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#41
Posted to rec.audio.tubes
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In article ,
"Iain Churches" wrote: "Patrick Turner" wrote in message ... Andre Jute wrote: Iain Churches wrote: c) this active load cathode follower. In listening tests, people chose C. Shh! Allen Wright will come demand a royalty. That's the big secrets his guru passed on to him, to use cathode followers and to tie the wright (sic -- heh-heh!) currents down tight. I think perhaps you could be guessing about what is in Iain's preamp. He has avoided giving us a schematic. He started off saying it was generic 6SN7 used as a gain stage followed by cathode follower, as Tremaine may have described in 1963, but then talks about listening tests using vastly fifferent topolgies, and just what is in the box is a complete mystery. Tremaine 4th edition dates from 1975. No mystery Patrick. I stated clearly that it is an active load cathode follower, which was chosen after comparison with a mu-follower and a cascode. I have no schematic drawn. It can be found in any one of a dozen books Perhaps he don't want to give away copyable secrets. Copyable secrets? LOL. People have been using this topology for 50 years:-)) It was used in line and distribution amps in studios and broadcast everywhere. I can remember seeing racks and racks of 'em. OK, the circuit was used in studios and broadcast everywhere, is the circuit anything like the 12BH7 output stage in this device? http://www.waltzingbear.com/Schemati...Urei_LA-2A.JPG Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#42
Posted to rec.audio.tubes
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On Apr 11, 10:07 am, John Byrns wrote:
In article . com, "Peter Wieck" wrote: On Apr 10, 4:20 pm, "Iain Churches" wrote: "Peter Wieck" wrote in message ups.com... On Apr 10, 3:51 am, "Iain Churches" wrote: http://www.kolumbus.fi/iain.churches...ier/252.02.jpg Wowsers... looks vaguely like: http://www.radfordaudio.co.uk/ mid-page right. Is yours the chicken or the egg? How do you tell, which came first, the chicken or the egg? My wild guess would be that Ian's amp was the "egg". Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ The chicken is the egg's excuse for another egg. Peter Wieck Wyncote, PA |
#43
Posted to rec.audio.tubes
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In article ,
"Ian Iveson" wrote: Iain: http://www.kolumbus.fi/iain.churches/Preamp/203A.html It's a joint effort together with my pal Markus. He is a very skilled metal worker and made the casework, and also laser-cut the stainless steel top grille. We decided to do as much possible ourselves. Any comments would be of interest. Nice power plugs. Screws holding the grill spoil the plot IMHO, more than your accustomed eyes might suggest. I think you have nailed what bothered me about the grilles. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#44
Posted to rec.audio.tubes
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In article ,
"Iain Churches" wrote: I have received as many replies and comments re this preamp, by e.mail direct as I have on the NG, and people off-list are usually much more helpful and constructive. The emails are doubtlessly helpful and constructive to you, but they are useless to the rest of us who would like to learn something from the various projects presented on this forum. Unfortunately there are those who don't like to share, perhaps they lack confidence in their ideas, and revert to email. Both the best and the worst comments seem to be reserved for email. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#45
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Andre Jute wrote: Patrick Turner wrote: Andre Jute wrote: Iain Churches wrote: c) this active load cathode follower. In listening tests, people chose C. Shh! Allen Wright will come demand a royalty. That's the big secrets his guru passed on to him, to use cathode followers and to tie the wright (sic -- heh-heh!) currents down tight. I think perhaps you could be guessing about what is in Iain's preamp. He has avoided giving us a schematic. He started off saying it was generic 6SN7 used as a gain stage followed by cathode follower, as Tremaine may have desribed in 1963, but then talks about listening tests using vastly fifferent topolgies, and just what is in the box is a complete mystery. Perhaps he don't want to give away copyable secrets. This is not very nice. At r.a.t we are supposed to be a free tube-craft information outlet for the WWW. I have 18mB at a website and page after page of schematics which anyone is free to use. But Allan Wright's special super cathode follower is only just that, and whether it dramatically increases sonic heaven's enthralling qualities is a moot point. Patrick Turner RAT is a voluntary association. Everyone publishes what he likes in whatever form he likes, and whatever he chooses to share with us is a favour. We have no right to demand any more. Indeed we have no rights to demand, and we won't, well, not at gun point. So we are left with time to ask, persuade or cajole. That is about all I have time for, and if what is asked for does not turn up, so be it, there are plenty of other things to move along to. Your demand in another post that anyone who wants to post an amp on RAT should document it fully, *and be prepared to defend it*, encourages exactly the sort of adversarial procedure that has made RAT the sewer it is. Full presentation of the facts about what one has done might have the opposite effect, and lead to less adversarials. I don't believe it ever has been possible during the last 3 million years of human evolution for people not to be adversarial, and conduct challenging discussions. Such heated discussions have led to where there might be game was when it came time for a hunt, or how best to go about it, and how best to divide the hunt results, and who the leader of the next hunt should be. There has always been a world where people fight over some darn thing. Humans have the most unenviable record for fighting amoung themselves and it seems to be a function of warped intelligence, until you realise how warrior mode was related to survival, and in the hunter gatherer world, you have to kill the next tribe if they steal water or game on your side of the mountain. When people became agricultural and civilised, they had to defend themselves against raiders. For hundreds of millions of years the dinosaurs fought amoung themselves, the old animal rules of tooth and claw, and all about survival and who you get to ****. How come that lot of lizards didn't evolve an intelligent reptile? Were they too cunning to let themselves drift to intelligence? Well, if they had evolved, we wouldn't be here. So in fact there is "fight" in all species, even amoung trees in a forest for dominance, and its always been like this. So our traits go back to the first organic molecule, many hundreds of millions of years. Jesus came with a message of love, compassion, and hope and forgiveness. Most have ignored him; how do you change human nature that took 400 million years to form in 3 years? Jesus needed to stay many more years to get anywhere against the idea of an eye for an eye, and no forgiveness, and all that hard old **** in the Old Testament....... Did not Jesus find a rabble to contend with? There are many humans who actually like sewers, like rats do. I personally don't like wars, sewers or rats, but I would fight for truth and undertstanding, and the abolition of BS wherever its level tries to rise above the gumboots. I wonder if amoung the millions of other planets where life did evolve, is still evolving, or will evolve in future there are planets where competition does not evolve. Would a planet based on caring and sharing and never a harsh word be one that could evolve? And don't tell me such a place would be feminine, I only have to think of Margaret Thatcher to believe it entirely probable that females were the first to develop weapons to whomp a bad man when he was asleep, and certainly females can be fiesty, and live by the idea that the end justifies the means. Patrick Turner. Andre Jute |
#46
