Hi All,
I'm continuing to think about building a stand-alone pre-amp for exploring high-gain ideas. In my last post we discussed power supplies. One important design choice is how high in voltage I want to go. Looking at examples out on the web, there is a huge range of voltages applied to the pre-amp tubes. Here are some example plate voltages used on 12AX7 pre-amp tubes:
260V Fender 65 Deluxe Reverb Reissue (my current amp) schematic
300V First stages on Marshall JCM-800. pre-amp, power-supply
357V First stages on Mesa Boogie MK II. schemtic
359V First stages of Soldano SLO-100 schematic
402V First stages of Mesa Dual Rectifier schematic
So, my question is...what is the effect of the voltage supplied to the pre-amp tubes? How does it affect the sound? Also, why do these amps almost always seem to ratchet up the voltage for the later pre-amp tubes? How does it affect the qualities of the overdrive?
Thanks,
Chip
I'm continuing to think about building a stand-alone pre-amp for exploring high-gain ideas. In my last post we discussed power supplies. One important design choice is how high in voltage I want to go. Looking at examples out on the web, there is a huge range of voltages applied to the pre-amp tubes. Here are some example plate voltages used on 12AX7 pre-amp tubes:
260V Fender 65 Deluxe Reverb Reissue (my current amp) schematic
300V First stages on Marshall JCM-800. pre-amp, power-supply
357V First stages on Mesa Boogie MK II. schemtic
359V First stages of Soldano SLO-100 schematic
402V First stages of Mesa Dual Rectifier schematic
So, my question is...what is the effect of the voltage supplied to the pre-amp tubes? How does it affect the sound? Also, why do these amps almost always seem to ratchet up the voltage for the later pre-amp tubes? How does it affect the qualities of the overdrive?
Thanks,
Chip
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