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#1
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
Patrick Turner, and outspoken Australian, wrote:
Being of sound mind because I do try to keep an open mind I would hazard a guess that not all of what "ultrafidelista" might hold as the truth and nothing but the truth is in fact not the truth at all and might be just a series of maybe maybe statements. Yo, Patrick, you're making the same mistake I made when I first ran into the ultrafidelista: quoting science at them. You'd do better to quote the Bible at them; have a greater effect, very likely. The hard core ultrafidelista knows what he believes in and you're wasting your breath explaining the truth to him. However, by constant practice at listening hard, and spending lots of money to extract a few gems of truth from the dross of street myths and shakti stones, the ultrafidelista have done us all a favour. I got to be a high priest of the ultrafidelista because by collecting the bits of their wisdom that had a genuine electronic basis, or simple superiority on my trained and cultured ear, I found it easy to build amps that not only sounded better but were electronically superior of their type. Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. The same applies in loudspeakers: without the ultrafidelista, the horn loudspeaker, to cite only one instance, would now be dead. Much as we might enjoy kicking around the loony cableswapping wannabes, at the serious DIY end of the ultrafidelista to which I belong there has always been a good deal of serious engineering going on, conducted by concert-goers of excellent taste. Someone has to stand up for them. Andre Jute Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ "wonderfully well written and reasoned information for the tube audio constructor" John Broskie TubeCAD & GlassWare "an unbelievably comprehensive web site containing vital gems of wisdom" Stuart Perry Hi-Fi News & Record Review |
#2
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
In article ,
Andre Jute wrote: Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. I disagree with you that bootstrap topologies belong in this group. Bootstrap topologies were and are the darling of commercial makers because they permit the construction of amplifiers with a lower cost. -- Regards, John Byrns Surf my web pages at, http://fmamradios.com/ |
#3
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
On Nov 30, 4:17*pm, John Byrns wrote:
In article , *Andre Jute wrote: Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. I disagree with you that bootstrap topologies belong in this group. *Bootstrap topologies were and are the darling of commercial makers because they permit the construction of amplifiers with a lower cost. Eh? When I mentioned bootstrap technologies, I had in mind the SRPP, which Japanese ultrafidelista kept alive all those years, a circuit for half a century so obscure that it isn't even in the RDH and is called something else in Vacuum Tube Amplifiers. How can a two-tube stage be more economical than a single tube? -- Regards, John Byrns Surf my web pages at, *http://fmamradios.com/ I don't get it. Won't be the first time... Andre Jute Always glad to learn something new |
#4
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
The "ultrafidelistas" are not fidelistas at all but "soundmodificantes".
Their goofy piles of industrial junk MODIFY the signal for a result THEY LIKE BETTER, but which is LESS FIDELIOUS to the original signal. AND THEY KNOW IT, but DON"T CARE, and will DENY it to outsiders until cornered. -- Message posted using http://www.talkaboutaudio.com/group/rec.audio.tubes/ More information at http://www.talkaboutaudio.com/faq.html |
#5
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
In article ,
Andre Jute wrote: On Nov 30, 4:17*pm, John Byrns wrote: In article , *Andre Jute wrote: Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. I disagree with you that bootstrap topologies belong in this group. *Bootstrap topologies were and are the darling of commercial makers because they permit the construction of amplifiers with a lower cost. Eh? When I mentioned bootstrap technologies, I had in mind the SRPP, which Japanese ultrafidelista kept alive all those years, a circuit for half a century so obscure that it isn't even in the RDH and is called something else in Vacuum Tube Amplifiers. How can a two-tube stage be more economical than a single tube? First I don't remember saying anything about numbers of tubes, just lower cost. Bootstrap topologies were/are often used in both tube and solid state circuits to increase the voltage output capability of an amplifier stage without resorting to the extra expense of an additional higher voltage B+ supply for the stage in question. For an example of bootstrapping in a tube amplifier, check out the push-pull voltage amplifier stage, the stage following the phase inverter, in the classic McIntosh Mc30 amplifier. Your homework assignment is to study the voltage amplifier stage of this amplifier, understand how it works, and then explain it to the class so that those less gifted than you may also come to understand bootstrapping. -- Regards, John Byrns Surf my web pages at, http://fmamradios.com/ |
#6
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
On Dec 1, 1:29*am, John Byrns wrote:
