Tube Amp Archive

Can you hear the difference between a split load and
a non-split load plate resistor?

Then my work here is done.

The schematic for the Red Knob Twin has been widely
available for a number of years.

However, the Layout of the printed circuit board
has not been widely circulated.

As I indicated, Fender may have this in their Red Knob Twin
documentation.

The correct name for this amp is "The Twin."

I don't believe that is correct. The Red Knob Twin had channel switching, an effects loop, and channel combining input jacks, in addition to separate channel input jacks. None of these features were present in the 70s Fender Silverface Twins. Fender may have a printed circuit board diagram available...

Take a look at the schematic for the Fender Twin II. The effects loop in that amp has a send level control and a return level control. It uses both sides of a 12ax7, and is out of the circuit when nothing is plugged into the return jack. The switching jack for the return is available from Mouser Ele...

You might try changing the .1 mfd. tone stack cap to
.047.

Sorry for the double post.
You could also try a 500k pot instead of the 1 meg.
The general rule is: the lower the value of the pot, the more
signal it will bleed to ground.

Try a 1 meg resistor from the middle lug of the pot to ground. This will decrease the pot's resistance to ground (compared to stock) as the pot is turned up. The greater the resistor value, the less effect it will have; the smaller the value of the resistor, the more effect it will have.