12ax7 of 12at7 in p1

[rs16iandy]

hi boogie owners i have an f50 and was looking at swapping out the 12ax7 in p1 for a 12at7 what are the pros and cons?
i have heard it macks the amps sound more open but i have also heard it is less dynamic?
cheers andy

 

[94Tremoverb]

I would say it makes it more dynamic, not less. It does reduce gain a bit - so if your idea of 'dynamic' is "as loud as possible" then it does reduce that - but my idea of dynamic is "more responsive to changes in technique, guitar volume and pedal settings". It also widens the tone and makes it deeper, clearer and less midrangy.

I've put 12AT7s in the PI in every Mesa I've ever owned, and some for friends and customers, and it has (in my opinion) improved every one of them. Perhaps if I was looking for all-out rock/metal tones I would think otherwise, but I'm not.

 

[topcat0399]

It certainly can't hurt anything to give it a try - its on my tube roll list of possibilities.

 

[EtherealWidow]

I put 12AU7's in the first and third positions of my Express. I don't like the amp with the 12AX7's in all positions. The amp is a LOT less compressed now. Absolutely pleasant

 

[yeti]

mullard cv4024 is a good tube to tame things on the gain side, but improve clarity and color.

 

[212Mavguy]

+1 for cv4024.