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FDP Forum / Miscellaneous and Non-Fender Topics / My question about tubes

Contributing Member


Too Much GAS
Jul 1st, 2017 06:42 AM   Edit   Profile  

First of all, I know very little about tubes/valves.

I have a Vox AC15H1TV with the Celestion Alnico Blue speaker. It has Mullard EL84's in it already. They were in it when I bought it used. It has Svetlana 12AX7's in it. A JJ EZ81 and another tube I couldn't find a definitive number on.

Would there be any noticeable sonic difference if I were to change out any of these tubes? The amp sounds really good to me as it is.

I'm not really gigging with the amp so longevity is not really an issue.

Moderator Emeritus
(with many stars)

NW Pennsylvania

Jul 1st, 2017 07:03 AM   Edit   Profile  

If it already sounds good then why change it?

Contributing Member


Jul 1st, 2017 07:10 AM   Edit   Profile  

A change in tubes has almost always made a noticeable difference to me, especially if changing to a different make. For instance, swapping JJ 6V6's for Tung Sol made a huge difference in my Princeton Reverb II. I like JJ EL84's, but not their 6V6.

But, if it ain't broke...

Contributing Member

The rain sounds like

a round of applause
Jul 1st, 2017 12:20 PM   Edit   Profile  

There's nothing wrong with taste-testing different tubes to satisfy your curiosity.

The only thing to keep in mind is there's a right way and a wrong way to remove and install tubes. If you get too physical with 'em, you'll stress the sockets and cause the pin contacts to become loose--and that is not good. Be gentle with 'em.



Jul 1st, 2017 02:53 PM   Edit   Profile  

Yes, there might be a noticeable difference.

I assume that you mean in a good way.
There might also be a noticeable difference in a bad way.
Or none at all.

If you haven't done it, and you gig out with this amp, at a minimum I would buy a spare set of tubes. And try them out when you get them to make sure that they actually work.


Pocono Mountains USA

Wanderin eye and a smokin gun...
Jul 2nd, 2017 02:31 AM   Edit   Profile  

I would go ahead and experiment, but honestly the Mullards RI are nice tubes as well as the Svetlana's. I would be in no hurry to replace them.



Why do I keep fixing things that work?
Jul 2nd, 2017 09:47 AM   Edit   Profile  

The only problem I've had is that, although some of my older vintage tubes sound wonderful, in a combo style amp, the longer plate 12AX7's are more prone to becoming microphonic due to vibration. They sound glorious for a short time but have had to go to a more stout, shorter plate style of tubes.
I've had good sound and tone from JJ's (sometimes a smidge darker) and Tung-Sol, if you need to go a shade brighter.
But another tube I like is the Sovtek 12AX7's. These are a rugged and good sounding tube with good distortion characteristics.
So, in a combo style amp, vibration is the enemy and your preamp tubes should be of the shorter plate design and will result in longer life.
Just some food for thought. ......

Contributing Member

American Patriot

About as ordinary as you can get.
Jul 2nd, 2017 08:24 PM   Edit   Profile  

Why change? But if you do, change them one at a time.



Jul 3rd, 2017 11:17 PM   Edit   Profile  

"Why change? But if you do, change them one at a time."

Exactly! Change one and make sure it works and doesn't change the sound for the worse. If you do a wholesale change at one time you will have a harder time finding the one or even two that cause a negative effect on the amp

"The only thing to keep in mind is there's a right way and a wrong way to remove and install tubes."

When removing a tube, very gently and slightly rock the tube back and forth while pulling on the tube. When reinstalling make sure no pins are bent and they are inserted in the correct position so as not to mess the tube and tube socket up. DO NOT FORCE

Last, I like Tung Sol 12AX7's and JJ output tubes. And oh how I love an EL84 Amp's tone :)

FDP Forum / Miscellaneous and Non-Fender Topics / My question about tubes

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