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Andre Jute wrote: Phil Allison wrote: "Andre Jute" I know, Iain. I was making a joke about the way Allen in his book makes it sound as if his guru received the cathode follower and the constant current source from the finger of God himself. ** Well, as a life long Scientologist - he would imply that, wouldn't he. Only the "God" in question was his implanted, operating Thetan. Anyway, you're not ready to be an audio guru yet. You're too young and you have too much hair. Allen Wright and Holger Stein and Dieter Ennemoser and I decided long ago that the only people who are qualified to build good audio equipment are over fifty and going light on top -- like us. ** Whaaaaattt ??? Kiwi ex pat Scientologist " Alien " Wright was going very thin on top way back in 1980. Naw, he didn't see the light about the best designers being over fifty until he was himself over fifty... The minute he explained it to me, I saw it too, probably because I'd just turned fifty. Didn't Allan discover tubes rather late after spending all that time with HP working with SS? Like all passionates, he's a mix of ideas, some good, some bad. Looked a like some demented woman's idea of Yul Brynner. I know, cos I briefly worked for the shonky idiot and met his various " ladyfriends ". LOL !! Allen's a guy of sudden enthusiasms, which is a kind way of saying eccentric. I wonder how he goes down in Germany. Didn't the German Government conduct and win a major court case against Scientology? I decided Scientology wasn't for me about as soon as I became aware of it, and it seemed to be just another looney belief system amoung so many that one does well to stay clear of. While giving thought about Allan being a scientologist in Germany, one wonders how much if any harm he does to others under the German situation and history. Some ppl must have what appears to me to be an irrational need to believe in all sorts of things I think are BS. They are quite unhappy without such beliefs, and how it is that so many people with logical and genuinely scientific minds can spend time being illogical and irrational is beyond me. A few of them know something rather than nothing about tube audio, and that is the most relevant thing to me. I am not offended by their religion, sexual orientation, skin colour, voting habits, criminal record, how much filthy money they have, or their poor dress sense. There are some very obvious false notions about concerning audio; Shakti Stones were a classic example of in-your-face quackery. But in life as we look outward broadly, there are to be seen many more and far worse odious false notions presented to us day to day than some galloot trying to sell us a few rocks to make the sound better, or someone telling a story about using tubes, and including a modicum of BS. Patrick Turner. ....... Phil Thanks for the giggle, Phil. Andre Jute Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ "wonderfully well written and reasoned information for the tube audio constructor" John Broskie TubeCAD & GlassWare "an unbelievably comprehensive web site containing vital gems of wisdom" Stuart Perry Hi-Fi News & Record Review |
#47
Posted to rec.audio.tubes
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"John Byrns" wrote in message ... In article , "Ian Iveson" wrote: Iain: http://www.kolumbus.fi/iain.churches/Preamp/203A.html It's a joint effort together with my pal Markus. He is a very skilled metal worker and made the casework, and also laser-cut the stainless steel top grille. We decided to do as much possible ourselves. Any comments would be of interest. Nice power plugs. Screws holding the grill spoil the plot IMHO, more than your accustomed eyes might suggest. I think you have nailed what bothered me about the grilles. The user has to be able to remove these, if tube replacement is required. The screws are cap-head, and so can also be removed without tools if required. They could easily be replaced by a low profile cheese-head screw, or even countersunk. Regards Iain |
#48
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"Ian Iveson" wrote in message . .. Iain: http://www.kolumbus.fi/iain.churches/Preamp/203A.html Nice power plugs. Do you mean the DC connectors? Screws holding the grill spoil the plot IMHO, more than your accustomed eyes might suggest. The rest of the panels are fixed with tamper-proof screws. Only the grille has cap- head screws which can be removed with a hex key or by finger, (if the user has no tools) to change the tubes. Things I build for myself, I try to style like weird science, rather than engineering from the days of Edison, and your use of a double skin chassis is well OTT. Have you ever talked to people to ask what they think of current design? The use of the copper inner chassis means that the inner parts of the amp can be pre-assembled. This was something that was widely done in analogue studio equipment. As something styled for market, it would be interesting to know which. These days, reliability and precision are hardly associated with weightiness. People have learned the opposite. Hmm. Interesting. I gained a totally different impression when talking to dealers, musicians, and people interested in high end audio. It seems that PQ (perceived quality) is regarded as important. Look at Border Patrol, or Audio Note. Chunky is out, svelte is in, for the longer view. It would be easy to copy any of the above. Don't you think it is interesting to do something a little different? We did, so we have:-) Regards Iain |
#49
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"Peter Wieck" wrote in message ups.com... On Apr 10, 4:20 pm, "Iain Churches" wrote: "Peter Wieck" wrote in message ps.com... On Apr 10, 3:51 am, "Iain Churches" wrote: http://www.kolumbus.fi/iain.churches...ier/252.02.jpg Wowsers... looks vaguely like: http://www.radfordaudio.co.uk/ mid-page right. Is yours the chicken or the egg? More than *vaguely like*:-) It's an STA25 MkII. I updated it to Mk III later. But it could have been anything, the layout is so sensible. While at Decca, we had close contact with Radford, and I managed to get a complete set of iron from them. Regards Iain |
#50
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"John Byrns" wrote in message ... In article , "Iain Churches" wrote: I have received as many replies and comments re this preamp, by e.mail direct as I have on the NG, and people off-list are usually much more helpful and constructive. The emails are doubtlessly helpful and constructive to you, but they are useless to the rest of us who would like to learn something from the various projects presented on this forum. Unfortunately there are those who don't like to share, perhaps they lack confidence in their ideas, and revert to email. Both the best and the worst comments seem to be reserved for email. Hello John. Many of those who keep in touch by e.mail are former subscribers to this and other Usenet groups. Most of them can be found on closed groups to which the lunatic fringe (in our case PA and AK) are denied access. The discussion on such fori is well-informed and constructive. Pics and schematics can be posted. I have access to two such groups, which are divided by general topic into several sub groups, broadcast, studio practice, studio engineering, music performance, audio teknik (which includes tube amps) etc etc There are sometimes a total of 200 posts, all on topic in 24 hrs. No wonder so many eschew the bar-room brawl that RAT has become. Iain PS Just had a mail from a pal who read your post. He says "Closed groups are like large condenser microphones. The only people who don't like them are those that do not have access to them":-) |
#51
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"John Byrns" wrote in message ... In article , "Iain Churches" wrote: No mystery Patrick. I stated clearly that it is an active load cathode follower, which was chosen after comparison with a mu-follower and a cascode. I have no schematic drawn. It can be found in any one of a dozen books The cathode follower part sounds straight forward enough, but the "active load" part could be anyone of a number of things. Is the circuit what I think is called a "White" cathode follower? The White CF is similar, except that the anode of the bottom triode and the cathode of the upper triode are usually at the same potential. The grid of the top triode is biased by a pair of resistors from the B+ to ground, with the junction of these two Rs connected to the grid. On the ALCF the grid of the lower tube is biased in this way. The anode of the lower tube and the cathode of the upper tube are separated by a resistor of about 1k2 to give a differential of about 2V between them. 1M is then connected from anode 1 to grid 2 for bias (rather like the mu-follower) Best regards Iain |
#52
Posted to rec.audio.tubes
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"Andre Jute" wrote in message ups.com... Iain Churches wrote: "Andre Jute" wrote in message ups.com... Iain Churches wrote: This is not the Wright Schematic, but the generic active load cathode follower which can be found in many textbooks. I know, Iain. I was making a joke about the way Allen in his book makes it sound as if his guru received the cathode follower and the constant current source from the finger of God himself. :-) Yes, I got the joke:-) Anyway, you're not ready to be an audio guru yet. You're too young and you have too much hair. Old enough, but I do still have a full head of hair, and weight in at 80kgs! Allen Wright and Holger Stein and Dieter Ennemoser and I decided long ago that the only people who are qualified to build good audio equipment are over fifty and going light on top -- like us. And Peter Walker:-) I also teach recording arts to young musicians mainly classical players, at Academy level. It is important for them to understand what goes on and what is expected of them in the recording studio environment. Most never get studio gigs because they have no experience. And they can't get experience without doing some gigs! It's very highly paid work, and so orchestral agents book only the top players. Back in the 70s, string sections on pop records were common. These days, real strings are seldom used, or real drums for that matter, so anyone who knows how to set up a string section or a rock or jazz kit has achieved guru status:-)) Best regards Iain |
