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#1
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833 Amp
Fellow Rodents,
Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west |
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#2
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The 833 is a Class B transmitting tube. The Gates/Harris BC-1 series
of broadcast transmitters uses two in push pull as a modulator-in other words, an amplifier with a special output transformer. Single ended you will need to run it with positive grid voltage which is a real mess. The Japanese guru who was behind WAVAC wrote a book and you can buy it and get it translated if you are sufficiently motivated, but, my advice is to recognize the laws of physics and leave the 833 alone unless you are a broadcaster or ham with a Gates transmitter. If you insist on building single ended amps use a low or medium mu tube needing enough bias voltage you can swing it far, far from ground. |
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#3
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west wrote: Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west I just tried to send you a schematic but maybe it won't make it because i can't recieve emails at the moment. It uses 6SN7 iput, 6V6 in triode for gain, 6V6 in triode as a cathode follower driver buffer. No interstage tranny is needed. Patrick Turner. |
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#4
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#5
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"west" wrote in message
news  Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west WAVAC just came out with the SH-833 mono blocks that put out 150Watts. The SH-833 works in class A (I believe) with a KT-88 in triode mode for the driver. Old time reviewers typically say "This amp can easily drive anything and is the best sounding amp I ever heard, hands down. Incidentally, if you want a SH-833, all you have to shell out is a cool $350,000. Chump change for Fabio. west |
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#6
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I still have all my "practical engineering" doubts about these "extreme"
units: I think that it's wiser to get the most out of a certain amount of money by placing it where it produces the maximum of positive effect. This means that the whole system, be it the amp or the whole HiFi chain should be checked for "weak points", and the economic effort should be devolved to "debottlenecking". Ok, let's suppose that mr. Westley has got great LS, a very good (tubed) DAC, a mains filter (I just use a massive 220V to 220V isolation transformer), a good preamp and a terrific collection of CDs, but the amp is missing, he needs 100W and he's got so much $ he even considered the Wavac. What's the most sensible thing to do? First: take a 1st class air ticket to London/Berlin/St.Petersburg/Moscow/Milan/Paris and a 1st row ticket for all the local Philarmonics. Call in at the NY Philarmonic while coming back home. It still will cost much less than the Wavac Second best: get any good 200W PP amp and spend the rest to do the same as above but with economy class tickets. Jokes apart: A - a SE amp using an 833 poses an ENORMOUS load on the OPT (1500+V and LOTS of DC), which means that it is very difficult and expensive to make a GOOD OPT. "Difficult" does not mean "impossible" (this is for Mr. Patrick, I know You can do it..) but a similarly sounding one, if made for (say) 6x 6550s in PPP, would cost (and weigh in) @ about 1/3. B - the driver circuit for a more "viable" output tube can be much simpler and at the good end BETTER (no need for positive grid or huge voltage swing) C - a 500V power supply can even be regulated (if You're a maniac), a 1500V one... well, see above, nothing's impossible, but... D - the 833 tube itself is radio stuff: it was not meant to be linear, and I doubt that it will sound good at 100W out without a substantial amount of feedback. This in turn means that the "subtle nuances" that many "golden ears" claim to hear through SE amps are lost: SE "magic", if any, is related to INTRINSIC linearity: zero feedback, all triodes and two/three components MAXIMUM from CD to LS. My beloved 2A3 is like this, but it only delivers 3-dot-something watts. Briefly: I still think that something like the venerable Harman-Kardon Citation IV (not to quote OZ ones..) is a wiser (cost-effective) way to Audio Heaven. Anyway, if You want to make a real beast, Patrick's project is a good starting point. For the gain stages I'd consider using one of the (many) triodes/pentodes like 6BM8, 6GV8 etc. : cheap as dirt and easy to get. BTW: I'm finishing my first 100W mono-block, using SV811-10 in PP. Unfortunately this tube is as extinct as a dodo now. Ciao Fabio "west" ha scritto nel messaggio om... "west" wrote in message news Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west WAVAC just came out with the SH-833 mono blocks that put out 150Watts. The SH-833 works in class A (I believe) with a KT-88 in triode mode for the driver. Old time reviewers typically say "This amp can easily drive anything and is the best sounding amp I ever heard, hands down. Incidentally, if you want a SH-833, all you have to shell out is a cool $350,000. 300,000 Euros? If I could live for 10 years without even drink a glass of water, I could put'em together.... Chump change for Fabio. west |
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#7
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west wrote:
Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west There are dreamers & there are doers. How about giving us a summary of the amplifiers you have successfully built sofar, so that we can decide if all the advice of the past few months is going somewhere! Good Luck, John Stewart |
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#9
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"John Stewart" wrote in message
... west wrote: Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west There are dreamers & there are doers. How about giving us a summary of the amplifiers you have successfully built sofar, so that we can decide if all the advice of the past few months is going somewhere! Good Luck, John Stewart You first Johnny. west |
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#11
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I guess this is a prime example about RAT going down the toilet, as so many
complained. We were all discussing and many learning about the pros & cons of an 833 amp and someone got insecure about their manhood size. I bet that shoots the crap out of this thread. I doubt if anyone else will post anymore info on this subject. May those who were guilty of diverting the subject to personal prowess and those who encouraged the perpetrator wallow in their own stench. I'm gone. west "Jon Yaeger" wrote in message ... in article , west at wrote on 7/1/05 12:01 PM: "John Stewart" wrote in message ... west wrote: Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west There are dreamers & there are doers. How about giving us a summary of the amplifiers you have successfully built sofar, so that we can decide if all the advice of the past few months is going somewhere! Good Luck, John Stewart You first Johnny. west I don't know you or your work West, but I'd guess that John's got you beat by a factor of 5:1. He's built a heck of a lot of (working) designs . . . .. . |
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#12
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I just felt that the 833 probably wasn't a highly suitable type for
the application. There is no question they can be made to work. Whether the finished product will perform well is open to question. Apparently the WAVAC amp has abysmal measured performance, which means that if it sounds good your ears are what is needing further testing, or in your environment you didn't need a lot of amp to begin with. |
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#13
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wrote in message
oups.com... I just felt that the 833 probably wasn't a highly suitable type for the application. There is no question they can be made to work. Whether the finished product will perform well is open to question. Apparently the WAVAC amp has abysmal measured performance, which means that if it sounds good your ears are what is needing further testing, or in your environment you didn't need a lot of amp to begin with. I thought you post was well written & informative. I just wondered how the Japanese did it. WE437A input tube. A triode fitted KT-88 as a driver tube and of course the 833 as a configuration with all the low level subtle resolution of an SET in class A, pushing an amazing 150W. Now don't you think that's at least interesting? If we knew something about their techniques, I think we could all benefit. I never said that I wanted to build such an amp, just wanted to know how it was done. There was absolutely nothing wrong with any of the posts until John Steward once again asked me to prove my worth to be on this Newsgroup. I don't know exactly what his problem is besides his own insecurity. I asked him to show us what has he done LATELY. My question is always met with silence. This tread started off interesting until he poisoned the well and killed the flow of thought. One need to look no further to see one of the culprits who is responsible for RAT's present condition. west |
