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#41
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On Sat, 12 Mar 2005 02:38:09 GMT, Chris Hornbeck
wrote: On Thu, 10 Mar 2005 18:14:43 +0000 (UTC), Stewart Pinkerton wrote: Not surprisingly, on www.imageshack.us I'm way too dumb to be able to work this site. But I'd like to see the proposed topology. I also posted it in this thread, as a .jpeg. Please, everyone, never post binaries to a text newsgroup. It's a violation of the charter, and terribly rude. Also, many ISP's will strip anyway. Thanks, If the .jpg is a reasonable size, would you consider emailing it to interested folks? If so, include me in. It's on alt.binaries.schematics.electronic, under KISASS. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#42
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On Fri, 11 Mar 2005 23:01:36 +0100, Sander deWaal
wrote: Stewart Pinkerton said: **** off, clown, imageshack was Sander's suggestion. Yup, after placing the files on Imageshack, it's considered good practice to post the clickable URL (at the bottom of the page) on the newsgroup in order for people to actually see them ;-) Indeed, although it's now on alt.binaries.schematics.electronic under KISASS. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#43
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"Chris Hornbeck" wrote in message ... If the .jpg is a reasonable size, would you consider emailing it to interested folks? If so, include me in. Thanks, Chris Hornbeck Put me on the e-mail list too please. Also a set of test results would be of interest. Cordially, Iain |
#44
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On Sat, 12 Mar 2005 08:42:34 +0000 (UTC), Stewart Pinkerton
wrote: It's on alt.binaries.schematics.electronic, under KISASS. Great, got it. Looks fine. The lack of long loop feedback seems promising. Chris Hornbeck |
#45
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On Sat, 12 Mar 2005 12:55:26 +0200, "Iain M Churches"
wrote: "Chris Hornbeck" wrote in message .. . If the .jpg is a reasonable size, would you consider emailing it to interested folks? If so, include me in. Thanks, Chris Hornbeck Put me on the e-mail list too please. Also a set of test results would be of interest. It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#46
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John Byrns wrote: In article , Stewart Pinkerton wrote: On Wed, 09 Mar 2005 11:40:00 -0600, (John Byrns) wrote: As Easter approaches I am reminded that back in mid December Stewart Pinkerton said with respect to his "KISASS" solid state amp, designed to compete with Andre's "KISS 123" 300B tube amp, that "It's also the case that the final design is unlikely to be posted before Easter, since this is not a trivial exercise". I wonder if Stewart has any progress to report, and what the target date for a complete report on his "KISASS" design might now be, or if perhaps he has found that a design within the guidelines is beyond his capabilities, and he is hoping that we will all forget about his boast? I don't boast, nor do I use inappropriate technologies. At Sander's suggestion, I posted this design on imageshack.us weeks ago. Here it is again. BTW, it is *not* intended as any kind of competition, simply a SS alternative following the same 'minimalist' design principles of having predominantly SE nonlinearity, minimal parts count, Class A operation, less than ten watts output, and no global NFB. If you want an optimum simple SS design of similar output power, then the original Linsley Hood design is it. Now that *was* a compettitive design, designed specifically to compete with the legendary Williamson valve amp. I'll be happy to discuss the particularities of the design once everyone's had a look at the circuit. Interesting, it's not quite what I expected from you though. It looks like you got a good buy on power supply capacitors! The emitter followers were always OK with me, and I expected that you would use a push pull output stage, but I didn't think it would be quite so overt. I accept your PP output stage as being within the spirit of the competition though, since the rest of the design is so funky, and you kept the transistor count within reason. I have to wonder how stable the voltage at the output node connected to C4 is, with variations temperature and in transistor beta? Do the values of R2 & R3 have to be adjusted to suit the actual transistors used? What load impedance is it designed to drive, and what is the power output and distortion into that load? It would be nice to know a few of the basic operating parameters such as the voltage at the collector of Tr3 as well as the static current through Tr2 and Tr3/4. Designs similar to this were quite popular back in the 1960's, except that they were usually biased for class AB operation, didn't use so many capacitors in the power supply, and included an over all negative feedback loop, which also helped to stabilize the operating point. In fact I have a stereo version of one down in the basement that I built 38 years ago, I will have to dust it off and give it a listen. I even made the power transformer by rewinding the secondary of an existing transformer to give the voltage I wanted. I stuck with a true single ended output stage in all the versions of my KISSASS amplifier, and didn't use any emitter followers, but I did use an over all negative feedback loop in all three versions, which I felt was necessary to stabilize the operating point. None of the first three versions were quite what I wanted, I may have to try another. Regards, John Byrns Surf my web pages at, http://users.rcn.com/jbyrns/ I continue to have the worst possible access to ABSE from my ISP. Could somebody email me a copy of the Kissass.jpg amplifier? Patrick Turner. |