#53
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"Andre Jute" wrote in message ups.com... Patrick Turner wrote: Andre Jute wrote: Iain Churches wrote: c) this active load cathode follower. In listening tests, people chose C. Shh! Allen Wright will come demand a royalty. That's the big secrets his guru passed on to him, to use cathode followers and to tie the wright (sic -- heh-heh!) currents down tight. I think perhaps you could be guessing about what is in Iain's preamp. He has avoided giving us a schematic. He started off saying it was generic 6SN7 used as a gain stage followed by cathode follower, as Tremaine may have desribed in 1963, but then talks about listening tests using vastly fifferent topolgies, and just what is in the box is a complete mystery. Perhaps he don't want to give away copyable secrets. This is not very nice. At r.a.t we are supposed to be a free tube-craft information outlet for the WWW. I have 18mB at a website and page after page of schematics which anyone is free to use. But Allan Wright's special super cathode follower is only just that, and whether it dramatically increases sonic heaven's enthralling qualities is a moot point. Patrick Turner RAT is a voluntary association. Everyone publishes what he likes in whatever form he likes, and whatever he chooses to share with us is a favour. We have no right to demand any more. Your demand in another post that anyone who wants to post an amp on RAT should document it fully, *and be prepared to defend it*, encourages exactly the sort of adversarial procedure that has made RAT the sewer it is. Andre Jute Andre, as a long term poster here, I am sure you have noticed how many interesting people have abandoned this NG and Usenet in general. After the demise of Pinkerton, there was some hope that things would improve. As I mentioned in a reply to Patrick, I posted this link to relieve the monotony of Arny's OT drivel, and Phil's autistic cut-and-paste. Perhaps I should not have bothered:-) Best regards Iain |
#54
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"John Byrns" wrote in message ... In article , "Iain Churches" wrote: Removing the stainless steel grille to change the tubes reveals what appears like an empty compartment with just the tubes and the tube bases set horizontally into a 4mm bulkhead. There is a "false floor" under which the cable harness runs to the input selector and switched attenuators at the front. Wouldn't it be better to eliminate the false floor and provide a steel grille on the bottom to provide improved air circulation for better cooling? John. There are cooling slats in the base plate. The air is vented through the lower edges of the bulkhead. Maybe I shouldn't even suggest that as the steel grille on top is the one design element that doesn't look quite right to my eye, although I am not sure why. Perhaps the pic does not do it justice? Most people who have seen the unit are of the opinion that the laser etched grille together with the stainless steel dials sets off the whole appearance of the unit beautifully. Best regards Iain |
#55
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"Patrick Turner" wrote in message ... Eventually, we will coax a schematic from the man, and why the noise is so high. Hello Patrick, I will draw it when I have time. In actual fact we have established that the noise is not high, but my method of measurement erroneous. As soon as this unit comes back from a demo tour, my pals at Swedish Broadcast have promised to measure the noise floor. My best AC voltmeter (Marconi) has 300µV as the lowest range, so perhaps the resolution is not good enough to measure this unit accurately. Best regards Iain |
#56
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In article ,
"Iain Churches" wrote: "John Byrns" wrote in message ... For the first time in a long time I have to agree with Phil, something just doesn't add up here. By the way, where did these specs. come from, did I miss a link on Ian's page? Morning John. Last night, I listened to Shostakovich 2nd Symphony (Op 14) the excellent interpretation by Gothenburg Symphony Orchestra conducted by Neeme Järvi. I turned up the level so that I could not stay in the room. Then, using the remote, I put the CD player onto pause, and returned to my listening chair. There was silence, so I think the performance of the preamp is as it should be. There are two possibilities here. a) The pair of tubes I have fitted (RCA cleartops) are noisy (possible but unlikely) b) My noise measurement methods are incorrect (much more likely) The preamp has been packed up now, and shipped off to the first of several people who want to hear it. So I shall not be able to investigate further for a while. What sort of a SNR (A weighted) should I expect from an active loaded cathode follower? Hi Iain, There are two issues here, first what sort of unweighted SNR you should expect, and second what effect will A weighting have on the SNR. Taking the A weighting issue first, I would think the effect would depend on what the dominant noise source is in your preamp, is it noise due to random processes in the components used, or is it due to line frequency harmonics from the power supply? How was the input terminated for the SNR measurements? With respect to the noise you should expect, assuming all the line frequency related noise has been dealt with, we should be able to calculate that. Unfortunately I don't do those calculations on a daily basis, so I would have to root around in my files to find the relevant formulas. Perhaps while I am searching, someone else has the necessary formulas right at their finger tips, and can provide the answer more quickly than I ccould? When Phil said your output noise level was too high I started wondering could he be correct? My first thought was my "Power Amplifier Without Power Transformer", which uses a 12SN7 driver stage. This amplifier has an output noise level greater than 80 dB below 1 Watt output, without negative feedback. I thought I would do a quick calculation to estimate what the noise level at the output of the 12SN7 stage might be. I did the calculations with a calculator, and without writing anything down, and found the noise level at the output of of the 12SN7 to be in the same general ballpark as your preamp. This did not seem to be a promising result relative to your preamp, as my PAWPT uses a series heater string across the power line, and a half-wave rectifier directly off the power line, with the output stage B supply filtered only by the main filter capacitor, not necessarily a recipe for low noise. I will have to run through the calculations again, writing down the steps, to be sure I didn't skip a digit somewhere. Another way to look at the preamp output noise is to consider what would happen if you feed a 120 uV noise source into a power amp with a typical gain of 20X. For an 8 Ohm load that would give an output noise level only about 61 dB below 1 Watt, not exactly a top rank result. Only the actual calculation, which I will try to do later, will tell us what sort of noise level you should expect. I would hope for 40 uV of noise at worst, and would prefer less than 12 uV of noise, although I don't know if that is possible. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#57
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Comments were interesting. Most people were averse to the ubiquitous silver anodised equipment that seems to adorn every hi fi shop. Most preferred filament indicator lamps to LEDs (when someone bothered to show them the difference) That's just styling decoration, which has no effect on the sound (unless someone does something that removes shielding to a sensitive part of the circuit, or such). But I do admit to not liking the current fashion that has the tubes sticking outside the "cabinet" without any metal cage or such to enclose them. Tubes get hot, and I don't like burning myself on them... But a cage should have lots of holes for ventilation, so you still get to see the cool looking heater glow! Most preferred engraved panels to silk screen. All preferred our laser etched dials to either of the other two possibilities. I prefer the silver box over a black box, if for the only reason that I can actually see the black markings on the silver panel a lot better than white (or gray) markings on a black panel. I have a few black boxes, and I always have to look closely at the markings to see which button to press. PITA! |
#58
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Eventually, we will coax a schematic from the man, and why the noise is so high. I will draw it when I have time. Please understand that the most valuable document in a DIY forum or NG is the schematic circuit diagram. Otherwise we won't really comprehend exactly what you did. Photos of the completed boxes are pretty, but don't really tell us much. |
#59
