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#1
Posted to rec.audio.tubes
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Fantasy tube
If you were promised that your dream tube would be made at a
reasonable price, if only you can describe it adequately, what would you ask for? Clearly, whatever you specify must not breach the laws of physics, such as asking for a tube giving a hundred watts in Class A for a year on a single AA battery. Andre Jute A little inaccuracy sometimes saves tons of explanation. --H.H.Munro ("Saki")(1870-1916) 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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Fantasy tube
In article .com,
Andre Jute wrote: If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? How about a nice indirectly heated power triode with an anode dissipation limit of 50 Watts, transconductance of 10 mmhos, and a mu of 5. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#3
Posted to rec.audio.tubes
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Fantasy tube
On Aug 13, 10:42 am, John Byrns wrote:
In article .com, Andre Jute wrote: If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? How about a nice indirectly heated power triode with an anode dissipation limit of 50 Watts, transconductance of 10 mmhos, and a mu of 5. You want a triode built around a KT88 plate structure and envelope. I'd say a triode also, but with a direct filament, or better yet two for series or parallel operation, with a somewhat higher plate rating and a little higher mu. Something in between a 300B and a 211. |
#4
Posted to rec.audio.tubes
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Fantasy tube
Brand new Sylvania 8417's for $5 each
"Andre Jute" wrote in message oups.com... If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? Clearly, whatever you specify must not breach the laws of physics, such as asking for a tube giving a hundred watts in Class A for a year on a single AA battery. Andre Jute A little inaccuracy sometimes saves tons of explanation. --H.H.Munro ("Saki")(1870-1916) 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 |
#5
Posted to rec.audio.tubes
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Fantasy tube
On Tue, 14 Aug 2007 02:51:59 GMT, "maxhifi" wrote:
Brand new Sylvania 8417's for $5 each No problemo. I've got a catalog somewhere around here with matched pairs of Genelex KT88's for $12.00. Just jump in Mister Peabody's WABAC machine and grab a couple of whatever ails ya. And, would you grab me a coupla KT66's, just for souvenirs, doncha know? Thanks, as always, Chris Hornbeck "It's just this little Chromium Switch. You people are SO superstitious." |
#6
Posted to rec.audio.tubes
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Fantasy tube
On Mon, 13 Aug 2007 07:35:40 -0700, Andre Jute
wrote: If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? Clearly, whatever you specify must not breach the laws of physics, such as asking for a tube giving a hundred watts in Class A for a year on a single AA battery. A pretty broad, but still very interesting question. Small signal and medium signal tubes are already pretty great, so the hunt must go to output tubes. Linearity and long service life favor a pretty primitive tube family (1000 volts, thoriated tungsten filaments, the whole 1930's shtick) but there is one exception. The WE type 300 managed, by sheer will power, to run linearly and well at 500 volts on oxide-coated filaments. So, my fantasy tube would be a type 300, but WITH A SEPARATE ****ING CATHODE! Is that so ****ing hard to do? Jeez. I'm better now. Thanks for the opportunity to vent. Sorry... sorry... And, thanks as always, Chris Hornbeck "It's just this little Chromium Switch. You people are SO superstitious." |
#7
Posted to rec.audio.tubes
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Fantasy tube
