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#41
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"Phil Allison" wrote in message ... ** Worst piles of SS junk ever made - I remember with dread having to service the POS. Jesus, ** No need to address me so formally. Oh I'm not. I have several rather more apt salutations for you, but they're not really appropriate on an open forum! LOL And you've failed to address your ability to service a modern modelling guitar amp, if you had trouble coping with a straight-forward early '70s transistor bass amp design. |
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#42
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"kyser" "Phil Allison" 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 .... ** How completely awful - THREE seperate windings - many as that - shock, horror !!!! ** 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.... ** Irrelevant to the amp itself completely. And great, Phil, you've at least named _one_ semi-famous user, whom the Yanks won't recognise, anyway. ** Irrelevant to the amp itself completely. But why bother with all the heat, weight and complication in the first place. ** Irrelevant to the amp itself completely If the things were so wonderful, ** They are a famous amp and very much liked for their sound by the players who used them - QED. why didn't any famous players use them. ** You have not proved that claim. .............. Phil |
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#43
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"kyser" "Phil Allison" ** Worst piles of SS junk ever made - I remember with dread having to service the POS. Jesus, ** No need to address me so formally. Oh I'm not. ** You just did - ******. And you've failed to address your ability ...... ** Are you one drugs, Kyser ? If not - then start now - you need them. ................ Phil |
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#44
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"Phil Allison" wrote in message
... Point taken, it's a while since I've seen the schematic, but it still had 3 separate secondary windings on the OPT .... ** How completely awful - THREE seperate windings - many as that - shock, horror !!!! But why bother? What does it contribute to the sound? And why have to lug 3 cabs (even with roadies) to get full output? Idiosyncratic? Yes. Necessary? No. A commercial and artistic flop? Certainly! ** They are a famous amp Only amongst a few devotees and collectors .... and very much liked for their sound by the players who used them - QED. Okay, now we've got the famous(?) Rich Koerner, and the (slightly) famous Ian Rilen and er, .... then there's er, .... and not forgetting er .... |
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#45
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"Phil Allison" wrote in message
... Jesus, ** No need to address me so formally. Oh I'm not. ** You just did - ******. It was an exclamation of despair at your arrogance, rudeness and general lack of couth (and AFAIK, ability), Phil! And thanks for all the selective snips, as you usually do with posters who choose to engage in your peurile debates so you can appear to "win". And you've failed to address your ability ...... ** Are you one drugs, Kyser ? If not - then start now - you need them. "One drugs"? Have you forgotten your own medication today, Phil? So, CAN you service a Line 6 modelling amp, or are you really just an old tube jockey who manages by unplugging and replacing them until something works? |
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#46
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"Chris Berry" wrote in message
... BTW, are you the Chris Berry looking for a valuation on an Acoustic 140 head here? http://www.guitar-forum.net/bass/Wha..._33143 3.html |
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#47
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"kyser" wrote in message u... "Chris Berry" wrote in message ... BTW, are you the Chris Berry looking for a valuation on an Acoustic 140 head here? http://www.guitar-forum.net/bass/Wha..._33143 3.html Yup but that oportunity has passed me by... cb |
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#48
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"kyser" wrote in message
u... "One drugs"? Have you forgotten your own medication today, Phil? Now now Kyser, the sign says don't feed the trolls.  Tim -- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games: http://webpages.charter.net/dawill/tmoranwms |
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#49
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"kyser" wrote in message u... "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) They're famous for all the right and wrong reasons. The PS300 was for the more reasonable side of things... 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 ... More reasons that it's famous... 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). You wanted famous man... 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. Well valve bass amps have never been that popular due to the weight and size of the rigs overall. Unfortunately though there's nothing much on the market that allows you to get an SVT sound without the van, roadies or backache.. 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". That's because bassists haven't been clued up to the fact that it's overdriven output tubes that cause *the sound* and think a ube will warm things up for them. The other main reason is weight. 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. A bit of a fallacy I think. They love their SVT's and such but think of the change in sound similarily to how they'd consider a fuzz box. SS popularity is such that you can have a 2400W power amp for the same weight as a 300W SVT. If you're carrying your own gear..... 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. It's what they get in a lot of the venues they play in. factor in room acoustics ... Sure they might not aim for it they just compensate for it making things "not too boomy" . Hence a big distinction needs to be made between gig size and amp size... The right tools for the right job... 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. Mostly useless stuff... all those knobs eh? the biamping tends to be very passe at the moment too. Your "stock" giggers rig is a good preamp, a good ss power amp, a 2 or 4x10 plus a 15". Unless you're talking Eden where a 2x10" should be enough. 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 There's often a huge difference between what artists endorse and what they play. cb |