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#14
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west wrote: wrote in message oups.com... I just felt that the 833 probably wasn't a highly suitable type for the application. There is no question they can be made to work. Whether the finished product will perform well is open to question. Apparently the WAVAC amp has abysmal measured performance, which means that if it sounds good your ears are what is needing further testing, or in your environment you didn't need a lot of amp to begin with. I thought you post was well written & informative. I just wondered how the Japanese did it. WE437A input tube. A triode fitted KT-88 as a driver tube and of course the 833 as a configuration with all the low level subtle resolution of an SET in class A, pushing an amazing 150W. Nobu Shishido, apparently a children's author by trade, wrote a book shortly before he died on building single-ended (and apparently push-pull as well) Class A amplifiers using inexpensive transmitting tubes designed for zero bias grounded grid Class B or C RF service. I don't have handy any curves on the 833 and I have no idea what its biasing requirements are, but most tubes like this are designed to run at well under rated dissipation with design B+ at zero grid voltage. The 3-500Z is the most common "modern" (ahem) glass transmititng triode in this category. EIFL sells this book, I believe. Many are in the country as are many other Japanese tube audio books, because many tube DIY gurus such as Bender and Gizmo Rosenberg promoted buying them and they were very chi-chi to have. I haven't heard the WAVAC 833 amp....and truthfully have little desire to. I have heard many single ended tube amps using 300B's, 45s, 50s, 2A3s, 211s, 845s, and about every other such tube (plus triode-strapped and other configs of regular beam power audio tubes) and in every case have come to the overall conclusion that while in some cases the sound is admittedly better than the numbers suggest, when you get into music that really does demand more than that so-called magical first watt or two (which usually isn't anyway) with grand crescendo and percussivenes in the lower registers, it falls apart. That said I'm open to the possibility that single ended amps can do good things in actively crossed-over treble and occasionally midrange installations, with output transformers specifically developed for performance in those bandwidths and deliberately not handling the bass frequencies. No one is commercially producing such amps, or transformers. |
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#15
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IMHO a SE amp will deliver SE "magic" if:
- it is all made with highly linear AUDIO triodes, say 6SN7, 2A3, etc. - distortion is INTRINSICALLY low - it uses absolutely zero feedback unless strictly local (CF allowed) - time/phase coherence is preserved, LS EMF is not reflected back to input stage - it does not require huge DC - smaller output iron, with many interleaves and strict input/output coupling - it does not need 200V or more of driving voltage (distortion in Class A triode is directrly proportional to voltage swing) - it does not need 2000V B+ - feed does not need to use series capacitors having worse resistance. Using a SE to deliver 100+W is a bit like using a Ferrari to transport concrete beams. It is not impossible, but a truck would do it better. The Wavac scheme is plain and straightforward, using a "robust" tube like the KT88 to drive the 833 somewhere into the positive grid zone. Patrick's scheme (and the like, the GEC scheme) is better 'cause it foresees a cathode coupled drive; the 833 is a radio triode and it sucks POWER thru its grid, in order to deliver it - amplified - to the load. A RC - coupled KT88, connected from the anode side, does not provide an impedance low enough to drive that monster to FULL swing. Nevertheless, if I needed 100+W, I'd go for a six/eightpack of UL KT88s in PP, with the minimum amount of feedback required. Don't use a .44M to kill a mosquito. Ciao Fabio ha scritto nel messaggio ups.com... west wrote: wrote in message oups.com... I just felt that the 833 probably wasn't a highly suitable type for the application. There is no question they can be made to work. Whether the finished product will perform well is open to question. Apparently the WAVAC amp has abysmal measured performance, which means that if it sounds good your ears are what is needing further testing, or in your environment you didn't need a lot of amp to begin with. I thought you post was well written & informative. I just wondered how the Japanese did it. WE437A input tube. A triode fitted KT-88 as a driver tube and of course the 833 as a configuration with all the low level subtle resolution of an SET in class A, pushing an amazing 150W. Nobu Shishido, apparently a children's author by trade, wrote a book shortly before he died on building single-ended (and apparently push-pull as well) Class A amplifiers using inexpensive transmitting tubes designed for zero bias grounded grid Class B or C RF service. I don't have handy any curves on the 833 and I have no idea what its biasing requirements are, but most tubes like this are designed to run at well under rated dissipation with design B+ at zero grid voltage. The 3-500Z is the most common "modern" (ahem) glass transmititng triode in this category. EIFL sells this book, I believe. Many are in the country as are many other Japanese tube audio books, because many tube DIY gurus such as Bender and Gizmo Rosenberg promoted buying them and they were very chi-chi to have. I haven't heard the WAVAC 833 amp....and truthfully have little desire to. I have heard many single ended tube amps using 300B's, 45s, 50s, 2A3s, 211s, 845s, and about every other such tube (plus triode-strapped and other configs of regular beam power audio tubes) and in every case have come to the overall conclusion that while in some cases the sound is admittedly better than the numbers suggest, when you get into music that really does demand more than that so-called magical first watt or two (which usually isn't anyway) with grand crescendo and percussivenes in the lower registers, it falls apart. That said I'm open to the possibility that single ended amps can do good things in actively crossed-over treble and occasionally midrange installations, with output transformers specifically developed for performance in those bandwidths and deliberately not handling the bass frequencies. No one is commercially producing such amps, or transformers. |
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#16
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west wrote:
wrote in message oups.com... I just felt that the 833 probably wasn't a highly suitable type for the application. There is no question they can be made to work. Whether the finished product will perform well is open to question. Apparently the WAVAC amp has abysmal measured performance, which means that if it sounds good your ears are what is needing further testing, or in your environment you didn't need a lot of amp to begin with. I thought you post was well written & informative. I just wondered how the Japanese did it. WE437A input tube. A triode fitted KT-88 as a driver tube and of course the 833 as a configuration with all the low level subtle resolution of an SET in class A, pushing an amazing 150W. Now don't you think that's at least interesting? If we knew something about their techniques, I think we could all benefit. I never said that I wanted to build such an amp, just wanted to know how it was done. There was absolutely nothing wrong with any of the posts until John Steward once again asked me to prove my worth to be on this Newsgroup. I don't know exactly what his problem is besides his own insecurity. I asked him to show us what has he done LATELY. My question is always met with silence. This tread started off interesting until he poisoned the well and killed the flow of thought. One need to look no further to see one of the culprits who is responsible for RAT's present condition. west Settle down now Westley. My post was not meant to embarrass you but rather as a wakeup call. You have received quite a bit of advice here on the NG from several of us & I believe it is time for you to show us that our efforts can produce results. Perhaps I've missed something but I have yet to see any evidence that you have made any effort to build a vacuum tube amp. If I am mistaken then please let me know what you have accomplished. A schematic would be nice so we can make helpful comments. And I certainly have no objections at all about you being here on the NG. But rather than your leaping from topic to topic, I for one would like to see some results. If you would like to sample my work all you need to do is look it up in past copies of Glass Audio, AudioXpress & Electronics World. The most recent was a major article on Norman Crowhurst's Twin Coupled Amplifier from the late 50's. You will find it in the August 2004 Issue of AudioXpress magazine. Another article will be published sometime later this year. Am I insecure? Not too damned likely! Cheers, John Stewart |
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#17