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How was the input terminated for the SNR measurements? I'm no expert in SNR measurement methods, but I'd think that the input jack should have a resistor to ground, and the value of that resistor be the same as the Thevinan equivalent impedance of the expected sources. Like 47K if it's a phone cart, but this isn't a phono preamp. And other sources' impedances are all over the map, so we should pick something that makes for "worst case" conditions. Probably a higher resistance value. 100K? |
#60
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"Iain Churches" As soon as this unit comes back from a demo tour, my pals at Swedish Broadcast have promised to measure the noise floor. My best AC voltmeter (Marconi) has 300µV as the lowest range, so perhaps the resolution is not good enough to measure this unit accurately. ** Hey ****wit. If you wanna measure low level noise - first you gotta * amplify * it !!! A flat response gain stage, with one or two op-amps, will provide 100 or even 1000 times gain. Then you attach an audio band filter and finally a wide band millivolt meter. ......... Phil |
#61
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"robert casey" I'm no expert in SNR measurement methods, but I'd think that the input jack should have a resistor to ground, and the value of that resistor be the same as the Thevinan equivalent impedance of the expected sources. ** For a CD player or similar, that is about 250 ohms. But even that is pointless, as all active sources have their own output noise - way above that of the impedance alone. Like 47K if it's a phone cart, ** ********. A phono cartridge in an inductance, so has a source impedance that rises with frequency. A 47 kohm resistor is fitted to the pre-amp as a LOAD for that cartridge. With NO cartridge connected, the noise level from a typical phono pre-amp is 10 to 20 dB higher than when one is connected. Are you so asinine you have never noticed this ??? And other sources' impedances are all over the map, ** No they are not - you bull****ting ass. The expected source are all active and have very low impedances. ........ Phil |
#62
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Iain Churches wrote: "John Byrns" wrote in message ... In article , "Iain Churches" wrote: I have received as many replies and comments re this preamp, by e.mail direct as I have on the NG, and people off-list are usually much more helpful and constructive. The emails are doubtlessly helpful and constructive to you, but they are useless to the rest of us who would like to learn something from the various projects presented on this forum. Unfortunately there are those who don't like to share, perhaps they lack confidence in their ideas, and revert to email. Both the best and the worst comments seem to be reserved for email. Hello John. Many of those who keep in touch by e.mail are former subscribers to this and other Usenet groups. Most of them can be found on closed groups to which the lunatic fringe (in our case PA and AK) are denied access. The discussion on such fori is well-informed and constructive. Pics and schematics can be posted. I have access to two such groups, which are divided by general topic into several sub groups, broadcast, studio practice, studio engineering, music performance, audio teknik (which includes tube amps) etc etc There are sometimes a total of 200 posts, all on topic in 24 hrs. No wonder so many eschew the bar-room brawl that RAT has become. Iain PS Just had a mail from a pal who read your post. He says "Closed groups are like large condenser microphones. The only people who don't like them are those that do not have access to them":-) I must be the exception. I have access to a bunch of little secret groups and won't take part in any of them. I have visted some of these groups but rarely felt a need to reply to anything I read, or I would have shown them more interest. But I only get to talk to maybe one or two people who often don't know very much and who hate their pet theories being challenged. I'd much rather post to the widest pssible audience. I would say that there are a large number of people in the minor groups who keep their eye on what is said here, but are afraid to take part because they would just get treated as fools or idiots. But because this is an unmoderated group, ie, is like a beach without a shark net, one has to be concise and truthful and knowledgeable to take a swim in these waters, and be quite prepared to proove what you say, and say a lot in explanation, not just some dumb one liner. So there is an imperative to bring one's technical competence up to a certain level BEFORE trying to discuss matters with authority, and unless you have studied and done your homework, ridicule greets you if you come here unprepared. All these little groups have HORRIBLE access paths and their site all don't work as easy and simply as a usernet group, with the groups listed in my inbox, and one click brings me to the day's postings with header titles, and I can review everything posted for the recent past. Another click brings me whatever post i want to reply to. one more click is for reply, and I get a full page to type into, not some STOOPID 100mm x 50mm section of the screen. My intelligence is insulted by the outright display of incompetence promulgated by all these little discussion groups; they'd like me there, I have been invited, but they want me to eat a **** sandwich before and while I take part. They know where I am, and where I post. Why can't they be real men and expose their ideas to the whole world without fear like I do? They don't like the heat of being challenged, they expect to get away with believeing their own BS, and most have no passion about anything. I am not going to waste my precious time yabbering at dumbos via rottenly set up group formats. I wouldn't mind being able to take part, but its all got to be easier to use. Patrick Turner. |
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Like 47K if it's a phone cart, ** ********. A phono cartridge in an inductance, so has a source impedance that rises with frequency. A 47 kohm resistor is fitted to the pre-amp as a LOAD for that cartridge. With NO cartridge connected, the noise level from a typical phono pre-amp is 10 to 20 dB higher than when one is connected. Are you so asinine you have never noticed this ??? :-) Well, then, maybe I should use an actual phono cart (housed inside a shielded box to avoid external noise pickup). Been a while since I've messed with record players. And other sources' impedances are all over the map, ** No they are not - you bull****ting ass. The expected source are all active and have very low impedances. :-) Okay, but I was thinking of sources like a vintage vacuum tube FM tuner, which tend to have higher output impedances. (wouldn't be suprised to have having had another brain fart, I've done it before...) :-) |
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"Iain Churches" wrote in message . fi... Andre asks what all the tubeheads are doing. You can see what this tubehead is doing at: http://www.kolumbus.fi/iain.churches/Preamp/203A.html It's a joint effort together with my pal Markus. He is a very skilled metal worker and made the casework, and also laser-cut the stainless steel top grille. We decided to do as much possible ourselves. Any comments would be of interest. Regards to all Iain Did Marcus and you do all the metal work in your lab or did he do any of it at his work place? If done at your lab, that leads me to another question .... Knowing little about metal work, can an individual buy all the needed equipment (perhaps you can list all the needed equipment) and diy or is this strictly left to the professional metal worker? I bet Marcus doesn't know Greek or Latin. ;-) Cordially, west |
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Iain Churches wrote: "Patrick Turner" wrote in message ... Eventually, we will coax a schematic from the man, and why the noise is so high. Hello Patrick, I will draw it when I have time. In actual fact we have established that the noise is not high, but my method of measurement erroneous. As soon as this unit comes back from a demo tour, my pals at Swedish Broadcast have promised to measure the noise floor. My best AC voltmeter (Marconi) has 300µV as the lowest range, so perhaps the resolution is not good enough to measure this unit accurately. Best regards Iain To measure noise below 300uV, you need a low noise amplifier to raise its level to work a meter or display it on a CRO or both. So you need to make a wide band amp, at least 10Hz to 20kHz with gain of up to 1,000 for noise measurements, but gain able to be varied between say 10 and 1,000. So if noise = 3uV, it is amplified to 3mV after the amp, and able to be measured/displayed by gear you have already. Its so darn easy, but takes time and understanding, and you are short of both. There are many opamps good enough to raise a small signal to a larger one for measurement and without adding any substantial noise&distortion of their own. I became frustrated with my limitations on what I could measure while I taught myself to answer the myriad of questions I asked of myself in years spent locked in my shed before I dared to go online where I might be ridiculed for not doing/understanding very much. So amoung the simple test gear I did build was a millivolt meter with 6 ranges 1mV to 1,000Vrms with 2Hz to 1MHz bandwidth. They are based on