#47
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On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote: Could somebody email me a copy of the Kissass.jpg amplifier? I've reduced it to 800x600 and sent it to you. Chris Hornbeck |
#48
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Chris Hornbeck wrote: On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner wrote: Could somebody email me a copy of the Kissass.jpg amplifier? I've reduced it to 800x600 and sent it to you. Chris Hornbeck Many thanks, Patrick Turner. |
#49
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"Patrick Turner" wrote in message ... Chris Hornbeck wrote: On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner wrote: Could somebody email me a copy of the Kissass.jpg amplifier? I've reduced it to 800x600 and sent it to you. Chris Hornbeck Many thanks, Patrick Turner. I have not been able to get it either. Would some kind soul please e-mail it to me. I asked SP to do so, but without response. Iain |
#50
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Iain M Churches wrote: "Patrick Turner" wrote in message ... Chris Hornbeck wrote: On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner wrote: Could somebody email me a copy of the Kissass.jpg amplifier? I've reduced it to 800x600 and sent it to you. Chris Hornbeck Many thanks, Patrick Turner. I have not been able to get it either. Would some kind soul please e-mail it to me. I asked SP to do so, but without response. Iain I just sent you a copy. Patrick Turner. |
#51
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On Sun, 13 Mar 2005 14:20:13 +0200, "Iain M Churches"
wrote: "Patrick Turner" wrote in message ... Chris Hornbeck wrote: On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner wrote: Could somebody email me a copy of the Kissass.jpg amplifier? I've reduced it to 800x600 and sent it to you. Chris Hornbeck Many thanks, Patrick Turner. I have not been able to get it either. Would some kind soul please e-mail it to me. I asked SP to do so, but without response. I already told you that it's on alt.binaries.schematics.electronic, under KISASS. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#52
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Stewart Pinkerton wrote: On Sun, 13 Mar 2005 14:20:13 +0200, "Iain M Churches" wrote: "Patrick Turner" wrote in message ... Chris Hornbeck wrote: On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner wrote: Could somebody email me a copy of the Kissass.jpg amplifier? I've reduced it to 800x600 and sent it to you. Chris Hornbeck Many thanks, Patrick Turner. I have not been able to get it either. Would some kind soul please e-mail it to me. I asked SP to do so, but without response. I already told you that it's on alt.binaries.schematics.electronic, under KISASS. Pinky, many folks have very poor service from ISPs that don't seem able to give reliable access to weird wacko spurious old fart news groups like ABSE. Or if ABSE is accessable, often its a week behind, or the binary posts are never posted, and only the text posts are there, or people outside a country cannot have what they post seen. The system is simply not ****kin working. I have nothing but trouble with ISPs over the last 12 mths for decent binaries delivery from ABSE. Same goes for alt.binaries.pictures.radio, where schematics can also be posted. Three ISPs so far swore they'd be able to give me reliable free access to news groups, but not one has succeeded. Meanwhile access to alt.binaries.pictures.erotica.blondes NEVER is interrupted; its always OK, because about 1/3 of all net traffic is to that one site. So we are back to the grape vine, where distribution of schematics is via generosity and co-operation between individuals. If you had a website, things like that can be posted there. I may include a section at my website for such ideas and some of the pertinent discussion comments if i ever find the time to fiddle with my website to upgrade it since its long overdue. Patrick Turner. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#53
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"Stewart Pinkerton" wrote in message ... It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. I was interested to build your design for audible comparison with Andre's 300B. So this morning I took your drawing to the broadcast lab for their comments. The chief engineer looked at the schematic and said " It is normal practice to stipulate the devices used in any circuit" He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ho hum:-) Iain |
#54
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On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches"
wrote: "Stewart Pinkerton" wrote in message .. . It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. I was interested to build your design for audible comparison with Andre's 300B. So this morning I took your drawing to the broadcast lab for their comments. The chief engineer looked at the schematic and said " It is normal practice to stipulate the devices used in any circuit" He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ho hum:-) Iain Time to hire a new chief engineer, methinks! d Pearce Consulting http://www.pearce.uk.com |
#55
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"Don Pearce" wrote in message ... Time to hire a new chief engineer, methinks! Like yourself, Don, he is a digital network engineer, an area in which attention to detail is normally regarded as a positive attribute. Iain |
#56
