(Moved from Tubes section.)
While I have this amp apart, I wanted to understand a couple things more clearly. One is a possible mod.
1st: What is the purpose of this resistor (R109) and cap (C61) between audio ground and chassis ground? I've seen this before in other audio circuits. Why the components between grounds? I don't plan to alter this. Just curious why. (The input jack is isolated from the chassis.)
2nd: It seems odd that they provided a DC voltage for the filaments of the 1st 12AX7, but AC for other three. Would there be any harm in just running the DC to all four 12AX7 heaters? I'd sub 1N5407's for the 1N4007's to account for the extra current load.
Thanks all.
While I have this amp apart, I wanted to understand a couple things more clearly. One is a possible mod.
1st: What is the purpose of this resistor (R109) and cap (C61) between audio ground and chassis ground? I've seen this before in other audio circuits. Why the components between grounds? I don't plan to alter this. Just curious why. (The input jack is isolated from the chassis.)
2nd: It seems odd that they provided a DC voltage for the filaments of the 1st 12AX7, but AC for other three. Would there be any harm in just running the DC to all four 12AX7 heaters? I'd sub 1N5407's for the 1N4007's to account for the extra current load.
Thanks all.