"Chris Hornbeck" wrote in message ... On Mon, 13 Aug 2007 07:35:40 -0700, Andre Jute wrote: If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? Clearly, whatever you specify must not breach the laws of physics, such as asking for a tube giving a hundred watts in Class A for a year on a single AA battery. A pretty broad, but still very interesting question. Small signal and medium signal tubes are already pretty great, so the hunt must go to output tubes. Linearity and long service life favor a pretty primitive tube family (1000 volts, thoriated tungsten filaments, the whole 1930's shtick) but there is one exception. The WE type 300 managed, by sheer will power, to run linearly and well at 500 volts on oxide-coated filaments. So, my fantasy tube would be a type 300, but WITH A SEPARATE ****ING CATHODE! Is that so ****ing hard to do? Jeez. How about a matched pair of 6L6GC's in a compactron envelope, made large to resemble a 300B... or better yet a matched pair of 6L6's, and a 6SL7 in one envelope, with a new, 20 pin base. Guitar amps would never be cheaper to make, and you'd only have one tube to change (ok maybe it would need another 12ax7 or something, but could have a one tube power amp!) Or technically speaking, if someone could make a very linear beam power tube, with a 50W anode dissapation limit, which has such a high gain it only requires 3V of drive to achieve full power, but stable, and not prone to 'meltdown'. Then you could heap on the local NFB and have a nice low output impedance, without worrying about your driver having to swing a huge voltage. (8417 was the best in this category, so far as I know!) Or... a linear triode with a huge flat cathode, large enough to handle several amps, designed especially for OTL amplifiers. This could be in a new envelope style, with a specially designed base. No need to make it octal and glass, or to look anything like the tubes we're used to. How about a microscopic sized planar tube, made on a nano scale, with some new method of etching the grids photographically, rather than winding them. It could be in a little metal case, like a crystal. Maybe even make it surface mount, and overbuilt and derated so it would never need to be replaced. It could be attached to a heat sink like a transistor if you needed more power, and for the really powerful ones, the anode could be the inside of the case. Then you could buy a cell phone with a tube output stage |
#8
Posted to rec.audio.tubes
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Fantasy tube
On Tue, 14 Aug 2007 04:18:28 GMT, "maxhifi" wrote:
How about a matched pair of 6L6GC's in a compactron envelope, made large to resemble a 300B... or better yet a matched pair of 6L6's, and a 6SL7 in one envelope, with a new, 20 pin base. Guitar amps would never be cheaper to make, and you'd only have one tube to change (ok maybe it would need another 12ax7 or something, but could have a one tube power amp!) Could be done, but nobody would buy 'em. Everybody's already got guitar amps; nobody has a personal MIG fighter plane; like that. But, Arf! Or technically speaking, if someone could make a very linear beam power tube, with a 50W anode dissapation limit, which has such a high gain it only requires 3V of drive to achieve full power, but stable, and not prone to 'meltdown'. Then you could heap on the local NFB and have a nice low output impedance, without worrying about your driver having to swing a huge voltage. (8417 was the best in this category, so far as I know!) Transconductance is the natural enemy of cathode poisoning. These tend to devolve into issues of material purity - not a good subject to broach "in these days of modern times". Vacuum valve manufacture is no less complex now than it was in the Kennedy era; the difference now is that nobody cares. Or... a linear triode with a huge flat cathode, large enough to handle several amps, designed especially for OTL amplifiers. This could be in a new envelope style, with a specially designed base. No need to make it octal and glass, or to look anything like the tubes we're used to. That's a Russian type 6336. Get 'em while they're hot. No magic of design can do more than that within design constraints. How about a microscopic sized planar tube, made on a nano scale, with some new method of etching the grids photographically, rather than winding them. It could be in a little metal case, like a crystal. Maybe even make it surface mount, and overbuilt and derated so it would never need to be replaced. It could be attached to a heat sink like a transistor if you needed more power, and for the really powerful ones, the anode could be the inside of the case. Then you could buy a cell phone with a tube output stage Stranger than fiction, something like this might actually happen. Hot cathode emission has only been used in easily-visible-size valves to date, but maybe that's just a failure of imagination (and manufacturing capability, a temporary thing). There are technical advantages to vacuum valves over roughly similar silicon wafer valves (parasitic capacitance, for example), so the future is still undefined. And, let's all give Thanks for that. I think. No, I hope. No, I wish. No, I'm really glad. But anyway, thanks, as always, Chris Hornbeck "It's just this little Chromium Switch. You people are SO superstitious." |