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#50
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"Chris Berry" wrote in message
... "kyser" wrote in message u... "Chris Berry" wrote in message ... BTW, are you the Chris Berry looking for a valuation on an Acoustic 140 head here? http://www.guitar-forum.net/bass/Wha..._33143 3.html Yup but that oportunity has passed me by... cb Just curious - I owned a 140 for quite a long time, and often regret selling it. Simple, light, reliable and great sound. All the things a Blackface Bassman (to which it bore a certain resemblance) should have been! 8^) |
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#51
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"Chris Berry" wrote in message
... Without wishing to prolong the discussion too much .... They're famous for all the right and wrong reasons. The PS300 was for the more reasonable side of things ... Agreed, but I don't think they sold too many of them, either. I've never seen one, and only know of them from the Fender Field Guide (http://www.ampwares.com/ffg/). Who in their right mind would lug around an exceedingly heavy amp head with THREE separate tube output stages of ~130W (and attendant OPTs) I stand corrected on this. One OPT with three secondaries (and needing 3 enclosures) to get full power. Nutty enough, IMO! More reasons that it's famous... Or infamous? 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 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). You wanted famous man... God certainly is, but I'm unconvinced about PS400s, Koerner or Rippers and Grabbers. LOL Well valve bass amps have never been that popular due to the weight and size of the rigs overall. Unfortunately though there's nothing much on the market that allows you to get an SVT sound without the van, roadies or backache.. 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. A bit of a fallacy I think. They love their SVT's and such Correction. Some love their SVTs and such ... but think of the change in sound similarily to how they'd consider a fuzz box. SS popularity is such that you can have a 2400W power amp for the same weight as a 300W SVT. If you're carrying your own gear..... (On "sophisticated" SS amps) Mostly useless stuff... all those knobs eh? the biamping tends to be very passe at the moment too. Agreed. But the mid-scoop switches, graphics and sub-harmonic synthesisers (SWR Interstellar Overdrive, many Ashdown amps, some others) seem pretty popular as well. Your "stock" giggers rig is a good preamp, a good ss power amp, a 2 or 4x10 plus a 15". Unless you're talking Eden where a 2x10" should be enough. So lets hear it for Hartke, Peavey, and Gallien-Kreuger, eh? LOL. Mark King of Level 42 did a lot to develop this (slapping) style, and his current Ashdown rig's specs are here http://www.ashdownmusic.co.uk/bass/detail.asp?ID=53 There's often a huge difference between what artists endorse and what they play. Broadly speaking, I agree with you, but King has been a long term supporter of first Trace Elliot (he did a lot to establish the brand in the public eye), and now Ashdown (whose MD was one of the founders of Trace, and left to form Ashdown after the company was bought and "deconstructed" by Gibson). Still can't think of any endorsees for the PS400 (apart from Koerner) though. 8^) |
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#52
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"kyser" wrote in message ... Who in their right mind would lug around an exceedingly heavy amp head with THREE separate tube output stages of ~130W (and attendant OPTs) I stand corrected on this. One OPT with three secondaries (and needing 3 enclosures) to get full power. Nutty enough, IMO! Considering the speakers available at the time, 145W was enough for any cab. +6dB-9dB/cab also sounds good to me. Further to that it also means that you're likely to be running at a lower impedance - less power OK but better than a higher impedance frying your OT. More reasons that it's famous... Or infamous? 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 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). You wanted famous man... God certainly is, but I'm unconvinced about PS400s, Koerner or Rippers and Grabbers. LOL Well valve bass amps have never been that popular due to the weight and size of the rigs overall. Unfortunately though there's nothing much on the market that allows you to get an SVT sound without the van, roadies or backache.. 