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Iain M Churches wrote: "Stewart Pinkerton" wrote in message ... It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. I was interested to build your design for audible comparison with Andre's 300B. So this morning I took your drawing to the broadcast lab for their comments. The chief engineer looked at the schematic and said " It is normal practice to stipulate the devices used in any circuit" He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ho hum:-) Iain I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. There is a 4.7 ohm R leading from the diode bridge to the first 10,000 uF. I cannot see why he'd do that, but its OK, because although that seems queer, it won't dissallow the circuit to work, it'd just make the B+ very poorly regulated. which is quite OK with a class A amp, and even not a bad idea if a rail shorts, or a speaker shorts, because then the 4.7 ohm R will have a large voltage across it, and burn out, perhaps saving the transistor. But he led me astray with no selection of transistors. And analysis reveals that for best operation very high current gain bjts are required for the outputs. But anyway a class A emitter follower driver buffer would be a good idea to lower the impedance of the output stage driver to a few ohms at most, or less than 1 ohm, 1/ Gm, in fact. Then he'd get Rout to have been well below the 1 ohm he has, and the 70 dB of local emitter follower series voltage NFB would be far more effective. The input stage could be a single gain bjt with current FB and low gain and therefore give a high enough Rin for any preamp. I think the input emitter follower buffer is wrongly placed, and should be between the gain stage and EF output stage. Then he could make the emitter resistors of the output stage up to 1 ohm each, and Rout would still be about only 0.5 ohms. If you read old Wireless world articles, a few samples of class A bjt designs with no global FB were published, and they relied on the bags of emitter follower NFB available. In higher powered amps where one wants say 100watts into 8 ohms, we need about 29vrms into the emitter follower output stage. Ideas about cost and economy dictate class aB, with only milliwatss of class A. Therfore the main pirpose of the necessary applied global NFB is to linearize the not so wonderful VAS powering the output. In the last 300w/channel amp I built on this basis, i had about a total of 110 db of NFB, with about 50 db of that in the EF output stage, and the rest to linearize the driver stage by global means. At 10 watts the thd is about 0.002% which is about what my oscillator makes. The class A EF buffer drioving the output stage was still in there though, and its use kept thd 20 db below where it otherwise would have been. The amp I made for a dude before Xmas had 10 output transistors per channel, MJL2193/94, so the amp has a capacity for enormous instantaneous current ability, but one does not hear anything special at normal levels. Just how cleanly an SS amp is working is seen when examining the error signal, and if there is enormous thd in that signal atv the output of the input diffamp, things are not optimised. Its harder to see inside a 300B, and see its error signal, since there is NFB in the tube. But at least the 300B has just a bit of 2H, and not much else for a few watts..... Often the levels of thd in tube gear are nominated as the casue of the euphony, valve sound, warmth, rosiness, etc. But often the levels are less than 0.05%, so that argument seems limp to me. Patrick Turner. |
#57
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"Patrick Turner" wrote in message ... I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. The lab engineer was critical of what he called "mixed marking" C5 is correctly marked with the "mu" sign, while C4 is marked in milliFarads. He has clearly been following UKRA, because over a cup of coffee, he remarked "This is a schematic from the man who said that if we was in recording or broadcasting he would be the digital console designer, and yet he does not bother to mark up the simplest schematic with accuracy. No cigar!" Nevertheless, it will still be interesting to build it, and compare with the 300B. Iain |
#58
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Iain M Churches wrote: "Patrick Turner" wrote in message ... I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. The lab engineer was critical of what he called "mixed marking" C5 is correctly marked with the "mu" sign, while C4 is marked in milliFarads. He has clearly been following UKRA, because over a cup of coffee, he remarked "This is a schematic from the man who said that if we was in recording or broadcasting he would be the digital console designer, and yet he does not bother to mark up the simplest schematic with accuracy. No cigar!" Nevertheless, it will still be interesting to build it, and compare with the 300B. Interesting to some, but somehow not very exciting. Pinky just needs to package it the right language, and make a kit out of it. Maybe he'd sell squillions of them. Ill gotten gains if ever...... :-] Patrick Turner. Iain |
#59
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On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches"
wrote: "Stewart Pinkerton" wrote in message .. . It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. I was interested to build your design for audible comparison with Andre's 300B. So this morning I took your drawing to the broadcast lab for their comments. The chief engineer looked at the schematic and said " It is normal practice to stipulate the devices used in any circuit" My recommendations were separately listed, as builders may like to try various options. He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ah well, when I were a lad, the chief engineer would have had an RS or Farnell catalogue on his desk. 1, 4.7 and 10mF capacitors aren't exactly exotic components! Ho hum:-) Humdrum, even.... :-) Interesting that he apparaently had no other comments to make. Are you sure he's an actual engineer, and not a mere paper-shuffler? :-) -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#60