discrete solid state devices and opamps, no need for tubes. A wide band amp, 10Hz to 30MHz with two 2N222 with gain of 20 raises signals a bit if I need to. For measuring noise in input tubes, ie, establishing what the grid input noise is of any given sample triode, a 20Hz to 20kHz 3 stage tube amp with max gain = 1,600 is used. Its like a very quiet microphone amp. These are not pretty, but have worked fine for 10 years so far, and building them taught me a heck of a lot. I expect you'll do similar if you really want to learn something. When something you design yourself doesn't work, you have to learn more and apply the knowhow until it works better than the text books say it should. Then you proove that to yourself. You should then be able to proove to others the method behind the madness is all OK. Then you have arrived. If you have not done exercizes like the ones I have outlined, you can't do much except copy everyone else, and hope for the best, and put up with lots of your own mistakes. I have posted previously on noise and its measurement here at r.a.t Were you asleep? Did it all go in one ear and out the other? Noise should be measured with the gain turned up and input grounded. It should be described as figure without any signal present. A normal well chosen 6DJ8, 6CG7, perhaps 6SN7, 12AY7, and many others should have no more than 2uV at the grid when grounded. It is generated by the equivalent input resistance which is a figure for any device and you have yet to comprehend such technical issues. But suppose you have a common cathode mode 6CG7 with well bypassed cathode, ( 2k plus 2,200 uF ), RL = 50k, then at 4mA for Ia, perhaps gain = 16. You want to test its noise. The grid is taken to ground with a lead not exceeding 25mm. DC is used on the heater to avoid hum, which may well be much above the hiss, or wide band noise we wish to measure. If there is 1uV of hiss noise at the grid, you get 16uV noise at the anode, and when amplified by a subsequent tube amplifier of similar tubes the noise at the anode of the tube under test will well dominate the measurements because noiase voltages when added are the square root of the sum of voltages squared, something else you need to know. So when two cascaded stages of 6SN7 are added after the DUT tube, the 16uV is amplified 256 times to 4,096uV, or 4.1mV, and easily measured or seen. Hum will perhaps obscure what noise you are measuring, so you MUST specify what sort of noise it is that you are measuring. Is the 120uV of noise from your CF "preamp" hum? or is is wide band hiss, like pink noise? Technically, what you have built isn't a preamp, its an integrated buffer, because it does not have any gain, and so amplifies nothing. Therefore if the grid uput noise was 1uV, the cathode output should also be 1uV Even at 1mV of output signal the SNR would be -60dB, and at a volt of output SNR should be -120dB. In practice this is not all that easy to achieve. But it is where competent designers aim for. We all look forward to a schematic of your latest creation. In another of your posts, your verbal explanations about the schematic to Mr Byrns were about as clear as a beer bottle full of mud, and if you do attempt to explain a schematic in words in future, please show more respect to your fellow group members with more concise terms, double check what you have said, make it simple and easy and unambiguous, to avoid us wasting so much of our precious time to de-cyphering WTF you have tried to say, and getting knowhere. Patrick Turner. |
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Iain Churches wrote: "John Byrns" wrote in message ... In article , "Iain Churches" wrote: No mystery Patrick. I stated clearly that it is an active load cathode follower, which was chosen after comparison with a mu-follower and a cascode. I have no schematic drawn. It can be found in any one of a dozen books The cathode follower part sounds straight forward enough, but the "active load" part could be anyone of a number of things. Is the circuit what I think is called a "White" cathode follower? The White CF is similar, except that the anode of the bottom triode and the cathode of the upper triode are usually at the same potential. The grid of the top triode is biased by a pair of resistors from the B+ to ground, with the junction of these two Rs connected to the grid. On the ALCF the grid of the lower tube is biased in this way. The anode of the lower tube and the cathode of the upper tube are separated by a resistor of about 1k2 to give a differential of about 2V between them. 1M is then connected from anode 1 to grid 2 for bias (rather like the mu-follower) Best regards Iain Unfortunately, I have no idea what Iain is talking about at all. Maybe Iain doesn't know either. Patrick Turner. |
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In article ,
"Iain Churches" wrote: "John Byrns" wrote in message ... In article , "Iain Churches" wrote: No mystery Patrick. I stated clearly that it is an active load cathode follower, which was chosen after comparison with a mu-follower and a cascode. I have no schematic drawn. It can be found in any one of a dozen books The cathode follower part sounds straight forward enough, but the "active load" part could be anyone of a number of things. Is the circuit what I think is called a "White" cathode follower? The White CF is similar, except that the anode of the bottom triode and the cathode of the upper triode are usually at the same potential. The grid of the top triode is biased by a pair of resistors from the B+ to ground, with the junction of these two Rs connected to the grid. On the ALCF the grid of the lower tube is biased in this way. The anode of the lower tube and the cathode of the upper tube are separated by a resistor of about 1k2 to give a differential of about 2V between them. 1M is then connected from anode 1 to grid 2 for bias (rather like the mu-follower) OK, Thanks, I think I understand. The bias sounds like it is done the same way as the circuit at the link I posted. It is not clear from your description if the bottom triode serves simply as a passive load for the cathode follower, or if a signal is applied to the grid of the lower triode making it an active load? Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
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In article ,
"Iain Churches" wrote: "John Byrns" wrote in message ... In article , "Iain Churches" wrote: Removing the stainless steel grille to change the tubes reveals what appears like an empty compartment with just the tubes and the tube bases set horizontally into a 4mm bulkhead. There is a "false floor" under which the cable harness runs to the input selector and switched attenuators at the front. Wouldn't it be better to eliminate the false floor and provide a steel grille on the bottom to provide improved air circulation for better cooling? John. There are cooling slats in the base plate. The air is vented through the lower edges of the bulkhead. Maybe I shouldn't even suggest that as the steel grille on top is the one design element that doesn't look quite right to my eye, although I am not sure why. Perhaps the pic does not do it justice? Most people who have seen the unit are of the opinion that the laser etched grille together with the stainless steel dials sets off the whole appearance of the unit beautifully. Yes, it is very beautiful, especially the dials, except the screws that hold the grilles on are a sort of discordant note, I would prefer that they were recessed, but that is just one man's opinion. Absolute perfection is difficult to achieve. Speaking of perfection, did you ever consider building a matching equalizer to go with the preamp? Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#69
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"Patrick Turner" wrote in message ... I must be the exception. I have access to a bunch of little secret groups and won't take part in any of them. I think you are mistaken Patrick.The groups to which you refer are moderated but not closed groups. That's a totally different thing altogether. Closed groups, for example the broadcast and recording group to which I have access, are used by professionals. If they are not members of the university, institute or company which runs the group, they are there strictly by invitation only. Your are correct in saying that people do keep an eye on RAT. Recruiting to closed groups is not uncommon, and I have never met anyone who has refused the invitation:-) You bump into lot of familiar and respected names. Have you ever wondered why, with the exception of yourself, no other professional audio designer or manufacturer has a presence here? Regards Iain |