#9
Posted to rec.audio.tubes
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Fantasy tube
Could be done, but nobody would buy 'em. Everybody's already
got guitar amps; nobody has a personal MIG fighter plane; like that. But, Arf! Never know, if one of the big amp companies could get Guitar Player to convince people it's a good idea, and then get some big names behind the amp line, they could sell some. There's no shortage of baby boomers who want to play the blues. All the same, I agree, it's likely cheaper to stick with what's already there. Plus, I admit, it's kind of a boring fantasy tube, because it dosen't really improve on anything, just re-package it, and possibly make it cheaper, although less flexible. Transconductance is the natural enemy of cathode poisoning. These tend to devolve into issues of material purity - not a good subject to broach "in these days of modern times". Vacuum valve manufacture is no less complex now than it was in the Kennedy era; the difference now is that nobody cares. Yes, but that's what makes it a fantasy tube... it dosen't break any laws of physics, but similar to other fantasies, such as having a fulfilling marriage to a supermodel, it's not meant to be. All the same, tubes like 8417 and 7591A came close, and if developed further, could result in something. For example, could frame grid technology a la 6DJ8 be applied to an output tube? That's a Russian type 6336. Get 'em while they're hot. No magic of design can do more than that within design constraints. I think the 6336 is a US tube - a super regulator dual triode which looks like a KT88 - you mean the 6C33 or whatever it's called. I saw some of those recently - really impressive and strange looking beasts! All the same, they were not originally designed as OTL output tubes, and I'm sure they could be improved upon if it was an application specific design, from the ground up. My guess is if you gave a several million dollar grant to say, atma-sphere, and, say, JJ, or svetlana to work together to come up with the ultimate OTL tube, something better than the 6C33 or 6AS7 would result. Stranger than fiction, something like this might actually happen. Hot cathode emission has only been used in easily-visible-size valves to date, but maybe that's just a failure of imagination (and manufacturing capability, a temporary thing). I wonder if there really is a technical reason for this. Is there a physical limit to how small a hot cathode tube can be, and still work? I am sure there would be huge challenges to overcome, but if solved, it could be interesting. |
#10
Posted to rec.audio.tubes
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Fantasy tube
On Aug 13, 11:23 pm, Chris Hornbeck
wrote: On Mon, 13 Aug 2007 07:35:40 -0700, Andre Jute wrote: If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? Clearly, whatever you specify must not breach the laws of physics, such as asking for a tube giving a hundred watts in Class A for a year on a single AA battery. A pretty broad, but still very interesting question. Small signal and medium signal tubes are already pretty great, so the hunt must go to output tubes. Linearity and long service life favor a pretty primitive tube family (1000 volts, thoriated tungsten filaments, the whole 1930's shtick) but there is one exception. The WE type 300 managed, by sheer will power, to run linearly and well at 500 volts on oxide-coated filaments. So, my fantasy tube would be a type 300, but WITH A SEPARATE ****ING CATHODE! Is that so ****ing hard to do? Jeez. I'm better now. Thanks for the opportunity to vent. Sorry... sorry... And, thanks as always, Chris Hornbeck "It's just this little Chromium Switch. You people are SO superstitious." Oh, I dunno... The KT88/6550 and KT90 are pretty good tubes given that I have no predilections towards SE devices. My fantasy tube would be new-production small-signal tubes along the lines of the Sylvania Mil.Spec. series with the 5751 being the best of that. Very low noise, low microphonics, great longevity.... So, make of that quality, but include the various 6XX and 12XX tubes, miniature and octal as needed. Of, course were I to be having a Jutean Fantasy, I would extend that wish-for-quality to extend to power-tubes as well. Never happen. Peter Wieck Wyncote, PA |
#11
Posted to rec.audio.tubes
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Fantasy tube
Hi RATs!