In article , *Andre Jute wrote: Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. I disagree with you that bootstrap topologies belong in this group. *Bootstrap topologies were and are the darling of commercial makers because they permit the construction of amplifiers with a lower cost. Eh? When I mentioned bootstrap technologies, I had in mind the SRPP, which Japanese ultrafidelista kept alive all those years, a circuit for half a century so obscure that it isn't even in the RDH and is called something else in Vacuum Tube Amplifiers. How can a two-tube stage be more economical than a single tube? First I don't remember saying anything about numbers of tubes, just lower cost. I don't know the relative costs back in the day of tubes, transformers, caps, resistors and pots, but I don't find it difficult at all to imagine some obsessed engineer sitting at his drawing board when he should be playing with his children, trying to eliminate all the caps in an entire amp. (The exemplary Steve Bench actually published such a schematic a few years ago, just for a laugh.) Bootstrap topologies were/are often used in both tube and solid state circuits to increase the voltage output capability of an amplifier stage without resorting to the extra expense of an additional higher voltage B+ supply for the stage in question. * Aha! That is not a reason recognized by the ultrafidelista who generally believe that "mo' iron is betta iron" and even have a bragging measure to account for the amount of iron in an amp, called the Dunker Factor, which measures kilograms per watt of output, the higher the better. For an example of bootstrapping in a tube amplifier, check out the push-pull voltage amplifier stage, the stage following the phase inverter, in the classic McIntosh Mc30 amplifier. *Your homework assignment is to study the voltage amplifier stage of this amplifier, understand how it works, and then explain it to the class so that those less gifted than you may also come to understand bootstrapping. Okay, you caught, me out, I was applying tunnel vision. If I'd known this was going to be a thesis standard interrogation... The CFB via the extra winding, intended to decrease distortion, also results in a very high drive requirement. The answer is found in positive feedback on an earlier stage. Crowhurst showed an analysis somewhere but I don't have time to search for it now. Regards, John Byrns Surf my web pages at, *http://fmamradios.com/ Another question this schemo throws up, if I have it right: Is the output stage operated on such low idle currents that we're looking at something near Class B output? Andre Jute Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ "wonderfully well written and reasoned information for the tube audio constructor" John Broskie TubeCAD & GlassWare "an unbelievably comprehensive web site containing vital gems of wisdom" Stuart Perry Hi-Fi News & Record Review |
#7
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
On Dec 1, 4:42*am, flipper wrote:
On Sun, 30 Nov 2008 19:29:19 -0600, John Byrns wrote: In article , Andre Jute wrote: On Nov 30, 4:17*pm, John Byrns wrote: In article , *Andre Jute wrote: Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. I disagree with you that bootstrap topologies belong in this group. *Bootstrap topologies were and are the darling of commercial makers because they permit the construction of amplifiers with a lower cost. Eh? When I mentioned bootstrap technologies, I had in mind the SRPP, which Japanese ultrafidelista kept alive all those years, a circuit for half a century so obscure that it isn't even in the RDH and is called something else in Vacuum Tube Amplifiers. How can a two-tube stage be more economical than a single tube? First I don't remember saying anything about numbers of tubes, just lower cost. Bootstrap topologies were/are often used in both tube and solid state circuits to increase the voltage output capability of an amplifier stage without resorting to the extra expense of an additional higher voltage B+ supply for the stage in question. *For an example of bootstrapping in a tube amplifier, check out the push-pull voltage amplifier stage, the stage following the phase inverter, in the classic McIntosh Mc30 amplifier. *Your homework assignment is to study the voltage amplifier stage of this amplifier, understand how it works, and then explain it to the class so that those less gifted than you may also come to understand bootstrapping. Another form of bootstrap is to increase impedance. You know, reducing complexity and cost isn't necessarily a 'bad thing' and can be the result of creativity vs brute force. True. It is just sometimes a bit difficult to explain to the ultrafidelista that in audio electronics creativity too must answer to the laws of physics. And those among them who consider taste a license for "personal EQ" simply betray the legacy of Messrs Gilbert and Walker, and their American equivalents. Brute force in SE amps is an expensive waste. You spend 1000% more and get 1% better sound: the economic law of marginality run riot. The 300B is so popular because it is a good compromise between the 2A3 class, which requires huge speakers, and the kilovolt class like the superb 845 which is expensive and hot and dangerous. Andre Jute Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ "wonderfully well written and reasoned information for the tube audio constructor" John Broskie TubeCAD & GlassWare "an unbelievably comprehensive web site containing vital gems of wisdom" Stuart Perry Hi-Fi News & Record Review |