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. A bit of a fallacy I think. They love their SVT's and such Correction. Some love their SVTs and such ... And others can't afford them... but think of the change in sound similarily to how they'd consider a fuzz box. SS popularity is such that you can have a 2400W power amp for the same weight as a 300W SVT. If you're carrying your own gear..... (On "sophisticated" SS amps) Mostly useless stuff... all those knobs eh? the biamping tends to be very passe at the moment too. Agreed. But the mid-scoop switches, graphics and sub-harmonic synthesisers (SWR Interstellar Overdrive, many Ashdown amps, some others) seem pretty popular as well. at the end of the day, gimicks do sell amps but that's not what makes the amp a keeper. Your "stock" giggers rig is a good preamp, a good ss power amp, a 2 or 4x10 plus a 15". Unless you're talking Eden where a 2x10" should be enough. So lets hear it for Hartke, Peavey, and Gallien-Kreuger, eh? LOL. Hartke got a good deal of rep from Jaco. GK don't have a bad name at all. Peavey though.... Mark King of Level 42 did a lot to develop this (slapping) style, and his current Ashdown rig's specs are here http://www.ashdownmusic.co.uk/bass/detail.asp?ID=53 There's often a huge difference between what artists endorse and what they play. Broadly speaking, I agree with you, but King has been a long term supporter of first Trace Elliot (he did a lot to establish the brand in the public eye), and now Ashdown (whose MD was one of the founders of Trace, and left to form Ashdown after the company was bought and "deconstructed" by Gibson). Makes you think how much of that is friendship - or share ownership... Still can't think of any endorsees for the PS400 (apart from Koerner) though. 8^) They're too rare and too excessive. cb |
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#53
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"Chris Berry" wrote in message
... Broadly speaking, I agree with you, but King has been a long term supporter of first Trace Elliot (he did a lot to establish the brand in the public eye), and now Ashdown (whose MD was one of the founders of Trace, and left to form Ashdown after the company was bought and "deconstructed" by Gibson). Makes you think how much of that is friendship - or share ownership... A bit cynical, there! From what I can recall (and bearing in mind that I've never particularly liked Level 42, or King's playing) Trace was a small, specialist manufacturer working out of a musical instrument shop in Essex, UK in the late 1970s who developed more powerful (and versatile) bass amps for the emerging "slap" style of the time. King was an early user (but not an endorsee, see http://www.globalbass.com/archives/n.../Mark_King.htm where he claims he has never endorsed any product) who was regularly seen with the amps and AFAIK had a fair bit of input into their development (really no different to Fender's early relationships with various artists who worked with them - despite popular myth, Leo didn't do it all alone!). King appears to have had a similar relationship with Status basses, which he used for a while after Alembics. And while he claims the Ashdown people as "old friends", and _did_ use the amp I mentioned for a recent tour (they had pics of the stage rig on their site a few months ago), another interview suggests he's now considering an Eden rig. |
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#54
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"kyser" wrote in message u... "Chris Berry" wrote in message ... Broadly speaking, I agree with you, but King has been a long term supporter of first Trace Elliot (he did a lot to establish the brand in the public eye), and now Ashdown (whose MD was one of the founders of Trace, and left to form Ashdown after the company was bought and "deconstructed" by Gibson). Makes you think how much of that is friendship - or share ownership... A bit cynical, there! No. It's a business - not a charity. From what I can recall (and bearing in mind that I've never particularly liked Level 42, or King's playing) Trace was a small, specialist manufacturer working out of a musical instrument shop in Essex, UK in the late 1970s who developed more powerful (and versatile) bass amps for the emerging "slap" style of the time. There are 3 kinds of endorsement. Buy for less but show the stuff at every gig, being given/loaned the stuff for every gig and have a model named/designed for you where you get royalties. I guess buy for less and be free to use it at your gigs because you actually like it is where "not an endorsement" comes in. King was an early user (but not an endorsee, see http://www.globalbass.com/archives/n.../Mark_King.htm where he claims he has never endorsed any product) who was regularly seen with the amps and AFAIK had a fair bit of input into their development (really no different to Fender's early relationships with various artists who worked with them - despite popular myth, Leo didn't do it all alone!). King appears to have had a similar relationship with Status basses, which he used for a while after Alembics. And while he claims the Ashdown people as "old friends", and _did_ use the amp I mentioned for a recent tour (they had pics of the stage rig on their site a few months ago), another interview suggests he's now considering an Eden rig. Like I said, It's a business. Wouldn't happen if there wasn't a financial interest behind it. Call me a cynic if you like but gear for consulting, input and a bit of advertising is a commercial transaction. cb |
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#55
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"kyser" wrote in message u... : "Phil Allison" wrote in message : ... snip : While the original (now reissued) 40W 4x10" Fender Bassman amp is much : lauded, it's as a _guitar_ amp, not for bass duties. Funny you should mention it. I thought this amp was for Harmonica players! Cheers Wild Phil Harmonica |
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#56
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"anybody-but-bush" Anybody But wrote in message
ink.net... "kyser" wrote in message u... : While the original (now reissued) 40W 4x10" Fender Bassman amp is much lauded, it's as a _guitar_ amp, not for bass duties. Funny you should mention it. I thought this amp was for Harmonica players! LOL!!! |
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#57
