If a string is plucked right in the centre, there is mostly fundememntal, and the tone is dull and lifeless. Plucked down near the bridge, and the upper harmonics are excited. The spectral analysis graph was reproduced from Stereophile, with permission. Considering how musicians cannot resist gross overload on their amps, having 25 Hz as the Fsat at full power is reasonable; ** That last remark from the Turneroid Parrot ***contradicts*** everything that can be learnt for reading the previous info. The info very clearly says that the harmonics of the lowest note on a bass have much MORE energy than the fundamental at 42 Hz. This is why a full output power at 40 Hz is not needed - having full power available at 50 Hz is still better than ever needed. The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. ............ Phil |
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#20
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Phil Allison wrote: "Patrick Turner" In Ben Duncan's book, 'Amplifiers' of 1996, he gives the spectral content of a low E string, and its fundemental is 41 Hz. There is a low level sub 3rd harmonic of 14 Hz at -60 dB. There is greater energy in the 2H, and 3H is only -2 dB down, but I guess it depends where the string is plucked as to what harmonics are produced. The plethera of higher harmonics extend to over 1 kHz. These are often boosted in the amp so their levels are way above the fundementals. If a string is plucked right in the centre, there is mostly fundememntal, and the tone is dull and lifeless. Plucked down near the bridge, and the upper harmonics are excited. The spectral analysis graph was reproduced from Stereophile, with permission. Considering how musicians cannot resist gross overload on their amps, having 25 Hz as the Fsat at full power is reasonable; ** That last remark from the Turneroid Parrot ***contradicts*** everything that can be learnt for reading the previous info. The university educated jerk has no clue. If you pluck a string in the centre of its length, the vast majority of energy resides in the fundemental. The Stereophile graph showing spectral content from a bass guitar string is *not gospel*, and shouldn't be taken as the only wave analysis that one would get with every note played. What if the bassist tunes his guitar a bit lower than standard? The info very clearly says that the harmonics of the lowest note on a bass have much MORE energy than the fundamental at 42 Hz. This is why a full output power at 40 Hz is not needed - having full power available at 50 Hz is still better than ever needed. I still believe keeping saturation an octave away is a good thing. The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. ........... Phil And I don't give a **** if Ampeg or Fender have half the turns that I would use on an OPT primary. Their manufacturing techniques seem bean counter derived to me. I prefer to have some real bass capacity extending to 25 Hz, even if it ain't all used. In any case, the amp proposed will develop 700vrms across its primary, and two 240 v standard mains will develop 1.82 Tesla at 700v. Many players would be delighted that the amp might have the added distortion due to the saturation, were it not that the current pulses through the tubes due to saturation might shorten tube life unecessarily. I'd always recommend that 4 x 240v windings be used, and all done as a seriously designed project, and I see no reason to change my ideas. Ppl are welcome to **** around with mains trannies, but for a bass amp I recommend a disciplined design approach only. Its obvious that there are two options, Phil's, which is the lazy man's way to a cheap amp, or mine, slightly more expensive, but with far more bass capacity, and ability to handle higher power at LF if needed. Patrick Turner. |
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"Patrick Turner" Phil Allison wrote: ** That last remark from the Turneroid Parrot ***contradicts*** everything that can be learnt for reading the previous info. The university educated jerk has no clue. ** Parrot ****e - the runny sort. If you pluck a string in the centre of its length, the vast majority of energy resides in the fundamental. ** Bassists do not play like that - plus pickups are placed near one end of the string and so always emphasise harmonics. The Stereophile graph showing spectral content from a bass guitar string is *not gospel*, and shouldn't be taken as the only wave analysis that one would get with every note played. ** Then why the HELL did the Turneroid Parrot produce it as HIS evidence ??????? The mongrel dog has just bitten its owner....... What if the bassist tunes his guitar a bit lower than standard? ** He will be out of tune with the band. The info very clearly says that the harmonics of the lowest note on a bass have much MORE energy than the fundamental at 42 Hz. This is why a full output power at 40 Hz is not needed - having full power available at 50 Hz is still better than ever needed. I still believe keeping saturation an octave away is a good thing. ** Never the issue - the Turneroid Parrott is the one claiming that is MUST be