Studio Preamp rev.1 vs rev.2

[ytse_jam]

I came across an old post on this board, and discovered there are two revisions of the Studio Preamp, the first (the one I have) with a 12AT7 in V5 (reverb driver I suppose), the second with a 12AX7.
Does anyone know if there is any other difference between the two revisions?

Another question, how would the reverb be affected if I put a 12AX7 instead of the current 12AT7? Any issues with doing so?

 

[CudBucket]

I'd imagine a 12AX7 would generate some noise on higher reverb settings due to it's higher gain.

 

[bunyok23]

yes there is. one is very close to c+ and the other one is tighter like the mark iv

 

[ytse_jam]

yes there is. one is very close to c+ and the other one is tighter like the mark iv

really? where did you get that info? any link? I suppose the earlier Studios were the closest to C+ specs, right?

 

[bunyok23]

on schematics. the one i have now seems tighter like the mark iv