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We all got a laugh when Phil Allison tried to reply on the subject of a toroidal OPT suitable for 300 watts. Ppl interested should take a look at the Plitron toroidal data for the 300 watt model at http://www.plitron.com/PDF/PB/specs/pat4140-00.pdf If one works from the data given about the DCR, and the size of the core, its becomes obvious that they would have around 3,200 turns on the primary of 0.65 mm dia wire. This allows for 692 vrms applied to a get a B of 1.8 Tesla at 14 Hz. At 50 Hz, the B = 0.5 Tesla, less than half what one would run a mains transformer at. So its obvious that Plitron believe in using a combination of iron and turns resulting in a low B and hence low Fsat. Is the small brained Phil Allison going to suggest that Plitron have no clue? The PLitron transformer is only 6.5 Kgs in weight, and yet delivers just under 10% total winding losses. The bandwidth is 14 to 88 kHz. I used a lot more iron with E&I, but with many less turns, and more interleaving to get 270 kHz BW, and lower winding losses, but the same LF performance. But rather than anyone order a mains derived transformer they could do a lot worse than try Plitron. I estimated the core material is a GOSS toroid 135 mm oa dia, with strip width of 75 mm, and build up of about 40 mm. This means the hole is 55 mm dia, but I may be incorrect. The P inductance is quoted at over 1,200 Henrys, so the turns I guessed would be somewhere near what I said. If you were to use a core this size for 240v mains at 1.2T, the turns required would be 300 turns, so its 1.25 turns per volt, which sounds just right for this size of core section. Now I suggested that 4 x 240 volt mains primaries would have to be used to make a primary suitable for use for a 300 watt tube bass amp. On a core of the size Plitron use, 1,200 turns would give a B = 1.8T at 24 Hz at 692 vrms anode to anode. But Plitron seem to use over 10 times the turns needed for 240 volts. Don't ask me what the cost of a Plitron is. Patrick Turner. |
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#58
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"Patrick Turner" We all got a laugh when Phil Allison tried to reply on the subject of a toroidal OPT suitable for 300 watts. ** TheTurneroid Parrot is delivering us more of his smelly droppings. Is the small brained Phil Allison going to suggest that Plitron have no clue? ** The Turneroid Parrott cannot tell what is actually needed for a bass guitar amp from what is pure wank value for hi-fi masturbators like him. ................ Phil |
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#59
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Below, Phil Allison shows again he has no idea about output transformers,
choosing to insult rather than to address the many technical issues raised in my previous post. Has Phil Allison ever designed and wound and tested any of his own OPT's? I doubt it, he's never said he has, and has no pictures at any website to indicate his experience and so he remains inexperienced on this topic unless he spends some time building a few OPTs. My post included some guesses as to what is actually inside a Plitron, or any other decent bass amp OPT. The guess I made of 3,200 turns around a core section of 75mm x 40mm might be on the high side, and perhaps only 3,000 turns are around a section of 65mm x 30mm The Plitron has a o/a size of 152 dia x 89 mm high, so the toroidal core inside the pot must be about 135mm dia and the 65mm x 30mm section allows for a hole dia of 75mm. The build up of copper is thickest in the hole of the toroid, and 3,000 turns of 0.6mm dia primary wire plus insulation plus a secondary would occupy about 2,000sq.mm around the inside of the toroid hole, so the build up would have to be approx 10.6 mm, say 12mm, so where the wire returns up over the ends of the toroid edges the build up would flatten to about 9mm, so the height of the complete item would be item would be 83mm, which would fit into the pot case. The core I mention would weigh about 5 Kgs, and the wire about 1.2 Kgs, so the total of 6.5 Kg allows for the pot and potting mix. I would conclude that I do have some idea what Plitron is doing, and that their efforts constitute a good valid design for a bass amp. Phil Allison insults and belittles everyone who enjoys products like Plitron's products, and all those who like hi-fi, and tube amps by saying:- "** The Turneroid Parrott cannot tell what is actually needed for a bass guitar amp from what is pure wank value for hi-fi masturbators like him." I would like to see Phil Allison quit this group, and stay away, since he has *no* respect for anyone within it. Patrick Turner. vaissue Phil Allison wrote: "Patrick Turner" We all got a laugh when Phil Allison tried to reply on the subject of a toroidal OPT suitable for 300 watts. ** TheTurneroid Parrot is delivering us more of his smelly droppings. Is the small brained Phil Allison going to suggest that Plitron have no clue? ** The Turneroid Parrott cannot tell what is actually needed for a bass guitar amp from what is pure wank value for hi-fi masturbators like him. ............... Phil |
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#60
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"Patrick Turner" Phil Allison insults and belittles everyone who enjoys products like Plitron's products, and all those who like hi-fi, and tube amps by saying:- "** The Turneroid Parrott cannot tell what is actually needed for a bass guitar amp from what is pure wank value for hi-fi masturbators like him." I would like to see Phil Allison quit this group, and stay away, since he has *no* respect for anyone within it. ** I have no respect for the evil Turneroid Parrot - no sane person could possibly have any. The Turneroid tells lies, deliberately misrepresents what others say, posts vile slanders and even criminal treats. The Turneroid is a charlatan and a fraud - even more so and much worse than Andre Jute thinks. ............... Phil |
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#61
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"Chris Berry" wrote in message ...