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Well I,ve read all the posts about your little project, And it does look the part, At least you have used proper wood, and not MDF with plastic veneer. tell me it's proper wood. It's a wonder someone's not commented on the inner resenance of the wood causing ground noise, or some such bull****. Anyway, after all the pro's and con's , in's and out's, chicken's and egg's , asking as a consumer of this sort of stuff, Just what does it sound like, and is it any good. Iv'e found that simply because it looks the part, does not mean it will deliver, I had a mate come up the other weekend with a lambo Countach, dunno where he got it, but hopyfully he took the thing back, load of rubbish, and when you consider the price , when it was new. So looks mean nothing, performance is what counts. I also could not find any info on what the output or your amp was, but then I wasn't really looking. And regardless of what you might have used or not used, the bottom line is the results it can produce, completely regardless of measurements, data, or other total rubbish, that might look very respectable on paper, but does absolutely nothing to the end product, which is the sound it produces. You say that you tested it , and had the volume turned up, so you could no longer stay in the room, but failed to say for how long was it running, Was it 10 minutes, a couple of hours, a day, a week, or until the thing self-destructed. So as you could then work out what had failed and replaced it with something bigger and stronger.. You also failed to say how big the room was.. You may be surprised to learn, that some people do run there stuff at maximum volumes, to the point where crossover coils melt, and catch fire. Finally, your plugs are nothing special, I can get the same things from WES a lot cheaper then there quoting. bassett |
#71
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"Patrick Turner" wrote in message by e.mail are former I must be the exception. I have access to a bunch of little secret groups and won't take part in any of them. I have visted some of these groups but rarely felt a need to reply to anything I read, or I would have shown them more interest. But I only get to talk to maybe one or two people who often don't know very much and who hate their pet theories being challenged. I'd much rather post to the widest pssible audience. I would say that there are a large number of people in the minor groups who keep their eye on what is said here, but are afraid to take part because they would just get treated as fools or idiots. But because this is an unmoderated group, ie, is like a beach without a shark net, one has to be concise and truthful and knowledgeable to take a swim in these waters, and be quite prepared to proove what you say, and say a lot in explanation, not just some dumb one liner. So there is an imperative to bring one's technical competence up to a certain level BEFORE trying to discuss matters with authority, and unless you have studied and done your homework, ridicule greets you if you come here unprepared. All these little groups have HORRIBLE access paths and their site all don't work as easy and simply as a usernet group, with the groups listed in my inbox, and one click brings me to the day's postings with header titles, and I can review everything posted for the recent past. Another click brings me whatever post i want to reply to. one more click is for reply, and I get a full page to type into, not some STOOPID 100mm x 50mm section of the screen. My intelligence is insulted by the outright display of incompetence promulgated by all these little discussion groups; they'd like me there, I have been invited, but they want me to eat a **** sandwich before and while I take part. They know where I am, and where I post. Why can't they be real men and expose their ideas to the whole world without fear like I do? They don't like the heat of being challenged, they expect to get away with believeing their own BS, and most have no passion about anything. I am not going to waste my precious time yabbering at dumbos via rottenly set up group formats. I wouldn't mind being able to take part, but its all got to be easier to use. Patrick Turner. Well if I wasn't depressed before, I am now. Your the sort of person who would complain about the cab fare to the bridge, you were going to jump off. Mate, get a grip, go out and buy yourself a good root, you might just feel a bit better. If you where happy, you would complain about the cost of breathing, and the time it took out of your day. bassett |
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"west" wrote in message newsVgTh.5927$SK3.3050@trnddc03... "Iain Churches" wrote in message . fi... Andre asks what all the tubeheads are doing. You can see what this tubehead is doing at: http://www.kolumbus.fi/iain.churches/Preamp/203A.html It's a joint effort together with my pal Markus. He is a very skilled metal worker and made the casework, and also laser-cut the stainless steel top grille. We decided to do as much possible ourselves. Any comments would be of interest. Regards to all Iain Did Marcus and you do all the metal work in your lab or did he do any of it at his work place? If done at your lab, that leads me to another question ... Knowing little about metal work, can an individual buy all the needed equipment (perhaps you can list all the needed equipment) and diy or is this strictly left to the professional metal worker? I bet Marcus doesn't know Greek or Latin. ;-) Hi West. One of the big advantages of sharing a workshop with three other guys is that they all bring something to the party, in the shape of radial drill presses, a milling machine, a linisher, a fly press, a turret press punches, taps and dies etc. So then most work can be done in house. CNC machining, laser cutting and lettering is the exception. My pal is a highly skilled tool-maker, but just as you surmise he reads neither Greek nor Latin, neither can he play the Rachmaninoff piano concerto or transcribe a 5 part saxophone riff to manuscript paper:-)) I very much enjoy working with other people, hearing their ideas, and discussing with them. Each and everyone of us has a unique skill set, some are good at the visual concept, some can solder and wire to mil spec. Others make great coffee:-) If you are thinking of making chassiswork for hobby projects, perhaps it would be better, and time saving, to take your ideas and drawings to a third party metal-shop. If you can find a small place, a proto shop, with someone who is interested in what you are doing, then so much the better. You don't need incredibly small tolerances. These days, most metal shops use CNC machines and can drill punch and bend to 0.01mm with ease. The trouble is they need CAD generated files to make anything, and are not really interested in small quantities so a small old fashioned shop with a guillotine and a hydraulic folding press is what you are looking for:-) The other possibility is of course a pre fabricated chassis. Hammond have a good range, and the old ubiquitous battleship-grey has been augmented by a very smart black powder coated range. They also have tube cages to match. You can see the 1441 series and the 1454 cages at: http://www.hammondmfg.com/scpgMET.htm I have also been looking into the possibility of making PCBs, I currently use turret boards. Believe it or not, it is a lot cheaper to buy copper clad board, and have a PCB shop etch the copper away for you than buy plain board. But there are advantages in being able to design a ground plane on the reverse side of the board. Reading the replies to my question on this subject of PCBs here on RAT, one would get the impression that it was a waste of time even to try to get professional results. I had e-mails from several people, who described in detail their methods. One even sent some excellent pics of his work, on 2.4mm board, lacquered and silk screened. Another fellow who lives on the other side of the world, has offered to help me get started. People are generally pretty decent. Regards Iain |
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"bassett" wrote in message ... Well I,ve read all the posts about your little project, Hardly "little". I wouldn't like to estimate the number of man hours from first concepts to completion. It has been about two years, although we did have a prototype running about a yeara ago then someone bought it. And it does look the part, At least you have used proper wood, and not MDF with plastic veneer. tell me it's proper wood. Yes - solid teak. 25mm. People have also asked about walnut or Scandinavian pine. It's a wonder someone's not commented on the inner resenance of the wood causing ground noise, or some such bull****. There is still time:-) Anyway, after all the pro's and con's , in's and out's, chicken's and egg's , asking as a consumer of this sort of stuff, Just what does it sound like, and is it any good. About fifty people have hard it up to now. Many of these are audio pros. No-one could find anything negative to say about the sound. There have been a couple of comments about styling, but that's a personal thing anyway, and you can't hope to please everyone:-) Iv'e found that simply because it looks the part, does not mean it will deliver, I had a mate come up the other weekend with a lambo Countach, dunno where he got it, but hopefully he took the thing back, load of rubbish, and when you consider the price , when it was new. So looks mean nothing, performance is what counts. Indeed. I also could not find any info on what the output or your amp was, but then I wasn't really looking. It's a unity gain preamplifier. And regardless of what you might have used or not used, the bottom line is the