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On Mon, 14 Mar 2005 23:05:53 +1100, Patrick Turner
wrote: Iain M Churches wrote: "Stewart Pinkerton" wrote in message ... It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. I was interested to build your design for audible comparison with Andre's 300B. So this morning I took your drawing to the broadcast lab for their comments. The chief engineer looked at the schematic and said " It is normal practice to stipulate the devices used in any circuit" He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ho hum:-) As someone else said - time for a new chief engineer! :-) I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. That would be the 10mF, yes. There is a 4.7 ohm R leading from the diode bridge to the first 10,000 uF. I cannot see why he'd do that, but its OK, because although that seems queer, it won't dissallow the circuit to work, it'd just make the B+ very poorly regulated. which is quite OK with a class A amp, and even not a bad idea if a rail shorts, or a speaker shorts, because then the 4.7 ohm R will have a large voltage across it, and burn out, perhaps saving the transistor. Partially correct, but it also provides some isolation from HF spikes on the bridge, and gives 'soft-start' surge protection on switch-on. I agree that it's not conventional wisdom in audio amps, but this isn't a conventional amp. But he led me astray with no selection of transistors. Led you astray? They were separately listed on RAT, at least twice. And analysis reveals that for best operation very high current gain bjts are required for the outputs. Yes - that's why I used the MJL4281/4302 pair. But anyway a class A emitter follower driver buffer would be a good idea to lower the impedance of the output stage driver to a few ohms at most, or less than 1 ohm, 1/ Gm, in fact. That would be another transistor, and another stage, which is hardly adhering to KISS principles. Then he'd get Rout to have been well below the 1 ohm he has, and the 70 dB of local emitter follower series voltage NFB would be far more effective. The input stage could be a single gain bjt with current FB and low gain and therefore give a high enough Rin for any preamp. It's *supposed* to have highish output impedance, to simulate the load-dependent FR variations of a SET amp. It's also supposed to be d.c. stable and easy to build, which is why the raw gains of the BJTs haven't been pushed to eliminate the input buffer. I think the input emitter follower buffer is wrongly placed, and should be between the gain stage and EF output stage. Your opinion is noted, but I don't agree.................. Then he could make the emitter resistors of the output stage up to 1 ohm each, and Rout would still be about only 0.5 ohms. If you read old Wireless world articles, a few samples of class A bjt designs with no global FB were published, and they relied on the bags of emitter follower NFB available. In higher powered amps where one wants say 100watts into 8 ohms, we need about 29vrms into the emitter follower output stage. Ideas about cost and economy dictate class aB, with only milliwatss of class A. Therfore the main pirpose of the necessary applied global NFB is to linearize the not so wonderful VAS powering the output. I *have* built a true class A amp with 80 watts/channel into 8 ohms, but it was kinda big. It also drew about 450 watts from the wall at idle, which was handy for the Scottish climate! :-) -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#61
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On Mon, 14 Mar 2005 13:53:04 +0200, "Iain M Churches"
wrote: "Don Pearce" wrote in message ... Time to hire a new chief engineer, methinks! Like yourself, Don, he is a digital network engineer, an area in which attention to detail is normally regarded as a positive attribute. However, curiousity and initiative seem to be sadly lacking. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#62
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On Mon, 14 Mar 2005 14:32:50 +0200, "Iain M Churches"
wrote: "Patrick Turner" wrote in message ... I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. The lab engineer was critical of what he called "mixed marking" C5 is correctly marked with the "mu" sign, while C4 is marked in milliFarads. Both are correct markings, which he *should* know. Would he expect a 1k5 resistor to be marked as 1500R? Modern ISO component marking convention suggests a 3-character designation for any E12 value component, so in strict adherence I should have marked the 100mu as 0m1 - but that goes against custom and practice in the industry. He has clearly been following UKRA, because over a cup of coffee, he remarked "This is a schematic from the man who said that if we was in recording or broadcasting he would be the digital console designer, and yet he does not bother to mark up the simplest schematic with accuracy. No cigar!" This guy does not understand correct component markings, and he's your chief engineer? Nevertheless, it will still be interesting to build it, and compare with the 300B. Keep that digital klutz away from it, he's clearly at sea with analogue circuitry. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#63