#8
Posted to rec.audio.tubes
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All hail to the ultrafidelista for what they got right
Andre Jute wrote: On Dec 1, 1:29 am, John Byrns wrote: In article , Andre Jute wrote: Among the gifts of the ultrafidelista are the reliance on triodes, on single-ended operation, on Class A1 operation, the clever use of power tubes as drivers, the survival of bootstrap topologies, choke loads on everything, the reintroduction of CCS to audio circuits, and much, much more that the commercial makers would never have brought back, or permitted, without the small but fierce market the DIY ultrafidelista created. I disagree with you that bootstrap topologies belong in this group. Bootstrap topologies were and are the darling of commercial makers because they permit the construction of amplifiers with a lower cost. Eh? When I mentioned bootstrap technologies, I had in mind the SRPP, which Japanese ultrafidelista kept alive all those years, a circuit for half a century so obscure that it isn't even in the RDH and is called something else in Vacuum Tube Amplifiers. How can a two-tube stage be more economical than a single tube? First I don't remember saying anything about numbers of tubes, just lower cost. I don't know the relative costs back in the day of tubes, transformers, caps, resistors and pots, but I don't find it difficult at all to imagine some obsessed engineer sitting at his drawing board when he should be playing with his children, trying to eliminate all the caps in an entire amp. (The exemplary Steve Bench actually published such a schematic a few years ago, just for a laugh.) Bootstrap topologies were/are often used in both tube and solid state circuits to increase the voltage output capability of an amplifier stage without resorting to the extra expense of an additional higher voltage B+ supply for the stage in question. Aha! That is not a reason recognized by the ultrafidelista who generally believe that "mo' iron is betta iron" and even have a bragging measure to account for the amount of iron in an amp, called the Dunker Factor, which measures kilograms per watt of output, the higher the better. "Mo'iron" can make for better hi-fi but only if you know what your'e doing. But the pounds per watt for the best hi-fi is spoken about in the RDH4 pages about OPT construction. Hardly anyone took the RDH4 message seriously. Many amp making companies have for years tried to foist upon the public a bunch of miserable examples of bean counting in the form of lightweight under-performing transformers in all sorts of gear. There is somewhat more to transformers than just the weight. For an example of bootstrapping in a tube amplifier, check out the push-pull voltage amplifier stage, the stage following the phase inverter, in the classic McIntosh Mc30 amplifier. Your homework assignment is to study the voltage amplifier stage of this amplifier, understand how it works, and then explain it to the class so that those less gifted than you may also come to understand bootstrapping. Okay, you caught, me out, I was applying tunnel vision. If I'd known this was going to be a thesis standard interrogation... Bootstrapping sort of works in McI amps. But only because the triodes in the final gain stage LTP have low Ra and this prevents the positive feedback fed back via the bootstrap anode load resistors to have much effect. I've built SE amps needing over 100Vrms drive to output tube grids and its child's play to get less than 1.5% 2H from a pair of EL84 in triode fed dc from a 60H choke plus 10k resistor, and cap coupled to the output stage with normal 1uF and 50k biasing R. McI could have used a scheme like my balanced LTP with ungapped choke and R dc loads and two EL84, but of course they wouldn't, because their way was/is cheaper. In my 300W amps I now use 20% CFB in the output stage via a sample of the Acoustical circuit. I need about 150Vrms grid to grid to drive the amp to clipping. Driver stage THD is extremely low and much lower than output stage distortion so hardly any global NFB is needed. Just enough to lower the Rout of the amp a bit more than when GNFB isn't used. No bootsrapping is used anywhere. I could use it easily, but I have not. I'm not sure if a huge sonic degradation would occur if I did utlilise bootstrapping, or even mild PFB, rather than build the driver stage so it does not need bootstrapping because its so darn linear and had heaps of voltage headroom. In preamps, I do like the boostrapped follower known now as the µ-follower. Measures well and sounds great. Patrick Turner. The CFB via the extra winding, intended to decrease distortion, also results in a very high drive requirement. The answer is found in positive feedback on an earlier stage. Crowhurst showed an analysis somewhere but I don't have time to search for it now. Regards, John Byrns Surf my web pages at, http://fmamradios.com/ Another question this schemo throws up, if I have it right: Is the output stage operated on such low idle currents that we're looking at something near Class B output? Andre Jute Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ "wonderfully well written and reasoned information for the tube audio constructor" John Broskie TubeCAD & GlassWare "an unbelievably comprehensive web site containing vital gems of wisdom" Stuart Perry Hi-Fi News & Record Review |
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