results it can produce, completely regardless of measurements, data, or other total rubbish, that might look very respectable on paper, but does absolutely nothing to the end product, which is the sound it produces. Personally I agree with Morgan Jones who writes that no preamplifier is better than any preamplifier, so at home I have my CD player plugged straight into my power amp (sensitivity 0dBV for 50W) with a pair of stepped attenuators at the front end. But when you have more than one source, even though you may not need extra gain, some sort of a preamp with multiple inputs is required. You say that you tested it , and had the volume turned up, so you could no longer stay in the room, but failed to say for how long was it running, Was it 10 minutes, a couple of hours, a day, a week, or until the thing self-destructed. So as you could then work out what had failed and replaced it with something bigger and stronger.. You also failed to say how big the room was.. We were discussing the noise floor. I mentioned that I turned the system to a level at which one could not stay in the room. Then, using the remote, I put the CD player onto pause, and went back to the listening position to evaluate the system noise. There was none. This was not a test of durability. The build quality of this amp and the quality of components used make me think that it will be totally reliable Time will tell. Many have reservations about lead-free solder! The tubes are running at fairly low current, with regulated current for heater and regulated voltage for HT. They should run for 10 000 hrs before needing to be replaced. Finally, your plugs are nothing special, I can get the same things from WES a lot cheaper then there quoting. I did not claim they were anything special. They are the industry standard studio and broadcast unbalanced analogue connector. Best regards Iain |
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"John Byrns" wrote in message ... Speaking of perfection, did you ever consider building a matching equalizer to go with the preamp? Regards, John Byrns Gosh, John. You must have a crystal ball:-) But first comes the matching RIAA stage, a grounded grid cascode which will run from the same psu. Then I thought about an equaliser, a subtle three-band -3dB, 0, +3dB at LF MF and HF. Plus of course an ME (eye tube) to indicate level:-)) Iain |
#75
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"John Byrns" wrote in message ... In article , "Iain Churches" wrote: "John Byrns" wrote in message ... In article , "Iain Churches" wrote: No mystery Patrick. I stated clearly that it is an active load cathode follower, which was chosen after comparison with a mu-follower and a cascode. I have no schematic drawn. It can be found in any one of a dozen books The cathode follower part sounds straight forward enough, but the "active load" part could be anyone of a number of things. Is the circuit what I think is called a "White" cathode follower? The White CF is similar, except that the anode of the bottom triode and the cathode of the upper triode are usually at the same potential. The grid of the top triode is biased by a pair of resistors from the B+ to ground, with the junction of these two Rs connected to the grid. On the ALCF the grid of the lower tube is biased in this way. The anode of the lower tube and the cathode of the upper tube are separated by a resistor of about 1k2 to give a differential of about 2V between them. 1M is then connected from anode 1 to grid 2 for bias (rather like the mu-follower) OK, Thanks, I think I understand. The bias sounds like it is done the same way as the circuit at the link I posted. It is not clear from your description if the bottom triode serves simply as a passive load for the cathode follower, or if a signal is applied to the grid of the lower triode making it an active load? Just as in the White topology, the input to the ALCF is taken to the grid of the upper tube. The lower triode is a CCS. Iain |
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Hello John, Just a brief "top" reply to your post. Thanks very much for your comments - greatly appreciated. I am off on a recording trip tomorrow. I wil print out your post, and take it with me for careful reading. As I mentioned in my earlier post, there is no audible noise from the listening position, so I think that the performance of the amplifier is as it should be, but my measuring technique leaves something to be desired:-) Many thanks again for your input. Best regards Iain "John Byrns" wrote in message ... Hi Iain, There are two issues here, first what sort of unweighted SNR you should expect, and second what effect will A weighting have on the SNR. Taking the A weighting issue first, I would think the effect would depend on what the dominant noise source is in your preamp, is it noise due to random processes in the components used, or is it due to line frequency harmonics from the power supply? How was the input terminated for the SNR measurements? With respect to the noise you should expect, assuming all the line frequency related noise has been dealt with, we should be able to calculate that. Unfortunately I don't do those calculations on a daily basis, so I would have to root around in my files to find the relevant formulas. Perhaps while I am searching, someone else has the necessary formulas right at their finger tips, and can provide the answer more quickly than I ccould? When Phil said your output noise level was too high I started wondering could he be correct? My first thought was my "Power Amplifier Without Power Transformer", which uses a 12SN7 driver stage. This amplifier has an output noise level greater than 80 dB below 1 Watt output, without negative feedback. I thought I would do a quick calculation to estimate what the noise level at the output of the 12SN7 stage might be. I did the calculations with a calculator, and without writing anything down, and found the noise level at the output of of the 12SN7 to be in the same general ballpark as your preamp. This did not seem to be a promising result relative to your preamp, as my PAWPT uses a series heater string across the power line, and a half-wave rectifier directly off the power line, with the output stage B supply filtered only by the main filter capacitor, not necessarily a recipe for low noise. I will have to run through the calculations again, writing down the steps, to be sure I didn't skip a digit somewhere. Another way to look at the preamp output noise is to consider what would happen if you feed a 120 uV noise source into a power amp with a typical gain of 20X. For an 8 Ohm load that would give an output noise level only about 61 dB below 1 Watt, not exactly a top rank result. Only the actual calculation, which I will try to do later, will tell us what sort of noise level you should expect. I would hope for 40 uV of noise at worst, and would prefer less than 12 uV of noise, although I don't know if that is possible. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
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"Patrick Turner" wrote in message ... To measure noise below 300uV, you need a low noise amplifier to raise its level to work a meter or display it on a CRO or both. So you need to make a wide band amp, at least 10Hz to 20kHz with gain of up to 1,000 for noise measurements, but gain able to be varied between say 10 and 1,000. So if noise = 3uV, it is amplified to 3mV after the amp, and able to be measured/displayed by gear you have already. Ok. Understood. Thanks for that. I have a good selection of op-amps used in prof recording consoles. I can get something put together without too much trouble. A "lurker" on RAT sent me an e-mail with the same info as you supplied, and offered to make such a measurement amp, so that is also an option. Its so darn easy, but takes time and understanding, and you are short of both. For me this is a hobby. I devote as much time to it as I am able. Don't be too pretentious about "understanding" You are a professional amp builder, one would expect you to know the detail. My skillset and training is totally different. I am currently editing a 24 track big band recording from a full score. Would you know where to start, Patrick? :-) The remainder of your post contains much interesting info. Thanks. I have printed it out for careful study. Best regards Iain |
#78
Posted to rec.audio.tubes
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Recently completed project
