Mark IV question

[deny]

I've got a Mark IVa and on the chassis it has V4 marked as having a 12at7, so that's what I put in there. My question is, would a 12ax7 be fine in V4? I'm still new to this amp, and tubes to an extent. Any help would be appreciated.

 

[devilrob1979]

That's the reverb tube and it'll be fine.

 

[Russ]

Actually the 12at7 needs to stay 12at7 for it to sound right.

Replacing the 12at7 with a 12ax7 adds a bit of gain there that makes it sound odd.

It is safe to run a 12ax7 there but I found that, like I was told by Mesa, it just makes the reverb sound different.

... and yes, I do own a Mark IVa.

 

[Shep]

Actually the 12at7 needs to stay 12at7 for it to sound right.

Replacing the 12at7 with a 12ax7 adds a bit of gain there that makes it sound odd.

It is safe to run a 12ax7 there but I found that, like I was told by Mesa, it just makes the reverb sound different.

... and yes, I do own a Mark IVa.

yeah i agree,its best to stay with what it came with..

 

[DFGeneer]

I have Mark IV a. Got it month ago, and it came with all 12AX7 preamp tubes. Reverb sounds fine. I don't really know how would it sound with 12AT7 on V4, but I can say using 12AX7 is no problem at all.

 

[deny]

I don't really use the reverb, so I was thinking about moving the 12at7 to V5. Thanks for the answers everyone.