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On Mon, 14 Mar 2005 23:50:26 +1100, Patrick Turner
wrote: Iain M Churches wrote: "Patrick Turner" wrote in message ... I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. The lab engineer was critical of what he called "mixed marking" C5 is correctly marked with the "mu" sign, while C4 is marked in milliFarads. He has clearly been following UKRA, because over a cup of coffee, he remarked "This is a schematic from the man who said that if we was in recording or broadcasting he would be the digital console designer, and yet he does not bother to mark up the simplest schematic with accuracy. No cigar!" This is a comment from a man who doesn't understand industry-standard component designations. Not even a Woodbine! Nevertheless, it will still be interesting to build it, and compare with the 300B. Interesting to some, but somehow not very exciting. Oh, if you cheesepare on the heatsinks or the power resistors, it could get quite exciting! Pinky just needs to package it the right language, and make a kit out of it. Maybe he'd sell squillions of them. Sorry, I'm *way* too honest for that. Not that I'm especially honest, just too honest for the SET racket, unlike say Nelson Pass, whose 'single-ended' Alpha series certainly aren't...... Ill gotten gains if ever...... :-] Indeed. Remind me - what do you charge for toob amps? :-) -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#64
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In article , Stewart Pinkerton
wrote: On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches" wrote: He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ah well, when I were a lad, the chief engineer would have had an RS or Farnell catalogue on his desk. 1, 4.7 and 10mF capacitors aren't exactly exotic components! Interesting that he apparaently had no other comments to make. Are you sure he's an actual engineer, and not a mere paper-shuffler? :-) "Paper-shuffling" is a major and time honored part of engineering, especially in union shops. It could be worse, he might be a "bit jockey". Regards, John Byrns Surf my web pages at, http://users.rcn.com/jbyrns/ |
#65
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"Stewart Pinkerton" wrote in message ... : : Sorry, I'm *way* too honest for that. Not that I'm especially honest, : just too honest for the SET racket, unlike say Nelson Pass, whose : 'single-ended' Alpha series certainly aren't...... : : Ill gotten gains if ever...... :-] : : Indeed. Remind me - what do you charge for toob amps? :-) : -- : : Stewart Pinkerton | Music is Art - Audio is Engineering ...an honest banker, playing racket ball ..developed the Nelson Pass.. drives souped up Alpha's ... ill gotten gains.. beginning to sound like a script, Pinky :-) ..the banker-detective.. a scottish tv prod. ? ;-) Rudy |
#66
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"Stewart Pinkerton" wrote in message ... Interesting that he apparaently had no other comments to make. Are you sure he's an actual engineer, and not a mere paper-shuffler? :-) I think he was singularly unimpressed:-(( He has a PhD in digital design and broadcast technology. (all the things you wish you had been?) He certainly "shuffled your paper" straight into the bin:-) Iain |
#67
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On Mon, 14 Mar 2005 13:53:04 +0200, "Iain M Churches"
wrote: "Don Pearce" wrote in message ... Time to hire a new chief engineer, methinks! Like yourself, Don, he is a digital network engineer, an area in which attention to detail is normally regarded as a positive attribute. Iain My history is that of the highest precision analogue engineering. I'm involved in digital stuff right now for the sheer fun of it. Even though I have been out of analogue engineering for a few years, I know what a 4.7mF capacitor is, and I even have a few. d Pearce Consulting http://www.pearce.uk.com |
#68
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#69
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On Mon, 14 Mar 2005 21:42:59 +0200, "Iain M Churches"
wrote: "Stewart Pinkerton" wrote in message .. . Interesting that he apparaently had no other comments to make. Are you sure he's an actual engineer, and not a mere paper-shuffler? :-) I think he was singularly unimpressed:-(( Perhaps, as is your wont, you carefully avoided mentioning (or failed to understand) the design principles. He has a PhD in digital design and broadcast technology. OK, so he knows feck all about precision analogue engineering. I once worked with a guy who gained his PhD in digital signal processing while working with Rupert Neve, and he would have been *intrigued* by KISASS, and would have been fascinated to know exactly *why* it did so many things 'wrong'. (all the things you wish you had been?) Well, granted I only picked up an MSc in digital techniques from Heriot-Watt University, because Marconi thought I should broaden my horizons from 'only analogue', and were happy to pay for it, but such is life. Digital dorks deal in ones and zeroes, analogue engineers handle *everything* from zero to infinity - and beyond! :-) He certainly "shuffled your paper" straight into the bin:-) Those who don't understand what's happening, often do that, especially if they fear that their 'position' may be undermined if they admit to bafflement. Any *real* engineer would have wondered why certain highly unorthodox design features existed, and would have enough curiosity to ask. I've met a lot of 'head of department' guys like him in my career - time for a new 'chief engineer'! -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#70
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On Mon, 14 Mar 2005 20:28:28 +0100, "Ruud Broens"