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In every instance when I hear a hi-fi unit that is pronounced "truly
magical" or some other nance sounding apellation, it actually is very colored and alters the sound somehow or other. The really good stuff allows bad recordings to sound bad and mediocre ones to stay that way too. All the best sounding power amplifiers use some feedback somewhere and usually measure reasonably well, but not as good as say modern McIntosh. A reasonable damping factor is necessary, but not an extremely high one, and I think variable damping was a good thing with a lot of speakers. Once you hit a passive crossover, of course, all bets are off! |
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#18
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"Johnny Boy, I had my own biomedical and Nuclear research business which came out with many innovative circuits and retrofits. I have a patent pending for one of them at this time. The sale of my business has allowed me to semi-retire at a relatively young age. I have nothing to prove, especially to a self appointed idiot like you. Audio is new to me although I have installed audio and FM radio broadcast systems in a couple of churches as a donation. I have an extra class ham ticket and a commercial FCC license. I've built your run of the mill P/P UL amps and a few preamps that sound fine, nothing special, nothing challenging. I asked you not to post to my threads because I believe all you're doing is trying to flame. Why? I'm not that sure, presently. I have nothing to prove to anyone and would be happy to discuss my work with anyone who has a genuine interest. You know when sometimes your overheated and can feel the sweat running down your body? Well, not even a rivulet of perspiration running down one of my boys, will I give you. I'm sure you can transpose using the street vernacular. So Johnny Boy, you self appointed Narcissist, please keep your thoughts to yourself. They are irrelevant to the topic and are meant to humiliate.This will make twice you tried to break up this otherwise interesting thread. You have done the same in the past to me. What would you call someone who does this? I asked you politely in a private email so dirty laundry wouldn't be aired on this NG and you still choose to inflame regardless. We are all were waiting for what have you done recently. Perhaps you were good at one time but because of reasons unknown to us at this time, you're simply a has-been. Show us WITH THE DATES "what have you done for me LATELY? Can you take your own medicine? west. ----- Original Message ----- From: "John Stewart" Newsgroups: rec.audio.tubes Sent: Saturday, July 02, 2005 10:00 AM Subject: 833 Amp west wrote: wrote in message oups.com... I just felt that the 833 probably wasn't a highly suitable type for the application. There is no question they can be made to work. Whether the finished product will perform well is open to question. Apparently the WAVAC amp has abysmal measured performance, which means that if it sounds good your ears are what is needing further testing, or in your environment you didn't need a lot of amp to begin with. I thought you post was well written & informative. I just wondered how the Japanese did it. WE437A input tube. A triode fitted KT-88 as a driver tube and of course the 833 as a configuration with all the low level subtle resolution of an SET in class A, pushing an amazing 150W. Now don't you think that's at least interesting? If we knew something about their techniques, I think we could all benefit. I never said that I wanted to build such an amp, just wanted to know how it was done. There was absolutely nothing wrong with any of the posts until John Steward once again asked me to prove my worth to be on this Newsgroup. I don't know exactly what his problem is besides his own insecurity. I asked him to show us what has he done LATELY. My question is always met with silence. This tread started off interesting until he poisoned the well and killed the flow of thought. One need to look no further to see one of the culprits who is responsible for RAT's present condition. west Settle down now Westley. My post was not meant to embarrass you but rather as a wakeup call. You have received quite a bit of advice here on the NG from several of us & I believe it is time for you to show us that our efforts can produce results. Perhaps I've missed something but I have yet to see any evidence that you have made any effort to build a vacuum tube amp. If I am mistaken then please let me know what you have accomplished. A schematic would be nice so we can make helpful comments. And I certainly have no objections at all about you being here on the NG. But rather than your leaping from topic to topic, I for one would like to see some results. If you would like to sample my work all you need to do is look it up in past copies of Glass Audio, AudioXpress & Electronics World. The most recent was a major article on Norman Crowhurst's Twin Coupled Amplifier from the late 50's. You will find it in the August 2004 Issue of AudioXpress magazine Settle down now Westley. My post was not meant to embarrass you but rather as a wakeup call. You have received quite a bit of advice here on the NG from several of us & I believe it is time for you to show us that our efforts can produce results. Perhaps I've missed something but I have yet to see any evidence that you have made any effort to build a vacuum tube amp. If I am mistaken then please let me know what you have accomplished. A schematic would be nice so we can make helpful comments. And I certainly have no objections at all about you being here on the NG. But rather than your leaping from topic to topic, I for one would like to see some results. If you would like to sample my work all you need to do is look it up in past copies of Glass Audio, AudioXpress & Electronics World. The most recent was a major article on Norman Crowhurst's Twin Coupled Amplifier from the late 50's. You will find it in the August 2004 Issue of AudioXpress magazine. Another article will be published sometime later this year. Am I insecure? Not too damned likely! Cheers, John Stewart |
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#19
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"west" wrote: I guess this is a prime example about RAT going down the toilet, as so many complained. But they were wrong, every last pathetic whinging arse-licking useless one of them. Otherwise you wouldn't have come begging here. Can you think of any reason anyone would want to continue wasting words on you? Only those who like having their arses licked, I observe. I'm gone. Good. er...except you haven't gone...perhaps just a last snivel on your way out? cheers Ian |
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#20
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wrote in message ups.com... In every instance when I hear a hi-fi unit that is pronounced "truly magical" or some other nance sounding apellation, it actually is very colored and alters the sound somehow or other. The really good stuff allows bad recordings to sound bad and mediocre ones to stay that way too. All the best sounding power amplifiers use some feedback somewhere and usually measure reasonably well, but not as good as say modern McIntosh. A reasonable damping factor is necessary, but not an extremely high one, and I think variable damping was a good thing with a lot of speakers. Once you hit a passive crossover, of course, all bets are off! Can't argue with those thoughts. Subjective sales fluff always turns me off. It's ironic that WAVAC publishes and explains their specs and methodology but with a glaring omission. That's feedback. I imagine that the amp has some merits and perhaps an innovative circuit. One thing for sure is the obstacle of the OPT. It must be something to behold. I wonder if such an amp without all the exotic materials is in the realm and feasibility of some of the more accomplished RATS. I know it's only something I can dream of. Do you think it can be home made? What would be some of the major obstacles? Also which MAC do you like? west BTW: what's your handle? |
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#21
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west wrote:
"Johnny Boy, I had my own biomedical and Nuclear research business which came out wi= th many innovative circuits and retrofits. I have a patent pending for one= of them at this time. The sale of my business has allowed me to semi-retir= e at a relatively young age. I have nothing to prove, especially to a self appointed idiot like you. Audio is new to me although I have installed = audio and FM radio broadcast systems in a couple of churches as a donation. I= have an extra class ham ticket and a commercial FCC license. I've built your= run of the mill P/P UL amps and a few preamps that sound fine, nothing spec= ial, nothing challenging. I asked you not to post to my threads because I be= lieve all you're doing is trying to flame. Why? I'm not that sure, presently.= I have nothing to prove to anyone and would be happy to discuss my work w= ith anyone who has a genuine interest. You know when sometimes your overheated and can feel the sweat running= down your body? Well, not even a rivulet of perspiration running down one of= my boys, will I give you. I'm sure you can transpose using the street vernacular. So Johnny Boy, you self appointed Narcissist, please keep y= our thoughts to yourself. They are irrelevant to the topic and are meant to= humiliate.This will make twice you tried to break up this otherwise interesting thread. You have done the same in the past to me. What woul= d you call someone who does this? I asked you politely in a private email so = dirty laundry wouldn't be aired on this NG and you still choose to inflame regardless. We are all were waiting for what have you done recently. Pe= rhaps you were good at one time but because of reasons unknown to us at this = time, you're simply a has-been. Show us WITH THE DATES "what have you done fo= r me LATELY? Can you take your own medicine? west. Thankyou for your carefully considered response. I was trying to make pea= ce here. Anyway, a list of articles I've authored & their publication dates are he= re. Not sure why you are asking for them now since they were sent to you in one o= f the private notes I sent you with other technical information you had asked f= or. I hope this is what you are looking for. Cheers, John Stewart Sunday, 15 May 2005 PUBLISHED IN AudioXpress Magazine AX Aug/04 p12 Norman Crowhurst's Twin Coupled Amp & Beyond AX Nov/03 p30 Amplifier Burst Testing AX May/02 p34 THE CIRCLOTRON AX Jul/01 p87 RESPONSE TO LETTER OF EG PETTIS AX Jul/01 p52 THE CONSTANT CURRENT REGULATOR AX Jun/01 p34 A DIFFERENT KIND OF LINE AMP AX Mar/01 p84 RESPONSE TO LETTER OF R M LEES AX Jan/01 p103 RESPONSE TO CIRCUIT OF CC WONG PUBLISHED IN GLASS AUDIO MAGAZINE GA 4/00 cover AN AFFORDABLE SE TRIODE AMP GA 4/00 p62 DIFFERENT TRIODE POWER AMP LETTER GA 2/00 p60 SE Circuit Fix GA 5/99 p68 DRIVING LESSONS LETTER (GEORGE DAVID) GA 5/99 p77 DELAY CIRCUIT MOD GA 3/99 p46 AN UPDATED TRIODE POWER AMP GA 2/99 p50 A DIFFERENT TRIODE POWER AMP GA 1/99 p67 BALANCING HEATERS GA 3/98 p12 Ripple Reduction in Full Wave CT Power Supplies GA 5/97 p61 SCHEMATIC CRITIQUE PUBLISHED IN GLASS AUDIO PROJECTS GAP p59 SAFE BIAS & BALANCE MEASUREMENT GAP p55 MORE POWER FOR THE AFFORDABLE SE AMP GAP p15 THE 33 POWER AMP PUBLISHED IN ELECTRONICS WORLD JUN 98 p476 REDUCING POWER SUPPLY MAINS FREQUENCY RIPPLE JUL 99 p570 TRIODE AUDIO AMPLIFIER WITH BOOTSTRAPPING COMING SOON TO AUDIOXPRESS MAGAZINE Norman Crowhurst's Twin Coupled Amp=85.Another Look JOHN STEWART file- Documents/Articles Published Rev C |
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#22
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"John Stewart" wrote in message ... west wrote: Thankyou for your carefully considered response. I was trying to make peace here. Anyway, a list of articles I've authored & their publication dates are here. Not sure why you are asking for them now since they were sent to you in one of the private notes I sent you with other technical information you had asked for. I hope this is what you are looking for. Cheers, John Stewart Sunday, 15 May 2005 PUBLISHED IN AudioXpress Magazine AX Aug/04 p12 Norman Crowhurst's Twin Coupled Amp & Beyond AX Nov/03 p30 Amplifier Burst Testing AX May/02 p34 THE CIRCLOTRON AX Jul/01 p87 RESPONSE TO LETTER OF EG PETTIS AX Jul/01 p52 THE CONSTANT CURRENT REGULATOR AX Jun/01 p34 A DIFFERENT KIND OF LINE AMP AX Mar/01 p84 RESPONSE TO LETTER OF R M LEES AX Jan/01 p103 RESPONSE TO CIRCUIT OF CC WONG PUBLISHED IN GLASS AUDIO MAGAZINE GA 4/00 cover AN AFFORDABLE SE TRIODE AMP GA 4/00 p62 DIFFERENT TRIODE POWER AMP LETTER GA 2/00 p60 SE Circuit Fix GA 5/99 p68 DRIVING LESSONS LETTER (GEORGE DAVID) GA 5/99 p77 DELAY CIRCUIT MOD GA 3/99 p46 AN UPDATED TRIODE POWER AMP GA 2/99 p50 A DIFFERENT TRIODE POWER AMP GA 1/99 p67 BALANCING HEATERS GA 3/98 p12 Ripple Reduction in Full Wave CT Power Supplies GA 5/97 p61 SCHEMATIC CRITIQUE PUBLISHED IN GLASS AUDIO PROJECTS GAP p59 SAFE BIAS & BALANCE MEASUREMENT GAP p55 MORE POWER FOR THE AFFORDABLE SE AMP GAP p15 THE 33 POWER AMP PUBLISHED IN ELECTRONICS WORLD JUN 98 p476 REDUCING POWER SUPPLY MAINS FREQUENCY RIPPLE JUL 99 p570 TRIODE AUDIO AMPLIFIER WITH BOOTSTRAPPING COMING SOON TO AUDIOXPRESS MAGAZINE Norman Crowhurst's Twin Coupled Amp..Another Look JOHN STEWART file- Documents/Articles Published Rev C You certainly know how to skirt a question. I ask you for the weather and you give me the baseball score. The question was the same one you posed to me. Show me the PROJECTS you have done recently. When was the last time you BUILT something (please give date). You can send an article from years ago to the next issue of a magazine. What have you done for me lately," as the Janet Jackson song says. west Do you see what I meant by flame? You throw out your garbage and the dogs come sniffing (Iverson) |
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west wrote:
...What have you done for me lately... ...the dogs come sniffing (Iverson) Iveson to you, ****. What have you *ever* done for *anybody*, parasite? You're all washed up here, slut. You're right, it's time to go. cheers, Ian |
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west wrote:
You certainly know how to skirt a question. I ask you for the weather and you give me the baseball score. The question was the same one you posed to me. Show me the PROJECTS you have done recently. When was the last time you BUILT something (please give date). You can send an article from years ago to the next issue of a magazine. What have you done for me lately," as the Janet Jackson song says. west Do you see what I meant by flame? You throw out your garbage and the dogs come sniffing (Iverson) The most recent project went to the publisher Audio Amateur Magazines on May 18th this year. The project was begun in mid-February of this year. It is a 15 watt amp running PP 6V6GT's in a circuit derived from the McIntosh. There are both fixed bias & cathode bias versions of the amp. Also, your choice of a regulated PS or a common CLC type, both using a SS rectifier. There are four tables of THD & individual harmonic distortion data along with plots of IMD. Many photos of sub-assemblies, all annotated, used in it's construction. There are eight schematics. I did the proofing of the article & sent it back to the publisher on June 15, 2005. All up there are about 45 pages. The text on their version is double spaced. It is a major work. I expect it to be published sometime later this year. Why don't you spend a buck & buy yourself some back copies of those magazines? They are very informative, with good articles by many authors on these subjects. See http://www.audioxpress.com Cheers, John Stewart |
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west wrote: wrote in message ups.com... In every instance when I hear a hi-fi unit that is pronounced "truly magical" or some other nance sounding apellation, it actually is very colored and alters the sound somehow or other. The really good stuff allows bad recordings to sound bad and mediocre ones to stay that way too. All the best sounding power amplifiers use some feedback somewhere and usually measure reasonably well, but not as good as say modern McIntosh. A reasonable damping factor is necessary, but not an extremely high one, and I think variable damping was a good thing with a lot of speakers. Once you hit a passive crossover, of course, all bets are off! Can't argue with those thoughts. Subjective sales fluff always turns me off. It's ironic that WAVAC publishes and explains their specs and methodology but with a glaring omission. That's feedback. Do you mean that WAVAC should include NFB because they omit it? I for one think NFB should be used with an 833. I imagine that the amp has some merits and perhaps an innovative circuit. One thing for sure is the obstacle of the OPT. It must be something to behold. I wonder if such an amp without all the exotic materials is in the realm and feasibility of some of the more accomplished RATS. The OPT for 833 isn't any real big deal. One way to do 833 is to use parafeed with a couple of 10H+ chokes in series to the anode, then a Hammond OPT of 10k : 8 ohm Z ratio can be cap coupled to the anode. I helped a guy in the US go through all the numbers when he built one. He had a lot of ex-navy chokes, and his 833 amp didn't cost him anywhere near what a WAVAC will I know it's only something I can dream of. Do you think it can be home made? What would be some of the major obstacles? Building one's own anything with tubes takes knowledge, practice, skills, patience, tools, work space, and confidence and time. Patrick Turner. Also which MAC do you like? west BTW: what's your handle? |
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I look forward to reading your article. Did you wind your own OPT or
have one wound? |
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"John Stewart" wrote in message
