12AX7 and 12AY7

[Witek]

Would a 12AX7 tube work in a 12AY7 tube slot without damage, distortion or other bad consequences?

[billdurham]

Originally Posted by Witek

Would a 12AX7 tube work in a 12AY7 tube slot without damage, distortion or other bad consequences?

It depends on how you define "work"! Sorry for the Clinton esq answer, but the AX7 has more gain. Depending on what the tube is doing, you could have distortion down stream of the AX7 because of the additional gain.

BD

[Timbre Wolf]

Originally Posted by billdurham

you could have distortion down stream of the AX7 because of the additional gain

Good heavens!! Wouldn't want distortion, now!

Maybe unwanted or excessive distortion? Doesn't hurt to try it, Witek, and determine if you like it or not.

- Thom

[Blue Strat]

Yep, no damage will be done so it's ok to try it.

"Clinton-esque"? ROFL!

[brad347]

Clinton... hmm... seems like we could've done worse... oh wait...

Yes, no damage will result. Try it, you may like it!

[Topcat]

Those babies are interchangable without a problem. They will give you different gain structures. So have at it and post us your findings.

Mr.T

[Curt]

Originally Posted by Witek

Would a 12AX7 tube work in a 12AY7 tube slot without damage, distortion or other bad consequences?

Funny, when he mentioned distortion. another president came to mind.

[Blue Strat]

Originally Posted by brad347

Clinton... hmm... seems like we could've done worse... oh wait...

LOL! d'ya think?


You're in Paterson? I grew up in Fair Lawn.

[brad347]

cool! West Paterson actually right on the corner where paterson, totowa, and west paterson all collide. One semester left in my master's degree at William Paterson University...

[rockon1]

Might the higher gain of the 12AX7 be dangerous to use in some circuits that call for a considerably lower gain tube such as the 12AY7? I can understand going from higher to lower but lower to higher? Just a thought.

[Timbre Wolf]

Originally Posted by rockon1

Might the higher gain of the 12AX7 be dangerous to use in some circuits that call for a considerably lower gain tube such as the 12AY7? I can understand going from higher to lower but lower to higher? Just a thought.

I don't know of any classic amp designs where that'd be a problem, which is why I didn't mention it. But if someone else knows that this issue would be a problem, please speak up (and name the amp).

- T

[donnyjaguar]

If the 12AY7 is being used in a circuit where the maximum power dissipation is being exploited then putting a 12AX7A in there is not a good idea.

That said, its pretty rare that the above is true although I've seen it in cathode followers and phase splitters.

DJ

[Jaybird03]

I found this interesting stuff on Bills Blues Jr. Mod Page-----"Everybody talks about how you can tailor the tone of an amp by swapping tubes in various gain stages or the phase inverter. But how many people have actually done it? And how many have actually documented what the swaps do?
Call me crazy, but I went out and bought $80 worth of tubes and ran them through one of my Blues Juniors, and took scope photos to document the actual effect on preamp distortion and power tube distortion.
The first thing you need to know is that the ubiquitous 12AX7 dual triode is just one member of a family of tubes that have different amounts of gain. The 12AX7 has the most, and is rated at 100. Here are the ratings of its siblings:
12AX7/100, 12AT7/60, 12AY7/45, 12AV7/41, 12AU7/20,
So the 12AV7 has less than half the gain of a 12AX7, while a 12AU7 has only one-fifth the gain. The 5751 is also in the family, and is supposedly between a 12AX7 and a 12AT7. I tried several, and couldn't find any difference between them and a 12AX7 in this test. There's also a weird cousin, the 12DW7, which has non-identical triodes. One has the gain of a 12AX7, while the other has the gain of a 12AU7. The actual amount of gain in the circuit is determined by the voltages applied and the components selected by the circuit designer. That stuff is hard to change without a soldering iron--and some serious knowledge of what you're doing. But anybody can change tubes."
I own an Alamo Challenger amp that runs a 12AX7 . It was too much so by using a 12AT7 the amp is now perfect for my harp mic.

[Old Tele man]

[Timbre Wolf]

Originally Posted by Old Tele man

OTM: does this data reflect the "UPDATE - 12AV7 specs updated to 150Vp data (no 250Vp data found in GE, Tung-Sol or RCA data sheets)" info you posted a while back?

- Thom