wrote: "Stewart Pinkerton" wrote in message .. . : : Sorry, I'm *way* too honest for that. Not that I'm especially honest, : just too honest for the SET racket, unlike say Nelson Pass, whose : 'single-ended' Alpha series certainly aren't...... : : Ill gotten gains if ever...... :-] : : Indeed. Remind me - what do you charge for toob amps? :-) : -- : : Stewart Pinkerton | Music is Art - Audio is Engineering ..an honest banker WHOAA! HOLD THE PHONE!!!!! I am **NOT** a banker, I only *work* for a bank. Of course, I have often been called something which sounds much the same............. playing racket ball What? Are those meds wearing off? ..developed the Nelson Pass.. Nah, I wouldn't admit to any association with that guy. Intriguingly, his best designs were those which didn't carry his name - the Adcoms. drives souped up Alpha's Actually, that bit's true. I've had three, and two of them were indeed modified. However, being an engineer, I've now graduated to souped up Audis. I didn't even tell SWMBO that her TT is chipped! :-) ... ill gotten gains.. Um, have to take the Fifth on that one! :-) beginning to sound like a script, Pinky :-) ..the banker-detective.. a scottish tv prod. ? I prefer 'The Pinkerton Man'....................... :-) But hey, I know Adam Hart-Davies from a few years back, so maybe you have something going there! -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#71
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"Stewart Pinkerton" wrote in message ... : On Mon, 14 Mar 2005 20:28:28 +0100, "Ruud Broens" : wrote: : : "Stewart Pinkerton" wrote in message : .. . : : : : Sorry, I'm *way* too honest for that. Not that I'm especially honest, : : just too honest for the SET racket, unlike say Nelson Pass, whose : : 'single-ended' Alpha series certainly aren't...... : : : : Ill gotten gains if ever...... :-] : : : : Indeed. Remind me - what do you charge for toob amps? :-) : : -- : : : : Stewart Pinkerton | Music is Art - Audio is Engineering : : ..an honest banker : : WHOAA! HOLD THE PHONE!!!!! : : I am **NOT** a banker, I only *work* for a bank. Of course, I have : often been called something which sounds much the same............. : : playing racket ball : : What? Are those meds wearing off? : : ..developed the Nelson Pass.. : : Nah, I wouldn't admit to any association with that guy. Intriguingly, : his best designs were those which didn't carry his name - the Adcoms. : : drives souped up Alpha's : : Actually, that bit's true. I've had three, and two of them were indeed : modified. However, being an engineer, I've now graduated to souped up : Audis. I didn't even tell SWMBO that her TT is chipped! :-) : : ... ill gotten gains.. : : Um, have to take the Fifth on that one! :-) : : beginning to sound like a script, Pinky :-) : ..the banker-detective.. a scottish tv prod. ? : : I prefer 'The Pinkerton Man'....................... :-) : : But hey, I know Adam Hart-Davies from a few years back, so maybe you : have something going there! : -- : : Stewart Pinkerton | Music is Art - Audio is Engineering hehe, a comedy, then ? Rudy |
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Stewart Pinkerton wrote: On Mon, 14 Mar 2005 23:05:53 +1100, Patrick Turner wrote: Iain M Churches wrote: "Stewart Pinkerton" wrote in message ... It's on alt.binaries.schematics.electronics. And it's only a paper design, so no test results. It's a simple design though, so predicting performance isn't too hard, given a decent physical layout. I was interested to build your design for audible comparison with Andre's 300B. So this morning I took your drawing to the broadcast lab for their comments. The chief engineer looked at the schematic and said " It is normal practice to stipulate the devices used in any circuit" He then looked at the caps as marked and said "We have no 4.7milliFarad electrolytic capacitors, and tossed the drawing into the bin. Ho hum:-) As someone else said - time for a new chief engineer! :-) I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. That would be the 10mF, yes. There is a 4.7 ohm R leading from the diode bridge to the first 10,000 uF. I cannot see why he'd do that, but its OK, because although that seems queer, it won't dissallow the circuit to work, it'd just make the B+ very poorly regulated. which is quite OK with a class A amp, and even not a bad idea if a rail shorts, or a speaker shorts, because then the 4.7 ohm R will have a large voltage across it, and burn out, perhaps saving the transistor. Partially correct, but it also provides some isolation from HF spikes on the bridge, and gives 'soft-start' surge protection on switch-on. I agree that it's not conventional wisdom in audio amps, but this isn't a conventional amp. But he led me astray with no selection of transistors. Led you astray? They were separately listed on RAT, at least twice. I come from Astraya, and you ppl are always leading us astray. And analysis reveals that for best operation very high current gain bjts are required for the outputs. Yes - that's why I used the MJL4281/4302 pair. But anyway a class A emitter follower driver buffer would be a good idea to lower the impedance of the output stage driver to a few ohms at most, or less than 1 ohm, 1/ Gm, in fact. That would be another transistor, and another stage, which is hardly adhering to KISS principles. No, becaue you do away with the input buffer. Then he'd get Rout to have been well below the 1 ohm he has, and the 70 dB of local emitter follower series voltage NFB would be far more effective. The input stage could be a single gain bjt with current FB and low gain and therefore give a high enough Rin for any preamp. It's *supposed* to have highish