this way or it is **NOT RIGHT ** !! The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. ........... Phil And I don't give a **** if Ampeg or Fender have half the turns that I would use on an OPT primary. ** The Turneroid Parrot cannot even see the point at all. The fact that it standard commercial practise with tube bass heads shows it represents is ver y acceptable performance. I'd always recommend that 4 x 240v windings be used, and all done as a seriously designed project, and I see no reason to change my ideas. ** No one has ever asked the Turneroid Parrott change his view. But would he mind not shoving it down everyone else's throats as HOLY WRIT just because it says so in the damn RDH4 !!!!!! Ppl are welcome to **** around with mains trannies, but for a bass amp I recommend a disciplined design approach only. ** The Turneroid Parrott has no expertise with bass guitar mps - he has no facts, he has no clues. Its obvious that there are two options, Phil's, which is the lazy man's way to a cheap amp, or mine, slightly more expensive, ** It is VASTLY more expensive - since it precludes using the simple, mains style, toroidal tranny option completely. ............. Phil |
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Perhaps he was referring to a standup bass. The strings on a standup bass
are aprox twice the length. Maybe that's why they call it a 'Doublebass' (hehehe). Wait a minute... that should be halfbass shouldn't it? - 5 out of 4 people don't understand fractions. keithw... "Patrick Turner" wrote in message ... In Ben Duncan's book, 'Amplifiers' of 1996, he gives the spectral content of a low E string, and its fundemental is 41 Hz. There is a low level sub 3rd harmonic of 14 Hz at -60 dB. There is greater energy in the 2H, and 3H is only -2 dB down, but I guess it depends where the string is plucked as to what harmonics are produced. Patrick Turner. |
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Phil Allison does get so stupidly excited, doesn't he. The harmonics in bass strings do vary depending where the strings are struck, and it isn't always in the same place. Stereophile's graph is a typical one, but wide variations in harmonic content occurs I built my own 18 string guitar at age 20, and a 12 string. I used to play in a band, and I tuned my guitar low, but by changing the keys I stayed in tune with the rest of the band. I might play in D, but because the guitar was two semi tones lower, it was in tune with ppl playing in C. Or I might play C chords, and ppl were in G, with my 18 stringer at 5 semi tones lower. Played in a band at all Phil? Didn't think so. Phil A can rave all he likes to try to promote his lousy transformer ideas, but he moves me not, and I have my way of doing things, and that's that. I am not a bigot, a parrot, or whatever else, I have my methods; everyone is welcome to try them, or reject them on the grounds of too hard, too expensive, whatever. It worries me not! I simply am never going to advise folks to build lowest grade common denominator equipment. Readers will not learn anything from Phil's post below. Patrick Turner. Phil Allison wrote: "Patrick Turner" Phil Allison wrote: ** That last remark from the Turneroid Parrot ***contradicts*** everything that can be learnt for reading the previous info. The university educated jerk has no clue. ** Parrot ****e - the runny sort. If you pluck a string in the centre of its length, the vast majority of energy resides in the fundamental. ** Bassists do not play like that - plus pickups are placed near one end of the string and so always emphasise harmonics. The Stereophile graph showing spectral content from a bass guitar string is *not gospel*, and shouldn't be taken as the only wave analysis that one would get with every note played. ** Then why the HELL did the Turneroid Parrot produce it as HIS evidence ??????? The mongrel dog has just bitten its owner....... What if the bassist tunes his guitar a bit lower than standard? ** He will be out of tune with the band. The info very clearly says that the harmonics of the lowest note on a bass have much MORE energy than the fundamental at 42 Hz. This is why a full output power at 40 Hz is not needed - having full power available at 50 Hz is still better than ever needed. I still believe keeping saturation an octave away is a good thing. ** Never the issue - the Turneroid Parrott is the one claiming that is MUST be this way or it is **NOT RIGHT ** !! The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. ........... Phil And I don't give a **** if Ampeg or Fender have half the turns that I would use on an OPT primary. ** The Turneroid Parrot cannot even see the point at all. The fact that it standard commercial practise with tube bass heads shows it represents is ver y acceptable performance. I'd always recommend that 4 x 240v windings be used, and all done as a seriously designed project, and I see no reason to change my ideas. ** No one has ever asked the Turneroid Parrott change his view. But would he mind not shoving it down everyone else's throats as HOLY WRIT just because it says so in the damn RDH4 !!!!!! Ppl are welcome to **** around with mains trannies, but for a bass amp I recommend a disciplined design approach only. ** The Turneroid Parrott has no expertise with bass guitar mps - he has no facts, he has no clues. Its obvious that there are two options, Phil's, which is the lazy man's way to a cheap amp, or mine, slightly more expensive, ** It is VASTLY more expensive - since it precludes using the simple, mains style, toroidal tranny option completely. ............ Phil |
