Originally posted by Valvehead
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Yes, but not one that I've never liked much. Triode mode when pushed just doesn't sound so great IMHO. Then consider the voltages, you'll routinely have 1KV across the plates side of the switch, and on occasions, could have considerably more. So arc-over is a risk unless care is taken. It's a tough call to find a switch that can operate with high DC voltages applied as any arc doesn't self extinguish as it does with commutated AC. That's why the switch should only be operated with the amp off or in standby. Forget to do it right and the switch may get toasted. Also half power is hardly any quieter than full power.
I suggest that a better way to get "half power" and to get a useful new dimension to the sound, would be to use cathode bias. Your switch has to remove the bias supply and add two resistors (guess 680 ohm 5W) in series with the cathodes. For KT66's separate cathode resistors are required. This means using a 3PDT switch but only low voltages are switched. Still best to be in standby to avoid loud pops but if you forget, no harm is done.
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