EL84's What do we like?

[tomteriffic]

My venerable Teefus'ed Classic 30 is getting a little long in the tooth and is in need of a new set of power tubes.  These amps are known to be hard on power tubes, and after 12 or so years of light to moderate use, they're getting a little noisy/mushy.  New preamp tubes helped a lot but something stout and fast needs to go in for power.  A set of JJ's from back in the day have given good service, but I know there are other/better options available these days

What say we?

[Jakeboy]

For the new production, Brian Gerhard at TopHat  prefers the new Mullard which of course is not Mullard. He feels the JJs are too stiff, but you may want that.

I love the old glass…old Sylvania gray or blackplates are EXCELLENT for el84 amps. They bring the chime and the grit and last a long time. I often buy used old glass that tests as new or I scavenge from old organs. Old glass typically lasts a long, long time.

If you can find old Phillips or real Mullard el84s, they sound just great as well. But the Syls are my faves.

[Dutchman]

I agree with @Jakeboy the old glass is the best there's The Russian 6N14N that get's some love from Dr Z. My favorite is the old glass GE  7189. They just have what I like better than the others.

[tomteriffic]

I have a box full of 'em.  New, old, vintage, throwaway, you name it.  But I was under the impression that with a cathode biased amp like this, you really, really need them to be matched.  And I'm sure I don't have a quartet of anything.  Am I correct in this belief?

Oh, and if I had to choose, I'd probably lean toward the stiffer side.  I live in the squeaky clean to mild overdrive neighborhood.

 

[Jakeboy]

@tomteriffic said: Oh, and if I had to choose, I'd probably lean toward the stiffer side.

Wouldn’t we all?.?

[Jakeboy]

I am becoming less and less worried about perfect tube matching with cathode biased amps…As long as nothing is redplating, the tubes are not inducing an undue amount of hum, and most importantly, IT SOUNDS GOOD, I say rock on.  But that is me. On my fixed bias amps with bias measurement points and bias pots, I am all over it, making  sure I have  them matched and running at 70%. Even then, if the tubes are close, not redplating and sound great and are not over 70%, it is game on.

[tomteriffic]

Maybe I'll dig out the old hand-cranked steam powered tube tester and learn what I can about some of these and put a set together.

PS A new Mullard in V1 made a big difference.

[LucSulla]

The one thing I've heard good about JJs is they handle the higher plate voltages that some of the little monster Bogner, Friedmans, Soldanos and so on use to make their EL84 amps feel more like EL34s.   Supposedly, YMMV on older tubes.  I've no first hand experience with that though - Hell, now that I think about it, I'm not sure if my Budda has JJs or Mullards in it.  Also, I'm not sure a Classic 30 is smacking them that hard to begin with.  Twelve years would argue probably now.

[tomteriffic]

Back when I last retubed it, it was JJ's all across.  The Classic 30 had a reputation for being hard on tubes, presumably because of the plate voltages.  And, as you noted the JJ's are good at handling those.  Anyway, it needs new glass now, so down to Buzzard Gulch I go to see what I can roll up before I spend any significant dough.

 

[JGale]

Add my one and a half cents here for the Sylvania EL84. Just got a set from Brent Jesse, Inc. for my Mooer Tube Engine. It runs at 375V on the plates.

Tom. Try a 5751 in V1. I have one I will send you. 70% of the gain of a 12AX7, quiet and rich. Let's you use more of the amps other fine qualities while staying within loudness and gain limits.

Like it or not I got most of my suggestions off TGP. They had the best narrative and have a couple dealers that act as referees of a sort, certainly as historians.

[HSB0531]

I'll assume you mean the Peavey Classic 30.

If the amp is 12 years old, I'd definitely replace all the electrolytic capacitors, especially since it's a tube circuit (heat).

These days, electrolytic capacitors have smaller packaging and it allows you to replace them with a higher voltage rating at roughly the same size dimensions.

Also, try to get ones rated at either 105 Deg. Celsius or 125 Deg. Celsius temperature rating.

Increasing both voltage and temperature rating will vastly extend the life of the caps, and improve the sound of the amp.

It may even extend the life of the tubes if you go with a higher 105 or 125 Deg. C. temp. rating and closer tolerance rating (stock units are typically rated at 85 Deg. C.) because the cap. will remain more stable and closer to spec. 

Cost of the parts is minimal and there's several companies to choose from like:

https://www.mouser.com/Search/Refine?N=12013589

Here's a link to the Classic 30 circuit:

http://www.bustedgear.com/images/schematics/Peavey_classic-30.pdf

 

 

 

[Len]

I like the way Tung-Sol EL84's sound in all of my Orange amps ...