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#24
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"Patrick Turner" ** Poly want a cracker ???? Poly is crackers. ............... Phil |
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#25
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"Tom Schlangen" wrote in message
... Hi Yves, I've seen 5 (and even 6) strings basses, how are they tuned ? Most 5 & 6 strings have the additional strings (compared to the classical 4 string) for extended higher tones playability, just to remove some penalty the bass player has when duelling with an axe man ;-) Sorry, not true. A 5-string is almost always tuned B-E-A-D-G (ie a B below the low E on a normal 4-string) while a 6-string adds a high C above the G on a 4-string. There are a few exceptions (eg the Fender Bass VI, which is tuned the same as a guitar ie E-A-D-G-B-E, but an octave lower), but the 5/6 tunings above are the most common instruments. And a few bassists tune their 5-strings E-A-D-G-C giving an extended top range (like the 6) for solos. There is not much what could be gained by having an electric bass string tuned lower than the conventional low E on an electric bass except for a gimmick now and then. Sorry Tom, not true again. The 5-string was developed in the middish-1980s to allow bassists to compete with keyboard players whose then-new/fashionable synthesisers (eg Rolands, Yamaha DX-7s) could go below the low E of a standard bass. They're in common use these days. As well, the low string allows speed/economy of movement by playing "across" the fretboard, rather than having to move one's left hand down the neck to reach the same low note on a 4-string. And 6-strings were developed to allow melodic solos/chords to be played by bassists, which is more difficult (but again, not impossible) on a standard 4-string. I own one of each, plus a fretless 4-string. 8^) Cheers. |
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#26
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"Phil Allison" wrote in message
... The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. There _is_ no "famous and much loved tube bass amp from Fender". Fender have never built a decent tube BASS amp (and I once owned a 1965 Blackface Bassman, which I sold post haste to buy a SS Acoustic, a far superior amp). While the original (now reissued) 40W 4x10" Fender Bassman amp is much lauded, it's as a _guitar_ amp, not for bass duties. As far as Ampeg goes, the tube SVT is almost always paired with one or two 8x10" cabinets which, AFAIK, have relatively little usable output below about 75Hz, and relies on a very prominent second-harmonic of the low notes from the instrument to produce its very distinctive sound. The ear fills in the rest. So the amp's output at 50Hz isn't particularly important anyway, and any distortion due to saturation etc only adds to the combination's overall sound. It's a musical instrument, NOT a hifi amp. |
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#27
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snip...
There is not much what could be gained by having an electric bass string tuned lower than the conventional low E on an electric bass except for a gimmick now and then. Sorry Tom, not true again. The 5-string was developed in the middish-1980s to allow bassists to compete with keyboard players whose then-new/fashionable synthesisers (eg Rolands, Yamaha DX-7s) could go below the low E of a standard bass. They're in common use these days. Ah, here is part of the real justification for having *four* x 240 v primary windings instead of just two on a modified "mains" toroid to get the tranny to go lower than 40 Hz in a bass power amp. snip, Patrick Turner. |
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#28
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"kyser" wrote in message u... So the amp's output at 50Hz isn't particularly important anyway, and any distortion due to saturation etc only adds to the combination's overall sound. It's a musical instrument, NOT a hifi amp. In some ways you're right, in others, I disagree with you a fair bit... Bit by bit... Because the speakers can't put out that much power in the lower range, it doesn't mean that the output transformer shouldn't be able to cope with it. 2 examples: 1) The output transformer saturates with the fundamental. 