Simul-class question: where should my "best pair" of tubes go?

[erickompositör72]

Just curious, if you only have one pair of your best tubes, would you put them in the Class A or A/B sockets?

My favorite are my STR 415's, but at the moment, I just have 1 pair.

I have four STR 430's, and two STR 440's


Just curious how people perceive the sounds of particular tubes in Class A vs Class A/B sockets

 

[woodbutcher65]

Because the outer pair of sockets is the only pair that can take either 6L6 types or EL34 types, it's obvious that if your favorite tubes are EL34s, they need to be in the outer socket pair. But if they're 6L6 types, it literally makes no difference at all whether you choose the inner pair or the outer pair of sockets.

 

[GJgo]

IMO it's really more about getting the correct bias range. Personally I want to set mine up so the A/B slots are around 70% dissipation & the A slots are around 80% dissipation.

For a Mark II & III:
For A/B this is "usually" Mesa "green or grey", in the 35-40 mA range.
For A w/ 6L6 this is "usually" Mesa "red or yellow", in the 45-50 mA range.

Also, it was explained to me once that in the Simul amps most of the tone comes from the A slots & the A/B slots are more about adding HP. I never verified this with Mike, though.

 

[erickompositör72]

Also, it was explained to me once that in the Simul amps most of the tone comes from the A slots & the A/B slots are more about adding HP. I never verified this with Mike, though.

I guess I had kind of intuitively assumed this (again, no real evidence to back it up)...