Quote Originally Posted by Ghostman View Post
Is there a tonal difference with the Preamp in the PI stage? Also, what happens with differing preamp gain rates, such as a low 5751 vs a hot 12AX7?
It's way more subtle tone wise in the PI slot, but gain factor will make a noticeable difference. Also, I would recommend getting a high / low gain tube in the same tube the amp is designed with (12AX7 / ECC83 in most cases) before swapping to a lower output tube like a 5751.