2) The output transformer doesn't saturate. Which is more desirable? whichever sounds best of course, being simplistic. BUT since we're dealing with a toroidal with relatively unknown saturation characteristics, perhaps it's wise to over-engineer the OT so as to avoid that kind of coloration. Furthermore, if the transformer rolls off from 50-60Hz and the speakers from 80Hz, we'll be ending up with a steeper rolloff where it's generally accepted that a gentle bass rolloff is more desirable. OTOH, even in guitar amps, I prefer the sound before the OT saturates... WRT famous Fender bass amps: http://www.timeelect.com/400-PS-IDX.htm Famous - not popular OK? WRT Ampeg, their 8x10" enclosures have a stated F3 of 50Hz which means that there is still usable output well down to 40Hz. It's often a misconception that the drivers magically cut off below the F3 but combine this with your room resonance curve and you'll probably need to back bass off below 100Hz rather than boost it for a flat response. Similarily, the amp has a *gain* frequency response (-3dB) of 40-15kHz - sure it might not be able to roduce that in terms of full power response but hitting the edges that hard isn't what I'm after (I've got guitar amps for that)... Still, I'm not here to be anal and dig deeply into some loose comments - just clearing up a couple of things I can't see where you got the logic for them from... cb |
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#29
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kyser wrote: "Phil Allison" wrote in message ... The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. There _is_ no "famous and much loved tube bass amp from Fender". Fender have never built a decent tube BASS amp (and I once owned a 1965 Blackface Bassman, which I sold post haste to buy a SS Acoustic, a far superior amp). While the original (now reissued) 40W 4x10" Fender Bassman amp is much lauded, it's as a _guitar_ amp, not for bass duties. As far as Ampeg goes, the tube SVT is almost always paired with one or two 8x10" cabinets which, AFAIK, have relatively little usable output below about 75Hz, and relies on a very prominent second-harmonic of the low notes from the instrument to produce its very distinctive sound. The ear fills in the rest. So the amp's output at 50Hz isn't particularly important anyway, and any distortion due to saturation etc only adds to the combination's overall sound. It's a musical instrument, NOT a hifi amp. Phil Allison maintains a bass amp transformer could saturate at 50 Hz, and still be fine for a bass amp. I say 25 Hz is better, because you never know how low one might wanna go, and the distortion which is due to saturation comes with extremely high short circuit current pulses through the tranny and tubes, since the magnetic field collapses during parts of the wave cycles, and the tube sees its self connected to the DC resistance of the transformer windings. Its all the more worse with toroidal cores, which have high U material, because the iron is a spiral strip with the direction of the crystals all lined up in the same direction. E&I transformers have the crytal structure at 90 degrees where the Is are against the Es, and so its like having a tiny air gap. In fact, there is probably no need to use an expensive grain oriented Si Fe E&I core if the core is simply a big enough lump of plain non oriented Si Fe material. And the lams need not be stacked up EI, IE, EI, IE, they can be stacked up in groups of 4I against 4E, and so on. This will make the core less prone to rapid saturation. Some of my hi-fi amps can be run at full power and saturation does not occur until you get to 8 Hz, using cores with E&I lams, and these would make excellent trannies for a bass amp, so the distortion is from harmless voltage clipping, not the severe current pulses in the OPT during saturation events, which could lead to early tube failure. I maintain my position that to build 300 watt bass amp OPTs without enough turns and iron to allow full power at 25 Hz is sheer folly. And aiming for Fsat at 10 Hz is so much the better! Patrick Turner. |
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#30
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"Patrick Turner" wrote in message ... RdM wrote: Patrick Turner wrote: in . au, on Sat, 29 May 2004 02:20:41 +1000, : Nope, very litle content theoretically exists lower than the E string on a bass, : : which is at about 80 Hz. I don't play any stringed instruments, but IIRC from general knowledge the lower E string on a bass guitar is tuned to 42Hz, and double that on a guitar. OTOH, just checking my facts moments later, I Googled up this snippet from http://www.prosoundweb.com/recording...onceptions.php "Electric bass - how low does it really go? The main output of a bass E string is primarily around 84Hz, not the 42Hz most bass players imagine. The reason is simple; the string length is too short to produce much fundamental. Yes, it produces some 42Hz, but most of the sound is an octave above that." Interesting ... still, one would want to allow whatever 42Hz was there, no? -- RdM Good to see somebody corrected me on this, it proves y'all ain't asleep. In Ben Duncan's book, 'Amplifiers' of 1996, he gives the spectral content of a low E string, and its fundemental is 41 Hz. There is a low level sub 3rd harmonic of 14 Hz at -60 dB. There is greater energy in the 2H, and 3H is only -2 dB down, but I guess