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 wondering if you might be trying to reinvent an old wheel already perfected & proven, and occasionally available? The 400PS took the practical/portable tube bass head about as far as reasonable, by using 6 x 6550A (KT88 if you like) in AB2 for an easy 400w, and this head will do about 560w with a small mod (by using its 4th OPT winding originally dedicated to NFB). It uses a doubler B+ supply, too, with the 700v you envision. Note that its C- supply is designed to furnish the necessary grid current for AB2 operation. With the iron required the head weighs 84 lbs, so if torroids might get it lower they'd be a plus, but the amp has already been made & proven itself in 30+yrs of service using this tube type, and there is no new ground here. They also come available from time to time, though scarce, in the neighborhood of what you plan to invest in a build (not counting your time & a good roadworthy cab & cosmetics for it, which are missing from your budget). It has also been shown that most ordinary 6550/KT88 toasts or melts in AB2 service at this power level, though using 8 vs 6 would probably solve that at the outset. This is the only advantage I could see for the build you describe, unless waiting for market availability is a problem. If one is winding one's own iron with torroids throughout or isn't weight-conscious, and isn't squeamish about HV (and is experienced in HV construction & never plans to sell or give it away), 2 x 813 might be a better way to go, and they would be more comfortable at this pwr level than 8 little bottles. They have "black plates", toopuke, are inexpensive in the highest quality, and don't need expensive or hard-to-find sockets & cooling hardware like other high-power tubes. A real man's tube, and no one will want to frig with your amp. :-) Your 240v mains make it more doable. I assume you have a truck to carry the necessary spkr cabs for any 400+w tube bass amp to really perform with. If not, this might add $18,000 to the cost. :-) Ken Gilbert has done a lot with the many-little-bottle-monster-bass-amp idea, you may wish to take a look at his site. Different stokes, as they say; where I live, if someone dies with something like this around, they call it "barn trash" and pay a trucker to haul it off... |
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#62
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#64
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Patrick Turner wrote in message ...