It probably already exists. My fantasy is I will get it into a friendly circuit before I pop my filament. I put new JJ E88CC in the first stage of Ella and the EL34 sounds really great. Happy Ears! Al |
#12
Posted to rec.audio.tubes
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Fantasy tube
tubegarden wrote:
Hi RATs! It probably already exists. It is human nature to think the glass is half-empty when in fact it is two-thirds full. -- Andre Jute My fantasy is I will get it into a friendly circuit before I pop my filament. I put new JJ E88CC in the first stage of Ella and the EL34 sounds really great. Happy Ears! Al |
#13
Posted to rec.audio.tubes
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Fantasy tube
Andre Jute wrote:
If you were promised that your dream tube would be made at a reasonable price, if only you can describe it adequately, what would you ask for? Clearly, whatever you specify must not breach the laws of physics, such as asking for a tube giving a hundred watts in Class A for a year on a single AA battery. I deliberately didn't specify my own idea to start with so that everyone else could have all the court to shoot from. But it is amazing how alike we all think, at least as long as we stay inside the envelope; in fact it will look like I took my idea from John, from Ronnie, from Chris and from Max! My idea is a twin triode in an octal base glass tube the shape of and no larger than a 300B, working off a real life (not max) B+ of 385V and requiring no more than 60V of signal for full output, which should be in the order of 10W per side (real output at everyday parameters, not theoretical output at Pdmax; a WE300B is effectively a 6W SE tube in real life, not the 10W American ponycar amp makers claim). Indirectly heated filaments might be nice but I don't consider them as essential as John does; DH fils have never bothered me much. I don't care how hot the tube gets if the longevity is reasonable. It seems to me that the 300B/845/211, that entire lot, are tubes whose performance is depressed in favour of longevity; I have WE300B getting on for 20K hours, at least, an entirely unreasonable life expectancy, in effect indestructable in conservative designs. Two tubes in the same envelope so it can be PSE or PP. Octal for cost. 10W per side so that 20W is easily achieved in PSE or more in PP up to much more with variation among output classes. 385V is chosen for component cost; it fits into the standard cap for 230V mains, so the any iso-transformer will do, and the caps are cheap too. 60V signal is easily achieved with a single or at most two stages of voltage amplification. I'd also specify a second tube as a driver: two 417A in the same envelope, which can be bigger than the child's thumb of the present 417A, say up to 6SN7 size. (Actually, I'd ask for two 437A in the same envelope, and settle for the two 417A if the man said 437A are impossible. A 417A is good up to 24mA and has a mu of over 40; a 437A is a 417A on a lifelong diet of steroids.) The reason for asking for 20mA and over is because that is what is necessary on a driver to overcome Miller in PSE 300B or single 845, which have approximately the same parameters I specify above. Or, if I can't have any of that, how about 4x 6SN7 in one envelope, or 2x 6SL7 + 2x 6SN7? But these are just convenience matters (except for the unobtainable 437A); as Chris says, small signal and driver tubes are probably a done deal, at a peak of perfection. And, since I would have the guy pinned down, still trying to close his mouth, I'd impress on him the necessity of a new rectifier, twin GZ37 in one tube, i.e. a complete one-tube high voltage high current bridge rectifier). The reason I don't choose the venerated GZ34 is that the -37 is a better rectifier in every respect and anyway its size and shape match the 300B bulb I've already specified above. All that heat may need the bigger tube too than the GZ34. The reason for asking for a kilovolt tube bridge rectifier is many a slip twixt the cup and the lip: the new tubes may turn out to be rubbish and then we shall all want to go back to 845... 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 |
#14
Posted to rec.audio.tubes
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Fantasy tube
In article om,
Andre Jute wrote: And, since I would have the guy pinned down, still trying to close his mouth, I'd impress on him the necessity of a new rectifier, twin GZ37 in one tube, i.e. a complete one-tube high voltage high current bridge rectifier). The reason I don't choose the venerated GZ34 is that the -37 is a better rectifier in every respect and anyway its size and shape match the 300B bulb I've already specified above. All that heat may need the bigger tube too than the GZ34. Wouldn't it take something more like a triple GZ37 to make "a complete one-tube high voltage high current bridge rectifier"? At least three independent cathodes would be required, along with three rectifier heater windings on the Power Transformer. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#15