it depends where the string is plucked as to what harmonics are produced. The plethera of higher harmonics extend to over 1 kHz. These are often boosted in the amp so their levels are way above the fundementals. If a string is plucked right in the centre, there is mostly fundememntal, and the tone is dull and lifeless. Plucked down near the bridge, and the upper harmonics are excited. There are 2 ways of thinking about this (as usual). Considering the speakers, a LOT of bass speakers can't handle more than 60-80W before they're well outside their operating range below 60Hz... Thus, it would be "desirable" to have the OT protect them in a ways... OTOH, strong bottom end will cause funnies to happen to the higher overtones at the same time - which may or may not be desirable depending on if you like the sound produced more than anything. In my experience and to my ears however, I don't find that sort of thing desirable and would in fact much prefer my 15"s to have that extra low end available - even if I back off the bass a little on the preamp. I think we're comparing apples and pears here though... the output of a bass guitar often hass very little to do with the output of the speakersand determining which one is critical for this argument is non-trivial and difficult at the same time. To saturate or not to saturate, to back off the bass in the preamp or let the saturation take care of it... I kind of prefer the capable amp side of things though knowing that it's harder to put something back that's been sucked out than to EQ it away a little... cb |
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#31
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"Patrick Turner" wrote in message ... Phil Allison maintains a bass amp transformer could saturate at 50 Hz, and still be fine for a bass amp. Patrick, it's very true that it *may* be fine for a bass amp so long as that kind of saturation is good to your ears. OTOH, I've not found it good to mine. I say 25 Hz is better, because you never know how low one might wanna go, and the distortion which is due to saturation comes with extremely high short circuit current pulses through the tranny and tubes, since the magnetic field collapses during parts of the wave cycles, and the tube sees its self connected to the DC resistance of the transformer windings. Its all the more worse with toroidal cores, which have high U material, because the iron is a spiral strip with the direction of the crystals all lined up in the same direction. Phil doesn't seem to be taking that into account but wrt to the core, Phil has suggested 50% oversize - mailny due to winding practicalities and 20% extra copper on the primary. Still, it's up to me to make the decisions and it's my wallet after all. I don't want saturation and I do want plenty of safety in terms of copper too so the limiting factors are likely to be what I can get for the money right? The limit of what's reasonable is a 800VA core with two primaries as big as I can get them and the secondaries wound onto them. E&I transformers have the crytal structure at 90 degrees where the Is are against the Es, and so its like having a tiny air gap. In fact, there is probably no need to use an expensive grain oriented Si Fe E&I core if the core is simply a big enough lump of plain non oriented Si Fe material. And the lams need not be stacked up EI, IE, EI, IE, they can be stacked up in groups of 4I against 4E, and so on. This will make the core less prone to rapid saturation. I can always replace the transformer with an EI core later but am curious as to how this one will sound with a toroidal OT. Some of my hi-fi amps can be run at full power and saturation does not occur until you get to 8 Hz, using cores with E&I lams, and these would make excellent trannies for a bass amp, so the distortion is from harmless voltage clipping, not the severe current pulses in the OPT during saturation events, which could lead to early tube failure. Another good reason to oversize then... I maintain my position that to build 300 watt bass amp OPTs without enough turns and iron to allow full power at 25 Hz is sheer folly. And aiming for Fsat at 10 Hz is so much the better! I'm still 100% inclined to go with you there... I've been knocking your equation around a bit and the other data too and it seems that it's really a matter of a LOT of turns on the primary to give a decent number of turns for the secondaries on the transformers we're talking about. Balancing the copper losses is going to be a nightmare though I suspect. I can see where you get the 639V (550V/1.4k/289W) from but a factor you might be missing is the "abuse criteria" that causes musicians to run their gear at and beyond their conventional limits. I've messed around with a scope to see how bad clipping gets while sounding good and it's well beyond waveforms you'd call clean with as much as 20% thd sounding growly but still "clean". I couldn't freeze the old scope on the transients however to be able to tell whether the transients peaked much in the voltage range or "limited" at those peak anode to anode voltages. In my example for 300W output