Sam Byrams wrote: A cutting head amp has its bass signals very attenuated compared with the 1 kHz reference, so you'd think an OPT with a toroidal core would be OK. This thread is about a bass or guitar amp, and so do they. Look at how skimpy most OPT iron is in many highly-acclaimed amps of this type. It relates to the human ear loudness curve. Please remember this is all about music production and not about reproduction. I have zero experience with winding torroids but no glaring reason has come up so far as to why one might not work as well or better in this application on the basis of freq response (though AFAIK I may not). IMHO the only issue there is whether one wants to experiment with a torroid for possible weight advantage, or just build the thing with stage-proven iron & be done with it. I'd look at several classic Altec designs, the MI200 McIntosh, and the 3000 watt Cincinnati Stadium amp built and thoroughly documented-including wind sheets for the opt-in the IRE journals in the 1950s. Hard to find all that ancient old info, is it not? I have studied the latter & the winding details, and it is a waste of time & OT here. The 3kw job was a class B custom wind (bifilar) using PP 3-1000A's and only suitable for a voice PA in its era and in that singular contract application. The objective was to overcome inherent B crossover notch horrors within a limited freq range & it worked on a on-off basis (and presumeably at exhorbitant contract cost). It was useless outside 400 - 4khz and there is a reason why no other has been built since. Class B is wholly unsuited & irrelevant to *tube* guitar/bass music production due to the impracticality over overcoming notch distortion inherent in the use of any iron subjected to exactly 180 cutoff. They OP isn't building a modulator for AM voice service or a PA with 1954 fidelity standards for sports announcing. Until or unless a better & faster-fluxing magnetic material than iron is around, it will stay that way, and by the time it is, I doubt anyone will still be fooling with tubes for anything but a curiousity. It is also masturbatory to play about with tubes in B & building exotic iron to support them, or resurrecting other ancient high-pwr audio reproduction schemes to likely try with no clue of how they will respond tonally in real-work music production, when AB2 & ordinary hardware has already met or exceeded the need wth ordinary bottles in every way, and is simple to design & build. |
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This thread is about a bass or guitar amp, and so do they. Look at how skimpy most OPT iron is in many highly-acclaimed amps of this type. It relates to the human ear loudness curve. Please remember this is all about music production and not about reproduction. That's a risible argument except in the case of rock and other electric guitar players where tube distortion is explicitly a factor in the sound. In the case of bass (usually-there are exceptions), acoustic guitar,steel guitar, accordion (AFAIK), most organ sounds-possibly excepting R&B/Gospel Hammond Leslie players-electric piano, et al, the "tone" (really timbre) is instrument generated and we do indeed want REproduction. And, remember, Les Paul (the man) never used a guitar amp, he goes straight to the board, if he were to use a guitar amp it would be as a REproducer too. I laugh my ass off when people go off on "that Les Paul sound". Jimmy Page sold a lot of Pauls with his Tele: the only LPs that Les himself would have were the seventies low impedance models, which are unwanted even in today's vintage penis size worship market. I have zero experience with winding torroids but no glaring reason has come up so far as to why one might not work as well or better in this application on the basis of freq response (though AFAIK I may not). IMHO the only issue there is whether one wants to experiment with a torroid for possible weight advantage, or just build the thing with stage-proven iron & be done with it. I'd look at several classic Altec designs, the MI200 McIntosh, and the 3000 watt Cincinnati Stadium amp built and thoroughly documented-including wind sheets for the opt-in the IRE journals in the 1950s. Hard to find all that ancient old info, is it not? I have studied the latter & the winding details, and it is a waste of time & OT here. The 3kw job was a class B custom wind (bifilar) using PP 3-1000A's and only suitable for a voice PA in its era and in that singular contract application. The objective was to overcome inherent B crossover notch horrors within a limited freq range & it worked on a on-off basis (and presumeably at exhorbitant contract cost). In fact it was the cheapest alternative then available. It was useless outside 400 - 4khz and there is a reason why no other has been built since. Class B is wholly unsuited & irrelevant to *tube* guitar/bass music production due to the impracticality over overcoming notch distortion inherent in the use of any iron subjected to exactly 180 cutoff. Those Macs didn't work at all, did they? They OP isn't building a modulator for AM voice service or a PA with 1954 fidelity standards for sports announcing. Until or unless a better & faster-fluxing magnetic material than iron is around, it will stay that way, and by the time it is, I doubt anyone will still be fooling with tubes for anything but a curiousity. It is also masturbatory to play about with tubes in B & building exotic iron to support them, or resurrecting other ancient high-pwr audio reproduction schemes to likely try with no clue of how they will respond tonally in real-work music production, when AB2 & ordinary hardware has already met or exceeded the need wth ordinary bottles in every way, and is simple to design & build. Bull****. It would be easy enough to borrow a Big Mac or Altec, hook it to a bass cab, get a preamp, and plug in. It has been done. I've heard it. The 1570B with a replacement opt is known to kick ass as do (the stock) MI200, the MC75/275, MI3500, and one or two other monsters of yore. But do the experiment yourself, don't dry-lab your way through life. The stadium amp had extremely limited bandpass to keep the weight of the OPT down and to provide speech limiting needed anyway, as does the 1570B. This same design was built in a lot of different sizes (with far wider bandpass) and in fact was an attempt-largely but not wholly successful-to do the same thing Frank, Gordon and Sid did without fouling their patents. (Now long dead). The faults of Class B tube amps-and the solid state ones too-have always been at very low output levels, and while no wholly sufficient mitigation exists, you design for AB2-to-B2 , which in fact is what Fender tried for in the PS400 and Mac reasonably succesfully implemented in every amp they built (save the MA230), as did Julius Futterman et al, as did Wiggins with his Circlotron. |
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