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Output Tubes

mikeski

mikeski

I need input
Hi All, I been wrenchin on a few amps lately. All have been different output tubes. EL34, 6V6 & 6BQ5. I know there are others out there to play with also.
It's just to much scratch to stock up on all the different tubes. A quad of Tele EL34's just went for $700 on the bay. I can't roll tubes like that let alone try to do it across many types.

So, if you had to pick two output tube's to concentrate on what would they be????
 
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jaymanaa said:
6bq5
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I'm with him... although I'd probably add 2A3!

I have yet to hear a bad sounding amp using the 6BQ5/EL84 - single-ended or push-pull; pentode or triode, Williamson or U/L...
The Russian "6p15p-ev" (6П15П-EВ in Cyrillic) tube is very nice sounding, inexpensive, and robust.

FWIW: I have several 7591 amps and receivers around here... I am still not totally sold on 'em... I've been told that there were some HH Scott power amps that used 7591s that are superb... but I've not experienced any of those to date.
 
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6L6 and EL84.

The former for power and the latter for sweetness of sound.

Of course it's always fun to experiment with different tubes...
 
Right now I am playing with a number of them to see what I like. I want something that will reach down with out any problem. I am currently not using any tone controls as in none installed. I do like push pull.

I have been running my ST70 in Triode mode. That seems to be plenty to drive my Heresy's.

I have been slipping away from the heavy rock of my youth and sliding into quieter jazz and soft rock. And at lower volumes. So I would like a smooth middle with a detailed base and not to tinny on the top.
 
So far, I'd say 6BQ5 & 6V6. When I first started messing with tubes a few years ago, I had no idea what I was after, so I've made some weird buys & side trips, but that gets pretty darn expensive, like you pointed out. I still have an HK PP 6L6 amp in the basement to refurb, so "could" change my mind. ;)
 
Well, "reach down without any problem" sounds like you should stay away from small power tubes, because OPT losses in the deep bass region often demand higher power to compensate (assuming global feedback). I suggest 6L6GC/5881 and the 6CA7/EL34 family.
 
Ha, with that last post we have now fully covered the three listed in the OP, and I don't see any overwhelming lean towards any two. 'bout what I expected.

BTW, That quad of EL34's that went for $700 must have been something pretty special and rare. You can find quads for under $100, (but probably not Tele's :))
 
What binary Mike said, but more towards the EL34s. The Mullard re-issues sound good to my ears, and a matched set form Jim McShane won't break the bank. It depends a great deal on the speakers you plan to use.
 
EL84/6V6 would be on my short list(I consider them 1 tube type)...

Second tube type for me would be to hard to nail down, as I like to many... :)
(but 7AC pinout tubes are nice to have a variety, as many are interchangeable)
 
6V6's are everywhere and cheap.

Can anyone add experiences with 6AV5 tubes? I have no idea what to do with the Bogen K030 monoblock that I picked up. It has 6AV5's, a high impedence input and a low impedence input with a step-up transformer, and I'm interested in what sounds I may get with it, particularly as a guitar amp.

Any suggestions?

I've read that 6FW5's (I think) are an upgrade from 6AV5's, and are generally an easy conversion.

Any thoughts on either 6AV5's or 6FW5's???
 
mhardy6647 said:
I'm with him... although I'd probably add 2A3!

I have yet to hear a bad sounding amp using the 6BQ5/EL84 - single-ended or push-pull; pentode or triode, Williamson or U/L...
The Russian "6p15p-ev" (6П15П-EВ in Cyrillic) tube is very nice sounding, inexpensive, and robust.

FWIW: I have several 7591 amps and receivers around here... I am still not totally sold on 'em... I've been told that there were some HH Scott power amps that used 7591s that are superb... but I've not experienced any of those to date.
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I wonder if they run them in pure pentode with regulated screens? That's the best I've heard them personally.




6AV5 is a very robust tube that can sound fine.
 
I'd have to throw my lot in with the 6L6 family, for sheer bang-for-the-buck. IMHO, a 6550/KT88 can sound a LITTLE better, but the parts get much more expensive, quick.

A set of 6L6/5881/7581, with a Mullard-topology front end (i.e Eico HF22 or Harman-Kardon Citation V) can be something very special. Bass? You got it. Clean too.

There ain't a whole lot out there, IMHO, that will sound much better than a properly-set-up 6L6 Mullard-circuit amp. Only will get you between 20-40 watts per channel... but oh, what a GOOD sounding 20-40 watts that will be...

Regards,
Gordon.
 
845's rule.
Iconaudiosept2010005.jpg
 
jaymanaa said:
I wonder if they run them in pure pentode with regulated screens? That's the best I've heard them personally.




6AV5 is a very robust tube that can sound fine.
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I dunno - I do know that every time, at local get-togethers, I bemoan the fact that all the 7591 amps/receivers I have don't quite do it for me, Gary Kaufman says I've gotta listen to one of those Scott power amps. I don't even know the model(s) :-P

(more) on topic: can't say I've ever encountered an amp using the 6AV5.
 
It's actually a sweep tube, but Bogen used it some I think, and tubelab over at DIY has done extensive experimenting with it as an audio tube. It would appear that the tube (at least certain types/brands) can be run well beyond their stated limitations with no harmful effects. They used to be a two dollar tube, but I bet they are more now. Looks to be a 5 dollar tube these days.
 
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