into 1.5kohms, peaks of 950V anode to anode would be present causing me no little concern for the winding/insulation. As an example, your 100W Marshall user typically puts out 140W of power - whether that's coltage peaks or just the square waves contributing to the power output isn't something I can tell too easily but the 1.4:1 ratio makes me think that it's almost DC at the peak voltages... Still, I get a chance to go over the whole thing with the "expert" tomorrow and find out how much he knows to be able to do a good job of it. Now for a bit of my madness... The latest idea I've been knocking around is to have 4 pairs of output valves and 2 separate mains transformers for the output stage (meaning more thinner windings and more insulation but it's an idea anyhow...) and separate secondaries for each quad so that it's possible to switch half the valves off and raise the impedance for lower power "practice" and at the same time make it easier to bias/balance the valves in the output stage. Taking this idea further, separate pairs wouldn't be bad allowing ranges from 100 to 400W and individiual pairs to be used or even a/b'd. Think it's worth pursuing? Anyway Patrick, thanks very much for your patience and advice once more, hopefully they can wind you a few too! Regards, Chris |
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#32
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"Chris Berry" wrote in message
... WRT famous Fender bass amps: http://www.timeelect.com/400-PS-IDX.htm Famous - not popular OK? I don't think they're even "famous", and doubt that the majority of Fender devotees would know of their existence, despite Mr Koerner's (an avid fan of these monstrosities) one-man fanatical devotion on his unfinished web page (and occasional contributions to the Fender Discussion Page http://www.fenderforum.com/forum.html) Who in their right mind would lug around an exceedingly heavy amp head with THREE separate tube output stages of ~130W (and attendant OPTs) with a voracious appetite for GE 6550s which required THREE separate 1x18" folded horn cabinets the size of a home refrigerator to get full output. A dinosaur ... I can't recall a _single_ professional bass player who used the things (Koerner's page on this subject is "under construction", with only a single pic of himself (who???) playing a Gibson Ripper/Grabber, another dog from that era which quickly sank from view, but _still_ has a few earnest devotees, God knows why). Sales were poor, and Fender (rightly, if you're not Koerner) dropped the PS400 after a few years. The manufacturing costs must have been horrendous, and it's amazing (and possibly a credit to Ed Jahns' persistence) that they even built the thing in the first place! The bass amp "de rigeur" of the era was the SS Acoustic 360/370, due in part to it's use by Jaco Pastorius, John Paul Jones of Led Zepplin and others. AFAIK, partially due to business problems, the Ampeg SVT was also in decline at the time. It's interesting to note that many, if not the the majority of bass players today use SS amps (eg SWR, now owned by Fender but a direct descendent of Acoustic, Trace Elliott, Ashdown, Gallien-Kreuger, Peavey etc etc) which are small, light and powerful, in combination with 4x10" cabs, and in some instances with a 12AX7 in the pre-amp which can be mixed in for some "tube sound". The Ampeg SVT/8x10" cab still has its following, especially in the alternative/"grunge" scene because of its power and distinctive (distorted) sound, but unlike guitarists, bassists aren't obsessed with "tube sound" and happily use SS amps as above. WRT Ampeg, their 8x10" enclosures have a stated F3 of 50Hz which means that there is still usable output well down to 40Hz. It's often a misconception that the drivers magically cut off below the F3 I didn't suggest that, but output _does_ fall off substantially .... but combine this with your room resonance curve and you'll probably need to back bass off below 100Hz rather than boost it for a flat response. Come on! Very few bassists seek a "flat response" anyway. Reggae players want as much boom and thump as possible (lotsa bass boost and 15"/18" speakers); the alt/grunge/heavy metal players love their SVTs as above; and more "modern players into slapping favour high power/"hifi" SS amps (Trace, Ashdown, SWR etc, or pre-power amps of even a Kw or so, some with bi-amping and sub-harmonic generators) with fast-responding 4x10" cabs and _lots_ of control over the mid-range with both shaping switches and graphic equalisers tailored for bass instruments. Mark King of Level 42 did a lot to develop this style, and his current Ashdown rig's specs are here http://www.ashdownmusic.co.uk/bass/detail.asp?ID=53 Similarily, the amp has a *gain* frequency response (-3dB) of 40-15kHz - sure it might not be able to produce that in terms of full power response but hitting the edges that hard isn't what I'm after (I've got guitar amps for that)... Still, I'm not here to be anal and dig deeply into some loose comments - just clearing up a couple of things I can't see where you got the logic for them from ... Perhaps the above will help? 8^) |