... west wrote: You certainly know how to skirt a question. I ask you for the weather and you give me the baseball score. The question was the same one you posed to me. Show me the PROJECTS you have done recently. When was the last time you BUILT something (please give date). You can send an article from years ago to the next issue of a magazine. What have you done for me lately," as the Janet Jackson song says. west Do you see what I meant by flame? You throw out your garbage and the dogs come sniffing (Iverson) The most recent project went to the publisher Audio Amateur Magazines on May 18th this year. The project was begun in mid-February of this year. It is a 15 watt amp running PP 6V6GT's in a circuit derived from the McIntosh. There are both fixed bias & cathode bias versions of the amp. Also, your choice of a regulated PS or a common CLC type, both using a SS rectifier. There are four tables of THD & individual harmonic distortion data along with plots of IMD. Many photos of sub-assemblies, all annotated, used in it's construction. There are eight schematics. I did the proofing of the article & sent it back to the publisher on June 15, 2005. All up there are about 45 pages. The text on their version is double spaced. It is a major work. I expect it to be published sometime later this year. Why don't you spend a buck & buy yourself some back copies of those magazines? They are very informative, with good articles by many authors on these subjects. See http://www.audioxpress.com Cheers, John Stewart John, I'm sorry to say I think you are getting deeper and deeper in it. Where is the ontological proof? Although the project sounds like Newbie 101, "Adventure With Tubes," I still don't believe you. I think you just made it up to save face. Show us pixs and a diagram together with a draft of the article. Talk is cheap. Save your reputation. Besides, is this the only actual construction you have in the last several years? Show us what you been up to besides writing. Pixs can say 1000 words as the saying goes. Mid February? What before and when? Thank you for obliging us and will you please answer the other gentleman's question? Cordially, west |
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west wrote:
John, I'm sorry to say I think you are getting deeper and deeper in it. Whereis the ontological proof? Although the project sounds like Newbie 101, "Adventure With Tubes," I still don't believe you. I think you just made it up to save face. Show us pixs and a diagram together with a draft of the article. Talk is cheap. Save your reputation. Besides, is this the only actual construction you have in the last several years? Show us what you been up to besides writing. Pixs can say 1000 words as the saying goes. Mid February? What before and when? Thank you for obliging us and will you please answer the other gentleman's question? Cordially, west This is getting ridiculous, but here goes. If you would take the time please go to the following link where you willfind me listed as one of the authors. Of the 17 articles in the referenced publication I authored three of them. See http://www.audioxpress.com/bksprods/books/bkaa62.htm The latest article is aimed at those having moderate electronics experience, hopefully some of it with vacuum tubes since there can be up to 400 voltsinside the chassis. The circuit is based on the work of Norman Crowhurst in the late 50's but goes somewhat further into the subject. He used a pair of OPT's to take the place of a single bifilar wound OPT as used in the McIntosh. All of the iron used in this version are standard Hammond parts since my primary objective in all my articles has been to avoid exotic or 'boutique' components. This amp can be built for less than 200.00 USD, even while buying all the parts as newor NOS. There are no specially selected parts, yet the performance is outstanding. The article also describes how you can run the amp with or without full loop NFB & get distortion results that make SET amps seem like something that justcame off the ark! See ABSE for a photo under the heading 'Crowhurst Amp'. There is also a spectrum trace of the IMD. Here is a sample of the data given in one of the four measurement results tables- CONDITION WATTS 2H 3H 4H 5H THD Other I) 6SN7GT driver cathodes 1 0.044 0.022 0.004 ~ 0.056 DF = 9.59 through 2N3055 CC Source 3 0.038 0.033 ~ ~ 0.056 NFB = 18 db to –14 volts 10 0.029 0.012 ~ 0.0070.035 14 0.033 0.04 0.006 0.004 0.055 J) 6SN7GT driver cathodes 1 0.143 0.083 0.005 ~ 0.145 DF = 3.75 through 29 K to –160 volts 3 0.257 0.182 0.007 0.013 0.270 NFB= Zero Differential input circuit 10 0.486 0.054 0.010 0.051 0.470 14 0.571 0.213 0.046 0.030 0.580 The distortion measurements were taken using an HP 334A (THD) & a Pico Technology ADC-216 (2H to 5H & IMD). As a courtesy to the publisher I will not be posting any of the text. Forthat you will have to wait for publication. But you can easily get some idea of the circuit since I authored a similar article which was published in the August 2004 issue of AudioXpress magazine. Back copies are available thru their web site at www.audioxpress.com Hope this closes the subject for now. Cheers to all who have put up with this BS. John Stewart |
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John,
Although You still haven't answered the question, don't act like a self anointed martyr. Remember, you struck the first blow. I checked my archives and the only thing you contributed to the rather long thread regarding crossovers, was to ask the same question about my credentials. I never asked for your help. Why is it that you complain about how much time was "spent on me?" If there is a lot of time spent on a tread, can it be because it might be somewhat interesting? I'm still getting plenty of email about that subject. So for you to thank readers for putting up with the BS, It's your BS they had to put up with. Anyone with a sharp mind can see you still haven't answers the question which asked for you to demonstrate on what projects you have BUILT lately with dates. Most of us realize why you cannot deliver. I think our readership will be able to discern that perhaps you were great in your time, but your prime time has been over for some time. I regret for what happened to this thread. I don't get involved with this sort of thing, but I was in the middle of an interesting subject and you, John, once again, ripped it apart by asking for credentials. I thought this group was open to everyone. Newbie, professional, and occasionally the dog sniffers who thrive on controversy. west "John Stewart" wrote in message ... west wrote: John, I'm sorry to say I think you are getting deeper and deeper in it. Where is the ontological proof? Although the project sounds like Newbie 101, "Adventure With Tubes," I still don't believe you. I think you just made it up to save face. Show us pixs and a diagram together with a draft of the article. Talk is cheap. Save your reputation. Besides, is this the only actual construction you have in the last several years? Show us what you been up to besides writing. Pixs can say 1000 words as the saying goes. Mid February? What before and when? Thank you for obliging us and will you please answer the other gentleman's question? Cordially, west This is getting ridiculous, but here goes. If you would take the time please go to the following link where you will find me listed as one of the authors. Of the 17 articles in the referenced publication I authored three of them. See http://www.audioxpress.com/bksprods/books/bkaa62.htm The latest article is aimed at those having moderate electronics experience, hopefully some of it with vacuum tubes since there can be up to 400 volts inside the chassis. The circuit is based on the work of Norman Crowhurst in the late 50's but goes somewhat further into the subject. He used a pair of OPT's to take the place of a single bifilar wound OPT as used in the McIntosh. All of the iron used in this version are standard Hammond parts since my primary objective in all my articles has been to avoid exotic or 'boutique' components. This amp can be built for less than 200.00 USD, even while buying all the parts as new or NOS. There are no specially selected parts, yet the performance is outstanding. The article also describes how you can run the amp with or without full loop NFB & get distortion results that make SET amps seem like something that just came off the ark! See ABSE for a photo under the heading 'Crowhurst Amp'. There is also a spectrum trace of the IMD. Here is a sample of the data given in one of the four measurement results tables- CONDITION WATTS 2H 3H 4H 5H THD Other I) 6SN7GT driver cathodes 1 0.044 0.022 0.004 ~ 0.056 DF = 9.59 through 2N3055 CC Source 3 0.038 0.033 ~ ~ 0.056 NFB = 18 db to -14 volts 10 0.029 0.012 ~ 0.007 0.035 14 0.033 0.04 0.006 0.004 0.055 J) 6SN7GT driver cathodes 1 0.143 0.083 0.005 ~ 0.145 DF = 3.75 through 29 K to -160 volts 3 0.257 0.182 0.007 0.013 0.270 NFB= Zero Differential input circuit 10 0.486 0.054 0.010 0.051 0.470 14 0.571 0.213 0.046 0.030 0.580 The distortion measurements were taken using an HP 334A (THD) & a Pico Technology ADC-216 (2H to 5H & IMD). As a courtesy to the publisher I will not be posting any of the text. For that you will have to wait for publication. But you can easily get some idea of the circuit since I authored a similar article which was published in the August 2004 issue of AudioXpress magazine. Back copies are available thru their web site at www.audioxpress.com Hope this closes the subject for now. Cheers to all who have put up with this BS. John Stewart |
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#30
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west wrote:
Fellow Rodents, Anyone know where to find schematics (save World Tube Audio) for an amp utilizing the 833 transmitter tube? Perhaps you have some experience with this tube that you might want to share? All comments welcomed. Cordially, west The answer to all this crap that has been posted is something like this: It's a tube, ergo you can build an amp around it. There are design problems with the 833 that need to be taken into account - therefore it's not a good newbie project. --- Interstage transformers and similar and related methods are out there to provide copious amounts of drive in Class 2 (grid current) situations. Pick one or more. You can always run the tube at reduced plate voltage and it will still work, eh? You can also pick easier tubes to build up, drive and run, like the 845 or 211 and get similar power levels even if you have to parallel them. No number of 6550s or 6L6s in PP parallel will ever sound anything like a triode, not in PP and certainly not in SE... even if you may like or prefer their sound over triodes. A single 833 will make one heck of a lot more power than a 2A3 or 300B, not matter what you do wrong (probably). 833s need special sockets - but you can make ur own. 833s GLOW very nicely. A plus! :- ) My feeling is this: If you need a schematic to build an 833 amp, don't. You can send ur extra 833s here, if you wish, I can use them for audio or RF, both or either. :_) (I may have forgotten something... but it doesn't really matter.) _-_-bear |
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John Stewart wrote: west wrote: John, I'm sorry to say I think you are getting deeper and deeper in it. Where is the ontological proof? Although the project sounds like Newbie 101, "Adventure With Tubes," I still don't believe you. I think you just made it up to save face. Show us pixs and a diagram together with a draft of the article. Talk is cheap. Save your reputation. Besides, is this the only actual construction you have in the last several years? Show us what you been up to besides writing. Pixs can say 1000 words as the saying goes. Mid February? What before and when? Thank you for obliging us and will you please answer the other gentleman's question? Cordially, west This is getting ridiculous, but here goes. If you would take the time please go to the following link where you will find me listed as one of the authors. Of the 17 articles in the referenced publication I authored three of them. See http://www.audioxpress.com/bksprods/books/bkaa62.htm The latest article is aimed at those having moderate electronics experience, hopefully some of it with vacuum tubes since there can be up to 400 volts inside the chassis. The circuit is based on the work of Norman Crowhurst in the late 50's but goes somewhat further into the subject. He used a pair of OPT's to take the place of a single bifilar wound OPT as used in the McIntosh. All of the iron used in this version are standard Hammond parts since my primary objective in all my articles has been to avoid exotic or 'boutique' components. This amp can be built for less than 200.00 USD, even while buying all the parts as new or NOS. There are no specially selected parts, yet the performance is outstanding. The article also describes how you can run the amp with or without full loop NFB & get distortion results that make SET amps seem like something that just came off the ark! See ABSE for a photo under the heading 'Crowhurst Amp'. There is also a spectrum trace of the IMD. Here is a sample of the data given in one of the four measurement results tables- CONDITION WATTS 2H 3H 4H 5H THD Other I) 6SN7GT driver cathodes 1 0.044 0.022 0.004 ~ 0.056 DF = 9.59 through 2N3055 CC Source 3 0.038 0.033 ~ ~ 0.056 NFB = 18 db to –14 volts 10 0.029 0.012 ~ 0.007 0.035 14 0.033 0.04 0.006 0.004 0.055 J) 6SN7GT driver cathodes 1 0.143 0.083 0.005 ~ 0.145 DF = 3.75 through 29 K to –160 volts 3 0.257 0.182 0.007 0.013 0.270 NFB= Zero Differential input circuit 10 0.486 0.054 0.010 0.051 0.470 14 0.571 0.213 0.046 0.030 0.580 The distortion measurements were taken using an HP 334A (THD) & a Pico Technology ADC-216 (2H to 5H & IMD). As a courtesy to the publisher I will not be posting any of the text. For that you will have to wait for publication. But you can easily get some idea of the circuit since I authored a similar article which was published in the August 2004 issue of AudioXpress magazine. Back copies are available thru their web site at www.audioxpress.com Hope this closes the subject for now. Cheers to all who have put up with this BS. John Stewart But the builders of fine SET amps don't consider their work to be BS. In fact they don't like PP amps with NFB. Now if you take away the NFB including the local NFB in the OPT arrangment your above $200 amps the THD will be somewhat not so good, with worse spectra than the SET which came off the "ark", as you suggest. There is of course no reason why the SE amp could not have some NFB applied and thus will measure very much better. Some ppl just enjoy the expense and danger of amps using 1,200v for the plate supply; they reckon the sound is purer, despite a bit of 2H, usually less than 1% at normal listeing levels. Having heard quite a few SET amps that so many other people might condemn for poor technical performance, I have to say that the sound is quite excellent from most. The fact would remain that should not upset anyone, that design samples from Crowshurst, Williamson, Peter Walker, and McIntosh in the west, and all those designers of Japanese SET amps in the east do have the ability to delight a lotta people. As far as I know, the Crowshurst idea with two el cheapo OPTs and which does allow cheap sound, has been in your barrow that you push for goodness knows how many years. I might add that an ordinary UL amp using a pair of KT88 PP with a mere 16 db of global FB can produce no more than 0.1% thd at 35 watts using one well designed OPT. To get over twice the power at one fifth of the thd than the test results you quote above does cost a little more than $200, but permit most audiophiles the luxurious choice they make for far better overall performance, albeit at 6 times the diy price. But the audiophiles go to even further expense per watt, and choose SET, and although this seems ludicrous, leave them to it, they know what they are doing. They may be of different faiths, but they are all God's children. Patrick Turner. |
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#32
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"Patrick Turner" wrote in message
... John Stewart wrote: west wrote: John, I'm sorry to say I think you are getting deeper and deeper in it. Where is the ontological proof? Although the project sounds like Newbie 101, "Adventure With Tubes," I still don't believe you. I think you just made it up to save face. Show us pixs and a diagram together with a draft of the article. Talk is cheap. Save your reputation. Besides, is this the only actual construction you have in the last several years? Show us what you been up to besides writing. Pixs can say 1000 words as the saying goes. Mid February? What before and when? Thank you for obliging us and will you please answer the other gentleman's question? Cordially, west This is getting ridiculous, but here goes. If you would take the time please go to the following link where you will find me listed as one of the authors. Of the 17 articles in the referenced publication I authored three of them. See http://www.audioxpress.com/bksprods/books/bkaa62.htm The latest article is aimed at those having moderate electronics experience, hopefully some of it with vacuum tubes since there can be up to 400 volts inside the chassis. The circuit is based on the work of Norman Crowhurst in the late 50's but goes somewhat further into the subject. He used a pair of OPT's to take the place of a single bifilar wound OPT as used in the McIntosh. All of the iron used in this version are standard Hammond parts since my primary objective in all my articles has been to avoid exotic or 'boutique' components. This amp can be built for less than 200.00 USD, even while buying all the parts as new or NOS. There are no specially selected parts, yet the performance is outstanding. The article also describes how you can run the amp with or without full loop NFB & get distortion results that make SET amps seem like something that just came off the ark! See ABSE for a photo under the heading 'Crowhurst Amp'. There is also a spectrum trace of the IMD. Here is a sample of the data given in one of the four measurement results tables- CONDITION WATTS 2H 3H 4H 5H THD Other I) 6SN7GT driver cathodes 1 0.044 0.022 0.004 ~ 0.056 DF = 9.59 through 2N3055 CC Source 3 0.038 0.033 ~ ~ 0.056 NFB = 18 db to -14 volts 10 0.029 0.012 ~ 0.007 0.035 14 0.033 0.04 0.006 0.004 0.055 J) 6SN7GT driver cathodes 1 0.143 0.083 0.005 ~ 0.145 DF = 3.75 through 29 K to -160 volts 3 0.257 0.182 0.007 0.013 0.270 NFB= Zero Differential input circuit 10 0.486 0.054 0.010 0.051 0.470 14 0.571 0.213 0.046 0.030 0.580 The distortion measurements were taken using an HP 334A (THD) & a Pico Technology ADC-216 (2H to 5H & IMD). As a courtesy to the publisher I will not be posting any of the text. For that you will have to wait for publication. But you can easily get some idea of the circuit since I authored a similar article which was published in the August 2004 issue of AudioXpress magazine. Back copies are available thru their web site at www.audioxpress.com Hope this closes the subject for now. Cheers to all who have put up with this BS. John Stewart But the builders of fine SET amps don't consider their work to be BS. In fact they don't like PP amps with NFB. Now if you take away the NFB including the local NFB in the OPT arrangment your above $200 amps the THD will be somewhat not so good, with worse spectra than the SET which came off the "ark", as you suggest. There