Having studied more schematics than I can count (including those of the 5000-dollar and up amps) and experimented with most all the popular tubes, both preamp and power tubes, and after testing out more preamp designs than I can recall, I can with complete confidence state that an amp built with organ output transformers using the extremely high distortion 6BQ5 is a long way from an amp worth bragging about. The 12AX7 and related tubes are used because they are ubiquitous. A serious audiophile wouldn't touch them with a ten-foot pole. I find it both amusing and sad that there has been practically no innovation in tube amp designs in 60 years. Knowing what I know of tube amp designs, unless you have come up with some remarkable new design in the preamp, I seriously doubt you are getting results much different from stock organ amps. I resorted to designing my own and I don't use 12xx7 tubes. They were tested rigorously and came up very short. In fact, only one Noval tube had good specs. So, if your clients are coming from solid state land to tubes, I can see them being impressed. Otherwise, I have serious doubts. Not sure what the big fuss is with Lance Cochrane. If he was serious, he'd use GOOD tubes and GOOD transformers, not bargain basement parts.
Few tubes were actually made for audio. The tubes in audio amps (with few exceptions) were used in radios, TVs, etc. The KT88 I believe was made for audio. The RCA 7199 (pentode/triode) I believe was also made for audio. IMHO an audiophile tube is one that can be implemented with GOOD results. The 6BQ5 isn't such a tube. The EL34, especially in ultralinear, produces extremely low distortion. Tetrodes, which are found in many audio amps, are actually inferior to true pentodes, and yet they far outnumber pentodes in audio amps. The guy that runs the Fun With Tubes website on Angelfire does some real world testing where he compares the 6L6GC and the EL34 and (this quite surprised me) the EL34 did much better. The EL34 has a rep for having "flabby" bass, yet it bested the 6L6GC in the bass dept!. I (luckily) found inexpensive, powerful, reliable, true pentodes (more power than the KT88) and built an ultralinear amp around them. These tubes were designed for radio, yet were used in audiophile amps and are considered an audiophile grade tube. Even in triode mode, they are rated at 40 watts plate dissipation.
In short, I would say if you get low distortion and reasonable power, I'd call it an audiophile tube. FWIW, i found an article wherein many, many preamp tubes (triodes) were tested for distortion and with one lone exception, octal socket tubes bested the Noval socket tubes. Only one Noval equaled the octals. Yet what tubes do you see used most? The 12xx7 family. Even the expensive amps use the 12xx7 family.
and I just thought the EL84 looked like one of the last and only reliable tubes left, but I guess not 
or it could be the usual, the more you know the worse it gets
or maybe we are just grapping the wrong end of the stick
I probably am, because every time I try to approach tubes I get a funny feeling
or it could be the usual, the more you know the worse it gets
or maybe we are just grapping the wrong end of the stick
I probably am, because every time I try to approach tubes I get a funny feeling
and I just thought the EL84 looked like one of the last and only reliable tubes left, but I guess not
or it could be the usual, the more you know the worse it gets
or maybe we are just grapping the wrong end of the stick
I probably am, because every time I try to approach tubes I get a funny feeling
The data sheets tell the story. They list the distortion specs. My first tube amp was an EL84 stereo push-pull. I was just learning. As soon as I got a 6V6 amp, I sold the EL84, the 6V6 was just way better sounding. Later, I acquired a Heath amp with EL84 tubes. I fixed it and sold it. No regrets about selling either, although the Heath was better sounding, a fact i will attribute to the output transformer's quality. When the third EL84 fell into my lap, I didn't waste any time. I just listed it on ebay and sold it. I realize the EL84 has a loyal following, but I don't get it. The only amps I heard that sounded worse were 6BM8. My GF was in agreement on all of the above. She gave them a big thumbs down when I hooked them up.
And all the early 6V6 data sheets show it to be a beam tetrode (later ones call it a "beam power tube"), not a pentode. How does this fit your world view as outlined in post #666?
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i do not believe in audiophile tubes.....there are only tubes....
and what you do with those tubes is what really matters....
tubes do not have a sound of their own, you still have to plug them in...
tube amps almost always have an output transformer...
now this transformer is the real deal maker, in my book...
and what you do with those tubes is what really matters....
tubes do not have a sound of their own, you still have to plug them in...
tube amps almost always have an output transformer...
now this transformer is the real deal maker, in my book...