Posted to rec.audio.tubes
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Fantasy tube
Wouldn't it take something more like a triple GZ37 to make "a complete
one-tube high voltage high current bridge rectifier"? I think he means one complete GZ37, and then another complete one with independent cathode connections. At least three independent cathodes would be required, along with three rectifier heater windings on the Power Transformer. Not if the heater/cathode insulation is up to the task. If the EZ81 can handle it, so can this super tube! Make it a 6.3V heater, too. |
#16
Posted to rec.audio.tubes
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Fantasy tube
William of Occam suggests that it is dangerous to multiply entities
needlessly. So, in striving for the "Perfect Tube", it would be my contention that overly complex tubes, and/or tubes required to serve too many purposes become dangerously complex with a logarithmic propensity towards error/failure. I deliberately didn't specify my own idea to start with so that everyone else could have all the court to shoot from. But it is amazing how alike we all think, at least as long as we stay inside the envelope; in fact it will look like I took my idea from John, from Ronnie, from Chris and from Max! My idea is a twin triode in an octal base glass tube the shape of and no larger than a 300B, working off a real life (not max) B+ of 385V and requiring no more than 60V of signal for full output, which should be in the order of 10W per side (real output at everyday parameters, not theoretical output at Pdmax; a WE300B is effectively a 6W SE tube in real life, not the 10W American ponycar amp makers claim). Indirectly heated filaments might be nice but I don't consider them as essential as John does; DH fils have never bothered me much. I don't care how hot the tube gets if the longevity is reasonable. It seems to me that the 300B/845/211, that entire lot, are tubes whose performance is depressed in favour of longevity; I have WE300B getting on for 20K hours, at least, an entirely unreasonable life expectancy, in effect indestructable in conservative designs. A 300B on steroids may be a good idea, save that it leads to the necessary admission that SE designs have inherent limitations in headroom that could be solved with a "Bigger Tube".... this leads to the inevitable Americanism: When all else fails, get a bigger hammer. The last 80 years of tube design have generally shown that after flea- power comes PP, and that PP systems may be (to use Mr. Turner's word) "blameless" with good design. Two tubes in the same envelope so it can be PSE or PP. Octal for cost. 10W per side so that 20W is easily achieved in PSE or more in PP up to much more with variation among output classes. 385V is chosen for component cost; it fits into the standard cap for 230V mains, so the any iso-transformer will do, and the caps are cheap too. 60V signal is easily achieved with a single or at most two stages of voltage amplification. Now, here is where the laws of physics-on-the-cheap get nudged. Heat dissipation is a function of design, envelope size (exposure) and other mechanical factors. This would necessarily be a fairly large tube, on the order of some of the more significant transmitter tubes and therefore something of a real-estate hog. Furthermore, that sort of power-handling would also require the perfect socket with perfect contact surfaces. So far, though, well within good science and (quite- costly) available technology. But price would definitely be an object. And again, putting both in the same envelope does considerably multiply entities, especially in a power-tube. Advantages: the presumption that both sections age equally and together. Disadvantages: The entire tube becomes useless should that not be so. I'd also specify a second tube as a driver: two 417A in the same envelope, which can be bigger than the child's thumb of the present 417A, say up to 6SN7 size. (Actually, I'd ask for two 437A in the same envelope, and settle for the two 417A if the man said 437A are impossible. A 417A is good up to 24mA and has a mu of over 40; a 437A is a 417A on a lifelong diet of steroids.) The reason for asking for 20mA and over is because that is what is necessary on a driver to overcome Miller in PSE 300B or single 845, which have approximately the same parameters I specify above. Or, if I can't have any of that, how about 4x 6SN7 in one envelope, or 2x 6SL7 + 2x 6SN7? But these are just convenience matters (except for the unobtainable 437A); as Chris says, small signal and driver tubes are probably a done deal, at a peak of perfection. And, since I would have the guy pinned down, still trying to close his mouth, I'd impress on him the necessity of a new rectifier, twin GZ37 in one tube, i.e. a complete one-tube high voltage high current bridge