What tubes for the PI on a Marshall amp?

[Kommerzbassist]

Hey guys, I was wondering which tubes would give you the best classic Marshall power stage drive when used in the phase inverter position... if that makes sense in any way.

 

[Vasshu the humanoid typhoon]

Re: What tubes for the PI on a Marshall amp?

Normally some lowgaintube, in most classic amps it gives the most tight and glassy oldstyle feel and sound.

 

[Kommerzbassist]

Re: What tubes for the PI on a Marshall amp?

Hm thanks man... any specific tubes?

 

[Vasshu the humanoid typhoon]

Re: What tubes for the PI on a Marshall amp?

12At7 I think it is.
Somebody correct me if I have remembered it wrong

 

[shredaholic]

Re: What tubes for the PI on a Marshall amp?

Try getting a slightly used Mullard 12AT7 from eBay, they're very cheap compared to the Mullard 12AX7, but sound great and you won't care that it's slightly used as it'll last loads longer than any modern production tube anyway.

 

[STRATDELUXER97]

Re: What tubes for the PI on a Marshall amp?

You want a 12AX7 in the Marshall...

 

[Vasshu the humanoid typhoon]

Re: What tubes for the PI on a Marshall amp?

Yeah, but our ancient builder of dem hot glassy bubble amps, says that using a lowgain tube will tighten things up, and using a ax7 will make it more spongy

 

[Kommerzbassist]

Re: What tubes for the PI on a Marshall amp?

Ah looks like we have some controversy here...

 

[shredaholic]

Re: What tubes for the PI on a Marshall amp?

It's a matter of taste I guess. Do you like phase inverter distortion or preamp distortion more? I love phase inverter distortion, it's what most people associate in a Marshall with power amp distortion, to get more of it you want a higher gain tube like a 12AX7.

 

[STRATDELUXER97]

Re: What tubes for the PI on a Marshall amp?

Yeah, but our ancient builder of dem hot glassy bubble amps, says that using a lowgain tube will tighten things up, and using a ax7 will make it more spongy

It won't tighten the amp up,but it will clean the preamp up and give the amp more clean headroom...The tightness comes from the power supply,output section,and the negative feedback part of the amp..C Mon buddy,you should know this stuff....:6:

A 12AT7 sounds horrible in a Marshall to my ears.... BF Fenders is a different story though...YMMV?

 

[Lewguitar]

Re: What tubes for the PI on a Marshall amp?

You want a 12AX7 in the Marshall...

Yep...12at7 for blackface Fender and 12ax7 for Marshalls. Lew

 

[STRATDELUXER97]

Re: What tubes for the PI on a Marshall amp?

Yep...12at7 for blackface Fender and 12ax7 for Marshalls. Lew

A guy can use a 12AT7 in the PI of a Marshall,but it just doesn't sound right to me....In a BF Fender amp I find just the opposite and I don't like what a 12AX7 does...

 

[Lewguitar]

Re: What tubes for the PI on a Marshall amp?

A guy can use a 12AT7 in the PI of a Marshall,but it just doesn't sound right to me....In a BF Fender amp I find just the opposite and I don't like what a 12AX7 does...

I agree. And a guy can use a 12ax7 in place of a 12at7 in a blackface Fender if he wants a gainier, grainier tone. But generally, I like 12ax7's in Marshalls and 12at7 in Fenders. Just sounds "right" to me. But everyone should experiment and see...you're not going to hurt anything and then you'll know what YOU like. Lew

 

[STRATDELUXER97]

Re: What tubes for the PI on a Marshall amp?

I agree. And a guy can use a 12ax7 in place of a 12at7 in a blackface Fender if he wants a gainier, grainier tone. But generally, I like 12ax7's in Marshalls and 12at7 in Fenders. Just sounds "right" to me. But everyone should experiment and see...you're not going to hurt anything and then you'll know what YOU like. Lew

Exactly buddy..As usual I agree...:banana:

 

[Kommerzbassist]

Re: What tubes for the PI on a Marshall amp?

Ok, so what specific brabd/type of 12ax7 would you recommend for that position if I want mucho Marshall crunch?

 

[STRATDELUXER97]

Re: What tubes for the PI on a Marshall amp?

Ok, so what specific brabd/type of 12ax7 would you recommend for that position if I want mucho Marshall crunch?

You don't want your PI tube to be the one to get you the crunch....V1 is the tube you need to hone in on and the PI needs a strong,reliable tube,but it doesn't have to be high gain.

 

[shredaholic]

Re: What tubes for the PI on a Marshall amp?

I disagree a bit - I've noticed crunch varies quite a bit when swapping out 12AX7's in V3. The effect is less noticeable in V3 than V1 than you'd expect, but I'd still take tonal properties of a phase inverter tube over strength.

The more upper mid emphasis the tube has, the more crunch you'll get. For crunch, a Mullard or Valvo will probably be the crunchiest, if you like to retain crunch but with a bit more "ballsy" tone an RFT would be great for that.

 

[STRATDELUXER97]

Re: What tubes for the PI on a Marshall amp?

I disagree a bit - I've noticed crunch varies quite a bit when swapping out 12AX7's in V3. The effect is less noticeable in V3 than V1 than you'd expect, but I'd still take tonal properties of a phase inverter tube over strength.

The more upper mid emphasis the tube has, the more crunch you'll get. For crunch, a Mullard or Valvo will probably be the crunchiest, if you like to retain crunch but with a bit more "ballsy" tone an RFT would be great for that.

Remember though that the PI tube is more about function then tone though A strong,balanced from side to side PI tube is really what this position benefits from.
..Most of the overall tonality we hear comes from the preamp and not the PI by itself...V1 is the main tube to tweak.

 

[Kommerzbassist]

Re: What tubes for the PI on a Marshall amp?

Ok thanks people. I think I've heard enough

 

[Rocker35]

Re: What tubes for the PI on a Marshall amp?

A balanced JJ is real nice in the PI position.