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#33
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"kyser" ... "Phil Allison" The fact that famous and much loved tube bass amps from Ampeg and Fender cannot produce their full rated power at or below 40 Hz is ALL you need to know to justify a design where core saturation first begins at 50 Hz. There _is_ no "famous and much loved tube bass amp from Fender". ** There are in fact quite a few, the Bassmans ( 50, 100 and 135 watt) for a start and other less common ones like the PS400 - 450 watt head that used 6 x 6550s. All these amps are famous and very much sought after by bass players. Fender have never built a decent tube BASS amp (and I once owned a 1965 Blackface Bassman, which I sold post haste to buy a SS Acoustic, a far superior amp). ** That is merely your asinine opinion. (snip) So the amp's output at 50Hz isn't particularly important anyway, and any distortion due to saturation etc only adds to the combination's overall sound. ** Correct - now go tell that to the Turneroid Parrot. ............ Phil |
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#34
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"Patrick Turner" I maintain my position that to build 300 watt bass amp OPTs without enough turns and iron to allow full power at 25 Hz is sheer folly. ** The Turneroid Parrot's "position" is a house of cards perched on a castle made of sand. And aiming for Fsat at 10 Hz is so much the better! ** Pure ****wittery. ............... Phil |
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#35
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"Phil Allison" wrote in message
... ** There are in fact quite a few, the Bassmans ( 50, 100 and 135 watt) for a start and other less common ones like the PS400 - 450 watt head that used 6 x 6550s. All these amps are famous and very much sought after by bass players. Er, pardon me, Phil, but I've actually _owned_ and used a genuine '65 Blackface Bassman 50 (amp and 2x12" cab), and a '70s Silverface Bassman 70 head. Have you? They are/were fairly dreadful BASS amps (low power, farty sound) although not bad as guitar amps (while lacking vibrato and reverb) and this is reflected in their comparatively low resale prices when compared with other contemporary Fender guitar amps (eg Deluxe Reverbs, Pro Reverbs, Vibroluxes, Concerts etc) of the period. I've dealt with the PS400 in another post here, and as I said there, I can't think of a _single_ pro player who used one for any length of tiime. Acoustic 360/370s were de rigeur (eg Jaco) at the time. Fender also made a more recent line of SS "Bassman" amps which never achieved great success with professionals (I own a Dual Bass 400 head from this period - 2x200W RMS and biampable - not a bad amp at all, but it sold poorly and was dropped). They've _never_ been noted as a great manufacturer of BASS amps (as opposed to "bass" amps used with 6 string guitars eg the 4x10" 59 Bassman LTD Reissue http://www.fender.com/products/show.php?partno=2171000, listed on their website as a guitar amp). This deficiency is, in part, why they recently bought SWR (as I noted elswhere, a direct descendant of Acoustic through its founder, Steve Rabe), and Sunn to compete with Ampeg in the 200+ watt tube bass amp category. Fender have never built a decent tube BASS amp (and I once owned a 1965 Blackface Bassman, which I sold post haste to buy a SS Acoustic, a far superior amp). ** That is merely your asinine opinion. But based on personal usage and fact, not supposition and hearsay, as in YOUR case. Now **** off and try to insult someone else with your tired, second-hand opinions, there's a dear! |
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#36
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"kyser" "Phil Allison" ** There are in fact quite a few, the Bassmans ( 50, 100 and 135 watt) for a start and other less common ones like the PS400 - 450 watt head that used 6 x 6550s. All these amps are famous and very much sought after by bass players. Er, pardon me, Phil, ** I do not pardon jerks. but I've actually _owned_ and used a genuine '65 Blackface Bassman 50 (amp and 2x12" cab), and a '70s Silverface Bassman 70 head. Have you? ** Irrelevant to whether they are famous and greatly liked by many others. I've dealt with the PS400 in another post here, and as I said there, I can't think of a _single_ pro player who used one for any length of tiime. * Irrelevant to whether they are famous and greatly liked by many others. Acoustic 360/370s were de rigeur (eg Jaco) at the time. ** Worst piles of SS junk ever made - I remember with dread having to service the POS. Fender have never built a decent tube BASS amp (and I once owned a 1965 Blackface Bassman, which I sold post haste to buy a SS Acoustic, a far superior amp). ** That is merely your asinine opinion. But based on personal usage and fact, not supposition and hearsay, as in YOUR case. ** An even more asinine opinion than the previous ones. ............... Phil |
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#37