"Patrick Turner" wrote in message ... Iain Churches wrote: Tremaine 4th edition dates from 1975. No mystery Patrick. I stated clearly that it is an active load cathode follower, which was chosen after comparison with a mu-follower and a cascode. I have no schematic drawn. It can be found in any one of a dozen books Hardly any of us have a copy of Tremaine's 4th Edition, Audio Encyclopedia. That's probably because its name is Audio Cyclopedia:-)) There IS a MYSTERY. How can we talk about your amp details without a schematic???????? It will be just bull****ting into the wind without one. You may indeed have a nice device, but here you have to proove it. No Patrick. I don't have to *proove* (sic) anything to anyone, here. This is not the Spanish Inquisition. Neither is it a professional group (if it were, you would be the sole member:-) As I understand it, RAT is a recreational (hobby) group. Against the wished of my pal with whom I shared this project, I started this thread on RAT to relieve the monotony of Arny's OT drivel and Phil's cut-and-paste invective. Here is where when someone says something, it better be right, and reasons given, or its deemed to be wrong. When you show something, its prudent to offer the full story with a schematic. Few hobbyists can meet your expectations. That is probably why so few project threads appear. If you set the threshold too high you will end up with a pleasant but fast-shrinking band of tubeheads, plus one autistic Australian toaster repairer, and a Born Again tambourine basher from Michigan:-) Iain |
#79
Posted to rec.audio.tubes
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Recently completed project
Iain Churches wrote: "Patrick Turner" wrote in message ... I must be the exception. I have access to a bunch of little secret groups and won't take part in any of them. I think you are mistaken Patrick.The groups to which you refer are moderated but not closed groups. That's a totally different thing altogether. OK, you make a further important distinction. The "little" groups I refer to are the ones the public is free to read, but you have to subscribe, use a pass word, and obey rules or get banned. I have nothing against all these things, its just that I find most of the groups are clumsy to use and read and there simply isn't enough content for me to become involved with. Closed groups, for example the broadcast and recording group to which I have access, are used by professionals. If they are not members of the university, institute or company which runs the group, they are there strictly by invitation only. They wouldn't like me being around then. Your are correct in saying that people do keep an eye on RAT. Recruiting to closed groups is not uncommon, and I have never met anyone who has refused the invitation:-) I recall I have subscribed to a few, been accepted, made one post, and never returned. I read a dozen posts later and not feel I could say much that wasn't already being said about the trivial / beginner issue being discussed. If they had any questions, they know where I am. Some weeks I get several private queries from around the world, and some guys are building things and need the help, and deserve it, because rather than just sit typing BS, they are soldering and measuring and calculating their way through a project. You bump into lot of familiar and respected names. Have you ever wondered why, with the exception of yourself, no other professional audio designer or manufacturer has a presence here? Because they are thin skinned, and when skinned alive here they die fast after shrivelling up. Their high profile name rests on a delicate ego. They are very choosy about who they sit next to in the railway carriage of discussions, and as you know, r.a.t is a bit like a Bombay train full of noisy smelly workers going home for the day after sundown. If they don't like Hindu morons, they better keep quiet. If they can afford it, they go in the 1st Class carriage, and talk about the weather, politics, and the economy. There is no kudos to be gained when talking to the masses, unless you want them to vote for you, and then you tell them what they want to hear, even in the 1st class carriage. If you start asking questions, making criticisms, they might throw you off the train. Many "well respected" ppl's ideas can certainly be challenged, questioned, ridiculed, parodied, and their elete status can be reduced to being fairly ordinary. Here there are NO SACRED COWS!! Everything and anything is fair game for comment. If someone survives here, they are fit, agile, and durable indeed, and truly one who belongs to all manner of people, at home in a pub, or in court of a king. I once tried rec.audio.hi-end, and found it had the the most stultifying atmosphere. To be someone of influence there I should have become far wealthier from audio, after starting 40 years ago. I felt I was very much a johnny come lately there. And they didn't like tube gear much, let alone boutique DIY. So after a few weeks I found I just didn't enjoy r.a.h-e My ego fell off the back of a truck 20 years ago, and being from a building worker background, I got use to spending all day working hard down some hell hole with mud up to my knees, until the job is done. When confronted with unruly people around me I wasted no time dealing with them. I don't have to be too rugged too long, and they get the drift. I don't have a "high profile" worth keeping mud free. I'm just a bloke who enjoys audio and making gear and I have some ideas about it worth sharing. So I have written a website to make sure everyone knows what i know if they want to read something. So I save having to repeat what is mainly common sense. If people follow my reasoning, they will find good music. When I was about 25, I was working as a sub-foreman on a large multi-storey building at NSW University. I'd begun there after being drawn from ranks of my peers as being worth being trained for such large complex works. I had a tendency to waffle on, and not compose language properly. A seriously no-nonsense project general foreman once told me "Look here mate, say only what you mean, and mean what you say, OK!" The othe boss in charge was the project manager, and once had me run to the 17th floor with messages for people or to find something, or find out about something 4 times before morning tea one day. I just tried to obey, and he must have been impressed, because I was quick and efficient, and showed no strain. But he told me plainly, "Spit it out man!, which do you mean? don't speak to me in riddles!", after I'd given a contradictory answer to his questions. In the trades, there can only be one answer. I was somewhat overwhelmed at first by the size of the job, and could easily be distracted, and it took me a month to stop bull****ting, and make each word count especially when addressing my superiors, so I had to start each day commanding myself to be a Better Builder Today!, OK. I needed to ask more questions, and observe more thouroughly. I became a better builder indeed, and years later I could thank the hardened task masters for their NO BS approach to all they did. When others were sacked, I was retained. Apprentices sent to me for training didn't have a picnic either, they actually had to work, and sometimes motivation meant some very heated discussions with a deal of acrimony about the sloppy, untidy, un-timely, incompetent efforts they presented while they still expected to be paid the same wages. Luckily this didn't happen often, and I had a good reputation for running peaceful productive sites with a low panic level and good safety record. I could see trouble coming, and didn't provoke it. One foreman the company had who'd been an Olympic rower in '56 and who was the most rugged and powerful person once hung an apprentice over a balcony of a 14 storey building by holding onto only one ankle to impress upon the lad that misbehaviour was not going to occur again, and if it did, another session over the balcony would occur, only he would let go. "Big Dennis" as we called him was otherwise a very fine foreman we all liked. I don't plan to enforce learning here like Dennis tried then. Too over-the-top! In other areas of my life, such as personal relationships, I've tried to have the same NO BS approach, and I've always preferred to back truth, even if it embarrassed mates, or a succession of females. I was damn honest, and although some office managers and shielas sometimes didn't like it during disputes, they could respect it. When I come here, I naturally expect competent standards, and will try to help anyone get there who isn't there yet. Many in other groups are not very prolific, and just want to sit around and chat without any great goal in mind, and that's all fine, but I like to see things achieved after a day's efforts. Patrick Turner Regards Iain |
#80
Posted to rec.audio.tubes
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Recently completed project
I am not going to waste my precious time yabbering at dumbos via rottenly set up group formats. I wouldn't mind being able to take part, but its all got to be easier to use. Patrick Turner. Well if I wasn't depressed before, I am now. Your the sort of person who would complain about the cab fare to the bridge, you were going to jump off. No, I'd drive myself; no whingeing. Mate, get a grip, go out and buy yourself a good root, you might just feel a bit better. If you where happy, you would complain about the cost of breathing, and the time it took out of your day. bassett Be a nice doggie Bassett, and do try to finish your bowl of Chum. Do not bassett hounds always look depressed? those long droopy ears, legs way to short to run with? I'd sure be depressed if I was a bassett. I'd smell a bitch in heat and not be able to run after her. When I got to her many hours later, mounting her would be impossible, because where I wanna go would be way UP there..... Patrick Turner. |
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