output impedance, to simulate the load-dependent FR variations of a SET amp. Why simulate anything else? Just let it be what it will be. Or else just allow the emitter resistors of the output stage to determine the Rout; its a purer way of doing it. And you'd have more class A bias stability. It's also supposed to be d.c. stable and easy to build, which is why the raw gains of the BJTs haven't been pushed to eliminate the input buffer. I think the input emitter follower buffer is wrongly placed, and should be between the gain stage and EF output stage. Your opinion is noted, but I don't agree.................. You'd be stubborn then. Then he could make the emitter resistors of the output stage up to 1 ohm each, and Rout would still be about only 0.5 ohms. If you read old Wireless world articles, a few samples of class A bjt designs with no global FB were published, and they relied on the bags of emitter follower NFB available. In higher powered amps where one wants say 100watts into 8 ohms, we need about 29vrms into the emitter follower output stage. Ideas about cost and economy dictate class aB, with only milliwatss of class A. Therfore the main pirpose of the necessary applied global NFB is to linearize the not so wonderful VAS powering the output. I *have* built a true class A amp with 80 watts/channel into 8 ohms, but it was kinda big. It also drew about 450 watts from the wall at idle, which was handy for the Scottish climate! :-) Probably as big as a 350 watt class AB amp would be. Heatsinks need to be about the same size, but yes, fine for Scottish weather. Patrick Turner. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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Stewart Pinkerton wrote: On Mon, 14 Mar 2005 23:50:26 +1100, Patrick Turner wrote: Iain M Churches wrote: "Patrick Turner" wrote in message ... I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. The lab engineer was critical of what he called "mixed marking" C5 is correctly marked with the "mu" sign, while C4 is marked in milliFarads. He has clearly been following UKRA, because over a cup of coffee, he remarked "This is a schematic from the man who said that if we was in recording or broadcasting he would be the digital console designer, and yet he does not bother to mark up the simplest schematic with accuracy. No cigar!" This is a comment from a man who doesn't understand industry-standard component designations. Not even a Woodbine! Nevertheless, it will still be interesting to build it, and compare with the 300B. Interesting to some, but somehow not very exciting. Oh, if you cheesepare on the heatsinks or the power resistors, it could get quite exciting! Pinky just needs to package it the right language, and make a kit out of it. Maybe he'd sell squillions of them. Sorry, I'm *way* too honest for that. Not that I'm especially honest, just too honest for the SET racket, unlike say Nelson Pass, whose 'single-ended' Alpha series certainly aren't...... What exactly? Ill gotten gains if ever...... :-] Indeed. Remind me - what do you charge for toob amps? :-) Less than a lot of ppl charge for SS amps. Patrick Turner. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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"Stewart Pinkerton" wrote in message ... However, curiousity and initiative seem to be sadly lacking. An alternative interpretation might be that he interests himself in better things:-)) Cordially, Iain |
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"Stewart Pinkerton" wrote in message ... Keep that digital klutz away from it, he's clearly at sea with analogue circuitry. He has designed an analogue location console used by three major broadcasting companies within EBU. He also knows enough about analogue circuitry to have recognised "your" vinyl RIAA stage as coming from a book book (either Swedish or German) or possibly an early issue of Elektor. Did the KISASS amp come from the same source? Cordially, Iain |
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"Patrick Turner" wrote in message ... I made some wrong assumptions when i looked at the schematic, but not about electros. The mF apparently are 10,000 uF. Stewart, I am going to the component shop tomorrow. Please confirm the value of C4. Thanks. Iain |
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"Stewart Pinkerton" wrote in message ... "Paper-shuffling" is a major and time honored part of engineering, especially in union shops. It could be worse, he might be a "bit jockey". Or even worse, a fader jockey! :-) Still showing a complete lack of understanding of what recording personnel actually do. But it's still better than licking the stamps:-) Iain |
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"Stewart Pinkerton" wrote in message ... On Mon, 14 Mar 2005 20:28:28 +0100, "Ruud Broens" wrote: "Stewart Pinkerton" wrote in message . .. : : Sorry, I'm *way* too honest for that. Not that I'm especially honest, : just too honest for the SET racket, unlike say Nelson Pass, whose : 'single-ended' Alpha series certainly aren't...... : : Ill gotten gains if ever...... :-] : : Indeed. Remind me - what do you charge for toob amps? :-) : -- : : Stewart Pinkerton | Music is Art - Audio is Engineering ..an honest banker WHOAA! HOLD THE PHONE!!!!! I am **NOT** a banker, I only *work* for a bank. Of course, I have often been called something which sounds much the same............. playing racket ball What? Are those meds wearing off? ..developed the Nelson Pass.. Nah, I wouldn't admit to any association with that guy. Intriguingly, his best designs were those which didn't carry his name - the Adcoms. drives souped up Alpha's Actually, that bit's true. I've had three, and two of them were indeed modified. However, being an engineer, I've now graduated to souped up Audis. I didn't even tell SWMBO that her TT is chipped! :-) ... ill gotten gains.. Um, have to take the Fifth on that one! :-) beginning to sound like a script, Pinky :-) ..the banker-detective.. a scottish tv prod. ? I prefer 'The Pinkerton Man'....................... :-) But hey, I know Adam Hart-Davies from a few years back, so maybe you have something going there! -- I once worked with a band called "Pinkerton's Assorted Colours" They used an autoharp through a guitar amp. Totally dreadful. Was that you in your younger days? :-) Iain |