I have read this in another thread, , a few weeks ago
and I'm not surpriced
but question is ... which quality 6V6 is needed to achieve that
6V6 can be quite expencive too
It was a generalization, obviously. And not my observation alone. There are people who have more money, much better equipment, and more time than I have who rigorously test tubes and make observations. In this case, the data sheets confirm what my own ears tell me, EL84 is crap. You wouldn't expect a POOR quality pentode to outperform a well-designed and well-made beam tetrode, would you? My own experience as well as the testing done by others backs up the generalization that true pentodes sound better. If you care, I'll see if I can find the relevant literature. If you're just being argumentative, that's great. You can have your beliefs. When I was early on the learning curve, it was extremely difficult as I encountered more falsehood than truth regarding tubes, even from electrical engineers, and simple questions asked of people regarded as masters went unanswered or answered erroneously. So, I look for proof and I take no one individual's word for anything; I Look for corroboration. I have also learned to be extremely skeptical of claims by manufacturers who claim superiority by way of extremely low distortion with tubes, magical sounds with mediocre design and parts, etc. The schematic tells the story. Anyone claiming his amp is head and shoulders above the rest should release the schematic or give it a rest.
IMHO, this is a great tube amp secret. 12 volt heaters are better 'cause it's easy to rectify and filter (make DC), and that reduces hum in many cases. There are 12-volt heater versions of many popular tubes, and the 6V6 is one of them. I bought a goodly number of black plate 12V6 and that is what I have; I don't actually have 6V6 tubes, never did have. The 12-volt heater versions of popular tubes are almost always way cheaper. If you want some good NOS or lightly used 6V6 tubes, look for the Conn organ 12V6 tubes (almost always black plate). They will have "Conn" written on them, but they are almost certainly RCA or Sylvania. Being black plates, I'm guessing RCA. I'm told Sylvania made some of their tubes; I don't know if that's true or not.
ALmost every 12V6 I picked up on ebay dirt cheap tested new or nearly new and about 1/3 tested better than new. They seem to be quite reliable and long-lasting if not driven real hard. I'm sure you are aware that there is absolutely no diff between the 6 and 12-volt versions, other than the heater voltage applied.
Perusal of the Conn schematic will reveal that they were conservative in B+. My first 6V6 was actually a stereo Conn 12V6. It required very little modification for home stereo use. That replaced the RCA EL84 integrated amp I had with new JJ tubes. The Conn was just way better sounding stock.
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"i do not believe in audiophile tubes.....there are only tubes."
IF that's true, then there are a lot of people wasting their time tube-rolling.
IF that's true, then there are a lot of people wasting their time tube-rolling.
I think its common knowledge around here that tube rolling is waste of time because mostly performed by people who know very little about their amps, and thus also 'forgets' to check adjustments etc
isn't that what tube rolling means ... just changing tubes at random ?
but since you are able to test your own tubes it may mean something different you
will check the 12V6, thanks!
but testing and matching used tubes ...
That's interesting. I had a discussion with an EE who made the same claim and also told me I should be using op amps 'cause modern op amps have such superior specs, how could tubes hope to compete with that? I can believe him, or I can believe my ears. I HAD two off-the-shelf op-amp electronic crossovers. Then I built my own using first tubes and then JFETs. I stuck with the JFETs, they sounded better. Had I taken the word of the man with the 4-year degree, I'd be using op amps. Similarly, I have noted people with EE's also claim that the tube's specs tell the whole story. My ears disagree. Apparently a lot of people's ears disagree.
But if you are correct, then there are a lot of people wasting time and money with tube-rolling.
I would say that decent tubes paired with the APPROPRIATE transformer is what makes the diff. IMHO, the output transformer IS more important than which 6L6 you use with it, I still have to believe which tube matters 'cause I have noted MARKED differences between some of the 6L6GCs in the exact same amp. If a tube is just a tube, then nobody should be hearing a diff when they roll
ahh, you dont' seem to understand what AJT was saying
like saying, you cannot judge any kind of tube in amps you don't know in details how they are designed and built
its first when you fully understand the amp design used that you can be able to judge why a certain tube sounds like it does in that amp
like saying, you cannot judge any kind of tube in amps you don't know in details how they are designed and built
its first when you fully understand the amp design used that you can be able to judge why a certain tube sounds like it does in that amp
My bad. I'd have to emphatically agree. Seen some tubes that I had great success with trash-talked and I'm convinced it was because they were not being used right.
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