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"kyser" Who in their right mind would lug around an exceedingly heavy amp head with THREE separate tube output stages of ~130W (and attendant OPTs) with a voracious appetite for GE 6550s .... ** You are wrong as well as stupid - the PS 400 has one output stage with one output transformer. see: http://www1.korksoft.com/~schem/fenderamps/400ps.pdf which required THREE separate 1x18" folded horn cabinets the size of a home refrigerator to get full output. A dinosaur ... ** Players could use any speaker system they pleased, eg 3 quad boxes or 6 x 15 inch JBL K140s each it its own tuned box as my customer ( Ian Rilen of Rose Tattoo) did. He used the number of boxes need for a given gig as the PS400 allows the 6550 tubes to be operated in pairs. As far as the weight is concerned - ever heard of roadies ?? .............. Phil |
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"Phil Allison" wrote in message
... ** I do not pardon jerks. You must suffer an inordinate amount of self-loathing, then, Phil! LOL!!!! but I've actually _owned_ and used a genuine '65 Blackface Bassman 50 (amp and 2x12" cab), and a '70s Silverface Bassman 70 head. Have you? ** Irrelevant to whether they are famous and greatly liked by many others. They aren't! Trust me ..... I've dealt with the PS400 in another post here, and as I said there, I can't think of a _single_ pro player who used one for any length of tiime. * Irrelevant to whether they are famous and greatly liked by many others. Again, they aren't. Once again Koerner can't muster a SINGLE pro user on his website. Acoustic 360/370s were de rigeur (eg Jaco) at the time. ** Worst piles of SS junk ever made - I remember with dread having to service the POS. Jesus, how would you deal with a current modelling amp (eg a Line 6, Fender Cyber Twin etc), then? AFAIK, Acoustics _still_ have a reputation for power, great sound, simple circuitry, readily available components, and high reliability under heavy touring conditions. A lot are still in use today. Sure you're not thinking about something else? Or were they beyond your abilities, even _with_ simple circuitry? There'd be a far greater number of bass players from the '70s who remember Acoustics with affection, than PS400s which almost sold in single digits. |
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#39
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"kyser" "Phil Allison" ** I do not pardon jerks. You must suffer an inordinate amount of self-loathing, then, Phil! LOL!!!! ** You are the posturing jerk here - not me. but I've actually _owned_ and used a genuine '65 Blackface Bassman 50 (amp and 2x12" cab), and a '70s Silverface Bassman 70 head. Have you? ** Irrelevant to whether they are famous and greatly liked by many others. They aren't! Trust me ..... ** They are, and you are a liar. I've dealt with the PS400 in another post here, and as I said there, I can't think of a _single_ pro player who used one for any length of tiime. ** Irrelevant to whether they are famous and greatly liked by many others. Again, they aren't. ** They are. Once again Koerner can't muster a SINGLE pro user on his website. ** Irrelevant to whether they are famous and greatly liked by many others. Acoustic 360/370s were de rigeur (eg Jaco) at the time. ** Worst piles of SS junk ever made - I remember with dread having to service the POS. Jesus, ** No need to address me so formally. AFAIK, ** But you have already proved you do not *know* anything. .............. Phil |
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#40
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"Phil Allison" wrote in message
... "kyser" Who in their right mind would lug around an exceedingly heavy amp head with THREE separate tube output stages of ~130W (and attendant OPTs) with a voracious appetite for GE 6550s .... ** You are wrong as well as stupid - the PS 400 has one output stage with one output transformer. see: http://www1.korksoft.com/~schem/fenderamps/400ps.pdf Point taken, it's a while since I've seen the schematic, but it still had 3 separate secondary windings on the OPT (huh?) which required THREE separate 1x18" folded horn cabinets the size of a home refrigerator to get full output. Madness ...... ** Players could use any speaker system they pleased, eg 3 quad boxes or 6 x 15 inch JBL K140s each it its own tuned box as my customer ( Ian Rilen of Rose Tattoo) did. He used the number of boxes need for a given gig as the PS400 allows the 6550 tubes to be operated in pairs. But the 1x18" folded horn was the recommended Fender cab (see Koerner's site) although I agree, not mandatory ..... And great, Phil, you've at least named _one_ semi-famous user, whom the Yanks won't recognise, anyway. But why bother with all the heat, weight and complication in the first place. If the things were so wonderful, why didn't any famous players use them. Jaco Pastorious of Weather Report (and his Jazz Bass/Acoustic 360 sound) is _still_ revered decades later. While I remember Ian Rilen, how many others do? As far as the weight is concerned - ever heard of roadies ?? LOL! |
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