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On Tue, 15 Mar 2005 11:29:32 +1100, Patrick Turner
wrote: I come from Astraya, and you ppl are always leading us astray. IIRC, we spent most of our short sojourn over there trying to ensure that you did *not* stray.................. :-) And analysis reveals that for best operation very high current gain bjts are required for the outputs. Yes - that's why I used the MJL4281/4302 pair. But anyway a class A emitter follower driver buffer would be a good idea to lower the impedance of the output stage driver to a few ohms at most, or less than 1 ohm, 1/ Gm, in fact. That would be another transistor, and another stage, which is hardly adhering to KISS principles. No, becaue you do away with the input buffer. OK, but I still prefer my original approach, I believe that it's simpler in spirit. Then he'd get Rout to have been well below the 1 ohm he has, and the 70 dB of local emitter follower series voltage NFB would be far more effective. The input stage could be a single gain bjt with current FB and low gain and therefore give a high enough Rin for any preamp. It's *supposed* to have highish output impedance, to simulate the load-dependent FR variations of a SET amp. Why simulate anything else? Just let it be what it will be. Well no, because if it's not a SS equivalent of a tube SET, it has no merit as an amplifier. Use the Linsley Hood design, for superior results and an even simpler topology. Or else just allow the emitter resistors of the output stage to determine the Rout; its a purer way of doing it. And you'd have more class A bias stability. That's pretty much what I *did* do. You can certainly increase the output emitter resistors to 1 ohm if you want the amp to be rock-stable - and you're going to avoid low impedance speakers. It's also supposed to be d.c. stable and easy to build, which is why the raw gains of the BJTs haven't been pushed to eliminate the input buffer. I think the input emitter follower buffer is wrongly placed, and should be between the gain stage and EF output stage. Your opinion is noted, but I don't agree.................. You'd be stubborn then. Oh yeah, more dig-in-ness than a Missouri mule! I think your suggestion would spoil the basic ethos, that of a central 'character determining' gain stage, with impedence transformers on either side. Then he could make the emitter resistors of the output stage up to 1 ohm each, and Rout would still be about only 0.5 ohms. If you read old Wireless world articles, a few samples of class A bjt designs with no global FB were published, and they relied on the bags of emitter follower NFB available. In higher powered amps where one wants say 100watts into 8 ohms, we need about 29vrms into the emitter follower output stage. Ideas about cost and economy dictate class aB, with only milliwatss of class A. Therfore the main pirpose of the necessary applied global NFB is to linearize the not so wonderful VAS powering the output. I *have* built a true class A amp with 80 watts/channel into 8 ohms, but it was kinda big. It also drew about 450 watts from the wall at idle, which was handy for the Scottish climate! :-) Probably as big as a 350 watt class AB amp would be. It was 18" wide, two feet deep, nine inches high, and weighed about forty kilos! Sure intimidated visitors, who assumed it must put out skull-splitting power levels! :-) -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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"Stewart Pinkerton" wrote in message ... OK, so he knows feck all about precision analogue engineering. I have replied to that in another mail. Interesting that you call your amp "precision analogue engineering" :-)))) I once worked with a guy who gained his PhD in digital signal processing while working with Rupert Neve, and he would have been *intrigued* by KISASS, and would have been fascinated to know exactly *why* it did so many things 'wrong'. I have yet to see a post where such a statement is made. Well, granted I only picked up an MSc in digital techniques from Heriot-Watt University, because Marconi thought I should broaden my horizons from 'only analogue', and were happy to pay for it, but such is life. Digital dorks deal in ones and zeroes, analogue engineers handle *everything* from zero to infinity - and beyond! :-) Surprising then that a man of your extraordinary capability has an audio system comprised entirely of other peoples engineering (with the possible exception of the vinyl pre-amp) Nothing of your own. Surprising too that a man of your extraordinary capability is working in a post room, and at only 57 years of age is "sliding into retirement" (your words) But never mind, when you retire they might pass the hat round at the bank for a down payment on a Conrad Johnson or even, if you have been a very good boy, a Radford. You can then sell the boring old Audi, to your local cab firm, and get youself a vintage motorcyle, or an early Aston and start living:-)) Iain. |
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