is of course no reason why the SE amp could not have some NFB applied and thus will measure very much better. Some ppl just enjoy the expense and danger of amps using 1,200v for the plate supply; they reckon the sound is purer, despite a bit of 2H, usually less than 1% at normal listeing levels. Having heard quite a few SET amps that so many other people might condemn for poor technical performance, I have to say that the sound is quite excellent from most. The fact would remain that should not upset anyone, that design samples from Crowshurst, Williamson, Peter Walker, and McIntosh in the west, and all those designers of Japanese SET amps in the east do have the ability to delight a lotta people. As far as I know, the Crowshurst idea with two el cheapo OPTs and which does allow cheap sound, has been in your barrow that you push for goodness knows how many years. I might add that an ordinary UL amp using a pair of KT88 PP with a mere 16 db of global FB can produce no more than 0.1% thd at 35 watts using one well designed OPT. To get over twice the power at one fifth of the thd than the test results you quote above does cost a little more than $200, but permit most audiophiles the luxurious choice they make for far better overall performance, albeit at 6 times the diy price. But the audiophiles go to even further expense per watt, and choose SET, and although this seems ludicrous, leave them to it, they know what they are doing. They may be of different faiths, but they are all God's children. Patrick Turner. Thanks Patrick for getting this tread back on track with a very interesting post. I don't know why so many seem almost ashamed for using feedback. Some brag that their design uses no feedback as if it were a merit of honor. I was impressed that you gave me a complete schematic of an 833 SE amp after only one post. Did you just make it up or did you have it already? What would you do besides a bigger PS to make that tube push 100 - 150 watts. Can the OPT be purchased or has to be custom made? Thanks. west |
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#33
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Patrick Turner wrote:
But the builders of fine SET amps don't consider their work to be BS. In fact they don't like PP amps with NFB. Now if you take away the NFB including the local NFB in the OPT arrangment Did you notice one set of data I posted is with no loop NFB. Only local NFB & that is an important property of this circuit. While in that mode the performance it is still impressive. A while ago we talked about how triodes have local NFB. There seems to be some small similarity here. your above $200 amps the THD will be somewhat not so good, with worse spectra than the SET which came off the "ark", as you suggest. All you say is true, of course. Looking at the measured performance I can think of many ways of getting those kind of results from an SET circuit. However, the point is the circuit I described can be built with excellent results by many for only 200.00 USD. That is not the case with an equivalent SET. I'm sure you are very aware of that. Remember, you will need 14 watts, DF about 4, THD less than one percent, no loop NFB & get there while not spending more than 200.00 USD. And take a look at the IMD trace of 60 & 7000 Hz over at ABSE. That will be difficult to match with a low cost SET. Good Luck, John Stewart |
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west wrote: "Patrick Turner" wrote in message ... John Stewart wrote: west wrote: John, I'm sorry to say I think you are getting deeper and deeper in it. Where is the ontological proof? Although the project sounds like Newbie 101, "Adventure With Tubes," I still don't believe you. I think you just made it up to save face. Show us pixs and a diagram together with a draft of the article. Talk is cheap. Save your reputation. Besides, is this the only actual construction you have in the last several years? Show us what you been up to besides writing. Pixs can say 1000 words as the saying goes. Mid February? What before and when? Thank you for obliging us and will you please answer the other gentleman's question? Cordially, west This is getting ridiculous, but here goes. If you would take the time please go to the following link where you will find me listed as one of the authors. Of the 17 articles in the referenced publication I authored three of them. See http://www.audioxpress.com/bksprods/books/bkaa62.htm The latest article is aimed at those having moderate electronics experience, hopefully some of it with vacuum tubes since there can be up to 400 volts inside the chassis. The circuit is based on the work of Norman Crowhurst in the late 50's but goes somewhat further into the subject. He used a pair of OPT's to take the place of a single bifilar wound OPT as used in the McIntosh. All of the iron used in this version are standard Hammond parts since my primary objective in all my articles has been to avoid exotic or 'boutique' components. This amp can be built for less than 200.00 USD, even while buying all the parts as new or NOS. There are no specially selected parts, yet the performance is outstanding. The article also describes how you can run the amp with or without full loop NFB & get distortion results that make SET amps seem like something that just came off the ark! See ABSE for a photo under the heading 'Crowhurst Amp'. There is also a spectrum trace of the IMD. Here is a sample of the data given in one of the four measurement results tables- CONDITION WATTS 2H 3H 4H 5H THD Other I) 6SN7GT driver cathodes 1 0.044 0.022 0.004 ~ 0.056 DF = 9.59 through 2N3055 CC Source 3 0.038 0.033 ~ ~ 0.056 NFB = 18 db to -14 volts 10 0.029 0.012 ~ 0.007 0.035 14 0.033 0.04 0.006 0.004 0.055 J) 6SN7GT driver cathodes 1 0.143 0.083 0.005 ~ 0.145 DF = 3.75 through 29 K to -160 volts 3 0.257 0.182 0.007 0.013 0.270 NFB= Zero Differential input circuit 10 0.486 0.054 0.010 0.051 0.470 14 0.571 0.213 0.046 0.030 0.580 The distortion measurements were taken using an HP 334A (THD) & a Pico Technology ADC-216 (2H to 5H & IMD). As a courtesy to the publisher I will not be posting any of the text. For that you will have to wait for publication. But you can easily get some idea of the circuit since I authored a similar article which was published in the August 2004 issue of AudioXpress magazine. Back copies are available thru their web site at www.audioxpress.com Hope this closes the subject for now. Cheers to all who have put up with this BS. John Stewart But the builders of fine SET amps don't consider their work to be BS. In fact they don't like PP amps with NFB. Now if you take away the NFB including the local NFB in the OPT arrangment your above $200 amps the THD will be somewhat not so good, with worse spectra than the SET which came off the "ark", as you suggest. There is of course no reason why the SE amp could not have some NFB applied and thus will measure very much better. Some ppl just enjoy the expense and danger of amps using 1,200v for the plate supply; they reckon the sound is purer, despite a bit of 2H, usually less than 1% at normal listeing levels. Having heard quite a few SET amps that so many other people might condemn for poor technical performance, I have to say that the sound is quite excellent from most. The fact would remain that should not upset anyone, that design samples from Crowshurst, Williamson, Peter Walker, and McIntosh in the west, and all those designers of Japanese SET amps in the east do have the ability to delight a lotta people. As far as I know, the Crowshurst idea with two el cheapo OPTs and which does allow cheap sound, has been in your barrow that you push for goodness knows how many years. I might add that an ordinary UL amp using a pair of KT88 PP with a mere 16 db of global FB can produce no more than 0.1% thd at 35 watts using one well designed OPT. To get over twice the power at one fifth of the thd than the test results you quote above does cost a little more than $200, but permit most audiophiles the luxurious choice they make for far better overall performance, albeit at 6 times the diy price. But the audiophiles go to even further expense per watt, and choose SET, and although this seems ludicrous, leave them to it, they know what they are doing. They may be of different faiths, but they are all God's children. Patrick Turner. Thanks Patrick for getting this tread back on track with a very interesting post. I don't know why so many seem almost ashamed for using feedback. Some brag that their design uses no feedback as if it were a merit of honor. I was impressed that you gave me a complete schematic of an 833 SE amp after only one post. Did you just make it up or did you have it already? The schematic is a design that I recently sent to a colleague who had a customer who wanted an 833 amp. The project didn't go ahead though, which often happens with "customer dreams." He builds more amps than I do, but I do all his critical OPT and schematic design work. What would you do besides a bigger PS to make that tube push 100 - 150 watts. Can the OPT be purchased or has to be custom made? Thanks. There is a pp Hammond OPT which can be used, if you settle for parafeed. This means there is *no* need for a special OPT suited to DC flow, which for a given power level for a given RL will have more primary. turns and a larger but gapped core. The Hammond is the cheap option. Anything custom will cost