rectifier). The reason I don't choose the venerated GZ34 is that the -37 is a better rectifier in every respect and anyway its size and shape match the 300B bulb I've already specified above. All that heat may need the bigger tube too than the GZ34. The reason for asking for a kilovolt tube bridge rectifier is many a slip twixt the cup and the lip: the new tubes may turn out to be rubbish and then we shall all want to go back to 845... Mpfffff.... OK.... being a crude American, a heavy duty rectifier is hard enough these days, putting two of them in the same envelope gets quite close to the physical limitations of the beast... and three (or more) to make the full bridge becomes needlessly complex. As to the 417a et.al., I would take a lesson from the venerable7199, a tube that brackets the extremes of excellence and failure, with the general propensity towards the latter end of the spectrum. In the words of George Santyana: "Those who do not remember the past are condemned to repeat it." I happen to very much like the 7199, when I have a dozen available to find two or three good ones. But for that reason, I am staying away from it and that general philosophy with my homebrew. I have my stock of very good 7199s, but it took me some years and a few dozen examples to find my six working pairs and six spares. I would strive for refinement of existing tube designs, or as the KT90 is an evolutionary improvement to the KT88, strive in those directions. Tube design has been "perfect" for about 40 years now in terms of genuine and actual new designs or approaches. Packaging differences lead to a false sense of simplicity with greater complexity in the design with little potential for real improvement. Much as chips offer the same sorts of pitfalls and pratfalls as compared to discrete components... Lest anyone think I am being a luddite, not hardly. Cell Phones have the functional equivalent of a trainload of discrete components, no argument there. But power amplifiers are not cell phones and overly complicated multi-function tubes are called Compactrons last I looked. And, we must all remember, WE was an entity of the Bell System, concerned with reliable telephone service, movie recording and sound systems and other broad-brush applications where reliability and simplicity and longevity and ease of service were driving factors with 'fidelity' being an almost accidental by-product. So their tubes were to that end and adapted to home audio systems only as latter-day adaptations. The bandwidth of a 1950s land line was no better than the typical single-driver horn speaker, so not much was needed of the electronics other than reliabilty. Similarly all but a very few movie houses used a couple of massive horn speakers (woofer & tweeter), with not much expected there either other than within the voice spectrum. Give me the functional equivalent of a Sylvania Mil.Spec. 5751 at all levels of the tube spectrum, and I will be a very happy camper. In general, I am easily pleased. It need only sound good. Looks, cost, and yiches notwithstanding. That tube is a very fine combination of price, function, ruggedness and longevity. Would they were all so... THAT is my fantasy. To each his own. This is a fantasy throughout, so we are all entitled to our own without limit. Peter Wieck Wyncote, PA |
#17
Posted to rec.audio.tubes
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Fantasy tube
On Aug 14, 4:43 pm, John Byrns wrote:
In article om, Andre Jute wrote: And, since I would have the guy pinned down, still trying to close his mouth, I'd impress on him the necessity of a new rectifier, twin GZ37 in one tube, i.e. a complete one-tube high voltage high current bridge rectifier). The reason I don't choose the venerated GZ34 is that the -37 is a better rectifier in every respect and anyway its size and shape match the 300B bulb I've already specified above. All that heat may need the bigger tube too than the GZ34. Wouldn't it take something more like a triple GZ37 to make "a complete one-tube high voltage high current bridge rectifier"? At least three independent cathodes would be required, along with three rectifier heater windings on the Power Transformer. Yes, you're right. This was pointed out to me by Mr Williamson, my correspondence tube electronics tutor with whom I had been studying Kondo's Ongaku, when I just naturally put four GZ37 on my first kilovolt supply. But a decade and more has passed since then, and I still use four full wave GZ37 per bridge (God bless Billington for supply, and for 5R4GWY -- the ones with ceramic bowl base -- that actually do the HV business unlike some probably Russian-made rubbish I also had) and my trannies have four filament supplies... I just forgot. But even if we take up Max's idea, of a second GZ37 in the same envelope with an independent filament for each plate, that's too many connectors to fit into my other parameter of a standard octal base. (Four plates and 6 filament/cathode connectors add up to 10.) I'll have to amend that to a GZ37 with separate cathodes/fils per plate separately brought out. Still, that's only two tubes for a bridge, rather than three, so there's a saving of one tube, and other convenience too. (Though, on the whole, I am not impressed with crosstalk through the filaments, which once exercised the obsessives on the Joenet. I remember mentioning it to Simon S, the British amp and tranny designer, and he burst out laughing.) Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ Thanks for bringing Mr Williamson to my mind. I haven't thought of him recently, and he deserves to be remembered for everything he taught me. Andre Jute Now let us praise famous men -- Ecclesiastes 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 |
#18
Posted to rec.audio.tubes
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Fantasy tube
In article .com,
Andre Jute wrote: But even if we take up Max's idea, of a second GZ37 in the same envelope with an independent filament for each plate, that's too many connectors to fit into my other parameter of a standard octal base. (Four plates and 6 filament/cathode connectors add up to 10.) The triple cathode scheme I suggested requires only 7 pins, so it would easily fit an octal socket, although the creepage distance might not be enough for a kilovolt supply. Perhaps one of those ceramic bowl bases like the 5R4GWY has, along with a ceramic socket, might make it workable. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#19
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Fantasy tube
On Aug 16, 6:19 pm, Bret Ludwig wrote:
Don't say I said so, but as close as is going to exist to what Andrew wants already does: it's a 3C33. Spec sheet with curves here. http://frank.yueksel.org/sheets31.html Very nice indeed. Offered for sale elsewhere for USD75 each, doesn't say how many the dealer has or what prospect of replacement... Sockets by Johnson still in production, offered yet another place for USD45 each. Makes 845 look cheap. At these prices it may be worth trying a little SE amp for those desperate for a new thrill. At least it is a tube with a different, interesting shape. Andre Jute That same socket is what YOU want, except, you don't. If you really wanted a tube rectifier-and if sound and not EMP resistance is the goal, you really do not-what you want is not a vacuum type but a xenon gas type. Refer to the GEC manual. The mercury vapor type is also good if you are willing to put it in a cage and put RF chokes in, but I doubt any tube plant will make them for you. I would not bother making a new vacuum rectifier type for the simple reason that if someone is hellbent on vacuum rectification they can always use a strapped triode. |
#20
Posted to rec.audio.tubes
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Fantasy tube
On Aug 14, 8:25 pm, John Byrns wrote:
In article .com, Andre Jute wrote: But even if we take up Max's idea, of a second GZ37 in the same envelope with an independent filament for each plate, that's too many connectors to fit into my other parameter of a standard octal base. (Four plates and 6 filament/cathode connectors add up to 10.) The triple cathode scheme I suggested requires only 7 pins, so it would easily fit an octal socket, although the creepage distance might not be enough for a kilovolt supply. Perhaps one of those ceramic bowl bases like the 5R4GWY has, along with a ceramic socket, might make it workable. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ Mmm. I had something in mind in which the rectifieers may serve as a bridge, or be used separately, for instance as in my Modular Series 300B Lundahl where I merely fullwave rectified two separate lines. But I think this rectifier idea of mine, a throwaway at the end, is the most troublesome of all the ideas floated by anyone yet. How high is an octal socket supposed to be rated? I used to have a Tannoy amp that put 864V into an octal socket and I'm sure they wouldn't have done so if the socket was not rated for it. And, while we're on sockets, one of the reason I like the octal is that it is reasonably well insulated from the top. A UX4 for a 300B or a Jumbo 4-pin for an 845 is lethal when the tube is not in it. 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 |
#21
Posted to rec.audio.tubes
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Fantasy tube
I put new JJ E88CC in the first stage of Ella and the EL34 sounds
really great. Happy Ears! .... days later ... the new tubes are teaching the entire system and room how to Play Music. .... I may even become a better listener, if not more exciting typist. The new IP connection tests at 2475m/750m. I would like to post videos of how to treat tubes to a fun life ... but, at the speed I type, I would be dead before I finish heater principles. Anybody ready for video NG for empty heads on tube post recreationistas? Al |
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