#4571
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I have GL's and JJ's and prefer the GL. Dennis likes the JJ's. Different systems different preferences. |
#4572
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Bypass capacitors
I bought a couple of Duelund tinned-copper bypass caps and will solder them in the amp and preamp soon. I have not done this before.
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#4573
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There are certainly a lot of tube amps on the market which have this feature.
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#4574
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I too would like to see this option. I imagine there would be some give and take though. Dennis catches me as a purist, putting something in the circuit that might degrade may not sit well with him.
Haveing a pair of those mono’s pumping out 25 watts might come in handy from time to time. It would be nice to have that level of adabtability as we all know a stereo setup is a contantly evolving entity... |
#4575
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#4576
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[IMG][/IMG]
Simon, the Duelund bypass caps are .01uf and physically small. No lift kit needed. The photo is an LP27a, not mine, with .22uf Auricaps paralleled with the Audyn coupling caps and a Jantzen, can't read the value, bypass cap on the electrolytic cap. Last edited by FloridaBoy; 06-14-2018 at 05:56 AM. |
#4577
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This just in from Dennis, apparently he is watching us.... LOL
Dennis wrote: I firmly believe that the option of triode/pentode or triode/ul switching option is market driven. When one truly looks at the huge disparity in plate resistance of a vacuum tube in the pentode, beam power and tetrode configuration vs triode it is amazing. A simple example is the 6L6. The plate resistance in the pentode mode is on the order of 35,000 ohms. The same mighty 6L6 wired in the triode mode the plate resistance is on the order of 1700 ohms. The difference is night and day. The plate resistance of the tube will determine the proper primary impedance and ratios of the output transformer in the tube amplifier. An example of the 6L6 wired pentode would operate properly with a primary impedance of 7000 ohms. Take the same 6L6 wired triode the impedance is now on the order of 4500 ohms. I prefer to use a 4300 ohm primary for the basic beam powered tubes wired as triodes. The ultimate sound quality of a high performance vacuum tube amplifier is so dependent on the proper impedance and ratios of primary to secondary windings of the output transformer. Anyway … I could go on and on . but simply stated … the differences are much too great in the sonic results of a compromised, market driven triode/pentode/ul switch. Give me some time and I could really let you know what I think of the ultra-linear (ul) mode of degenerative negative feedback!!!!!!!! |
#4578
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Dennis Had Inspire Amps
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Been listening to the to the 6f6gs for a day now. Definite keepers. The bass is very strong. Not lacking anywhere as I can tell but this is my work system and I am not doing really critical listening. I have not done it yet but may turn down the subs. I switched out GL kt77s for this change up though this is not my Proac system (Omegas) at the moment. 24 watts to maybe 4-5 watts and I am thinking about turning down the subs. Go figure. Anyway, they are cheep (relatively). Give them a try. Last edited by BearCityUSA; 06-14-2018 at 05:58 PM. |
#4579
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Quote:
Sorry to be so late in responding to your post. I just got back from 18 days abroad. I'm glad you liked my amp. I've purposely been following a little different path than Dennis, but we really benefit from trading ideas and experiences. Mind you, Tony and I are basically his apprentices, and I would never begin to think I could ever come close to his depth of knowledge and experience. How am I ever going to get 50+ years of experience building toob amps?!? But, since I don't know any better, I try stuff just to see if it will stick to the wall, and it gives him an idea, etc. I'm pretty well set for amps currently, although I think a Universal amp of some type is in my future, along with an amp built around the 8417 tube. As an aside, this was the pinnacle of tube development in the 60's and are very hard to find. I happen to have a stash of them for some other amps I've accumulated, and may siphon 2 or 4 off for this project. The KT series of 90 or above are essentially just bigger power versions of the 88s, no matter how much the manufactures will argue. The 8417 is a novel design, once described as a “cavity anode”. Next up on the block is a preamp, perhaps based on the 26 or 01A tube. Yes, Dennis doesn't like these directly heated triodes, but I have a stash of both, and I need another preamp, especially one with a dedicated center channel. Lastly, I have fallen in love with the blue glow of the mercury filled half wave rectifiers. Bought a pair of 816s and they will definitely be going into an amp in the near future... Last edited by Analog Addict; 06-14-2018 at 05:09 PM. |
#4580
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It's official the, the Universal is on the market!!!
Check out Dennis' latest ebay listing. |
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