more. The 833 draws grid current, and unlike 211, 845, GM70 etc, it can't be used in class A1, and can only run class A2. It also has far higher Ra than the other listed tubes but it does have much greater gain, and is quite easy to drive in terms of voltage compared to say an 845. So because the Ra is so high, Ra approximately = RL, so thei would mean the Ro at the OPT sec might = 8 ohms, and also = to the speaker load, so damping factor is a poor 1.0, approx. Therefore NFB is essential if a flat response is required because just about all speakers have a huge variation in Z, your saga with your Infinitys ( dare I mention them ) surely brings home the idea that Z varies. The maximum efficiency of a tube like the 833 is like that of a tetrode or pentode, ie, about 40% maximum because of the ability of the anode to swing negative further under grid current than other tubes operating in class A1, where anode swing is limited by the Ra line where Eg1 = 0V. BTW, a 6L6 can make 6 watts in triode A1, but if set up with a CF driver it can make about 9 watts in triode class A2, almost as much as beam tetrode mode; nobody ever does this because the extra 3 watts costs an extra CF driver triode. The 833 grid is biased near 0V, so all +ve grids swings draws grid current, so hence the need for the CF buffer driver tube. Ig1 always causes some distortion, even with a CF buffer. Its another reason for the NFB. Now the 833 has a greater plate dissipation ability than most other glass tubes, around 400watts, but i'd never run it at that sort of power without a fan, which is OK in a transmitter, but intolerable in a loungeroom. But even if you did and efficiency was 40%, then you'd get only 160 watts of power. WAVAC get around 100 watts, do they not? So they must be running the tube quite warm at around 250 watts. I just keep thinking that there are not many 833 replacements around, so why run such a "precious" tube so hard? So ***before*** deciding on building anything like this it would be beneficial to measure what power is needed, and this time I will not insist that you find that out since the last time I insisted that you measure your power requrirements and speaker impedance it did appear that I may have just as well insisted that the White House might move all by itself to Alaska ;-] Patrick Turner. west |
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John Stewart wrote: Patrick Turner wrote: But the builders of fine SET amps don't consider their work to be BS. In fact they don't like PP amps with NFB. Now if you take away the NFB including the local NFB in the OPT arrangment Did you notice one set of data I posted is with no loop NFB. Only local NFB & that is an important property of this circuit. While in that mode the performance it is still impressive. It would be, the local NFB is a lot of NFB. With that removed, and then compared to the SET, the SET is a better performer. A while ago we talked about how triodes have local NFB. There seems to be some small similarity here. True, some triodes have more than others, but all have an amount of NFB that is applied differently to any external loop we might devise around a beam tetrode. your above $200 amps the THD will be somewhat not so good, with worse spectra than the SET which came off the "ark", as you suggest. All you say is true, of course. Looking at the measured performance I can think of many ways of getting those kind of results from an SET circuit. However, the point is the circuit I described can be built with excellent results by many for only 200.00 USD. That is not the case with an equivalent SET. I'm sure you are very aware of that. Remember, you will need 14 watts, DF about 4, THD less than one percent, no loop NFB & get there while not spending more than 200.00 USD. And take a look at the IMD trace of 60 & 7000 Hz over at ABSE. That will be difficult to match with a low cost SET. Measurements don't mean very much to audiophiles using SET. They usually use such amps in their region of power where thd/imd is at negligible levels. As I pointed out in the rest of the post I made, SET is always going to cost more, but just because an amp costs $200 will not make it universally appealing to all; in fact many audiophiles will be very suspect, so its only the povety striken types that will build your design. Anyone with a few $$$ and a few brain cells will see that better could be achieved, and its impossible to market $200 amps to some folks. It seems irrational, but there are also no new cars on the market costing $5,000 that are worth buying. There should be of course, but I don't see any. Patrick Turner. Good Luck, John Stewart |
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No but people in the UK, I don't know about Australia and the UK, can
buy Japanese used cars at a colossal discount since there is an "inspection" there that is not cost effective to perform so they scrap or deport them. Japan is the only non-English speaking country to persist in driving on the incorrect side of the road AFAIK, therefore they are a RHD market. In the US having a RHD "ricer" is a status symbol for some subcultures so they will get the dash and steering rack from a junked domestic market car and swap them out, much cheaper than our Nazi-like EPA and DOT bull**** to import the whole car. |
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I meant to say Australia and New Zealand.
Anyway, I'm surprised they just don't drive English cars there, because they are not as bad as people think they are if you sort them out (i.e. get rid of the Lucas garbage). |
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Patrick Turner wrote:
As far as I know, the Crowshurst idea with two el cheapo OPTs and which does allow cheap sound, has been in your barrow that you push for goodness knows how many years. Yes! Goodness knows (your words) only a year & a half since I decided to attempt this particular topology. But I'm so old I do recall the original articles beginning in 1957. I had lost track of the circuit but got copies of all three articles from Bill Perkins of PEARL about 12 years ago. I was curious so I finally tried one. The results were so much better than the many other circuits including UL of similar cost I had tried over the years. I've recently completed the 2nd. The results again exceeded my expectations. I might add that an ordinary UL amp using a pair of KT88 PP with a mere 16 db of global FB can produce no more than 0.1% thd at 35 watts using one well designed OPT. To get over twice the power at one fifth of the thd than the test results you quote above does cost a little more than $200, but permit most audiophiles the luxurious choice they make for far better overall performance, albeit at 6 times the diy price. But the audiophiles go to even further expense per watt, and choose SET, and although this seems ludicrous, leave them to it, they know what they are doing. As always, we should expect that throwing money at the project should result in some performance improvements. And they will with Crowhurst's circuit just as they do with any other circuit you might choose. That is a sure thing if properly executed. My articles are directed to ordinary folks who may not have thousands of dollars to gamble on a home built circuit that may fail & possibly kill them as a bonus. The money & effort available needs to be evenly spread over the whole sound system, not just the amplifier. But if it makes you feel more secure to criticize Crowhurst's work, please do. At times your arguments don't even make sense but I read them anyway! They may be of different faiths, but they are all God's children. Patrick Turner. BTW, my earlier reference to BS had absolutely nothing to do with SET amps as you have erroneously reported. Those are your words. Better go back & carefully read what I said. Not sure how you managed to read that into the thread. I was referring to the seeming inability of Westley to comprehend my responses to his query. And that is still a mystery to anyone, IMO! Cheers, John Stewart |
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Patrick Turner wrote:
Thanks Patrick for getting this tread back on track with a very interesting post. I don't know why so many seem almost ashamed for using feedback. Some brag that their design uses no feedback as if it were a merit of honor. I was impressed that you gave me a complete schematic of an 833 SE amp after only one post. Did you just make it up or did you have it already? The schematic is a design that I recently sent to a colleague who had a customer who wanted an 833 amp. The project didn't go ahead though, which often happens with "customer dreams." He builds more amps than I do, but I do all his critical OPT and schematic design work. What would you do besides a bigger PS to make that tube push 100 - 150 watts. Can the OPT be purchased or has to be custom made? Thanks. There is a pp Hammond OPT which can be used, if you settle for parafeed. This means there is *no* need for a special OPT suited to DC flow, which for a given power level for a given RL will have more primary. turns and a larger but gapped core. That simply moves the problem from the OPT to the choke. Any choke used will need to be properly gapped & be free from parasitic resonances. Don't bother trying a PS choke. JLS The Hammond is the cheap option. Anything custom will cost more. |
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