6eu7 vs 12ax7

[myamp]

They look the same to me just different pin orientation.

[markh]

Functionally (transconductance, etc.) they're the same. The "6" of course only has a single 6V heater instead of a CT 12 volt.

Most of the olden days amp makers chose tubes based on function, cost, and availability (not because they were copying something . The Gibson engineer(s) just liked the 6EU7 better, for whatever reason. It may be as simple as he had used it before and was familiar with it.

--mark

[markh]

It's hard to imagine a dual triode more microphonic than a 12AX7! I would hope it'd be the same or better.

--mark