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.
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.
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1) you'll get better results in the Musical Instruments section, this one focuses more into HiFi
2) DC filaments are an advantage in the very first triode, catering to the weakest signal, doubly so in a high gain amp as the Blue Voodoo, anywhere else it's not needed.
3) that circuit ground to chassis ground separation network is intended to reduce ground loop hum, a real problem in complex setups such as recording studio, not too important in guitar>amp setups, even if adding a few pedals.
Definitely needed if you add rack type effects.
2) DC filaments are an advantage in the very first triode, catering to the weakest signal, doubly so in a high gain amp as the Blue Voodoo, anywhere else it's not needed.
3) that circuit ground to chassis ground separation network is intended to reduce ground loop hum, a real problem in complex setups such as recording studio, not too important in guitar>amp setups, even if adding a few pedals.
Definitely needed if you add rack type effects.
Guitar amplifiers are found in the Instruments and Amps threads of diyAudio.com
Ground loops are found in both the Tubes / Valves threads, and Instruments and Amps threads.
Murphy's law applies in both areas.
Safety First!
Prevent the "Surviving Spouse Syndrome".
It is a Mean thing to say that Karl Friedrich Gauss was an Average man, who was Centered on his Gaussian Curve.
Ground loops are found in both the Tubes / Valves threads, and Instruments and Amps threads.
Murphy's law applies in both areas.
Safety First!
Prevent the "Surviving Spouse Syndrome".
It is a Mean thing to say that Karl Friedrich Gauss was an Average man, who was Centered on his Gaussian Curve.
