12ax7 of 12at7 in p1

Talk about tubes and their effect on your tone

Moderators: Guitarzan, Grandor, ned

Post Reply
Mark I
Posts: 36
Joined: Fri Mar 11, 2011 5:32 pm

12ax7 of 12at7 in p1

Post by rs16iandy » Wed May 04, 2011 10:58 am

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

Single Recto
Posts: 1340
Joined: Sat Dec 05, 2009 1:07 pm

Re: 12ax7 of 12at7 in p1

Post by 94Tremoverb » Wed May 04, 2011 5:34 pm

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.

Mark III
Posts: 231
Joined: Sun Feb 28, 2010 9:31 pm
Location: cheeseland

Re: 12ax7 of 12at7 in p1

Post by topcat0399 » Wed May 04, 2011 5:45 pm

It certainly can't hurt anything to give it a try - its on my tube roll list of possibilities.
Me -------> 1973 Gibson Les Paul Standard------->1991 Mesa Boogie Mark IVa/b Combo -------> World.

Mark IV
Posts: 687
Joined: Mon Jul 06, 2009 11:20 pm
Location: Desert

Re: 12ax7 of 12at7 in p1

Post by EtherealWidow » Wed May 04, 2011 9:02 pm

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
Ibanez Xiphos
CMATMODS Deluxe Signa Comp
5:25 Head
Boss Giga Delay
Boogafunk Thiele

User avatar
Mark II
Posts: 116
Joined: Sat Aug 21, 2010 12:15 pm

Re: 12ax7 of 12at7 in p1

Post by yeti » Thu May 12, 2011 10:50 am

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

Mark IV
Posts: 754
Joined: Fri Oct 05, 2007 11:39 am
Location: Park City, UT

Re: 12ax7 of 12at7 in p1

Post by 212Mavguy » Mon May 16, 2011 7:42 am

+1 for cv4024.

Post Reply