Mod: add $35.00
On the plexi and metal face amps up through 1972, there was a
.68 cap on the second stage cathode circuit. It gave an
increase in gain and midrange. My 50 watts come stock with
this cap but you can order this amp with a small switch (that
I install on the front panel) that takes this cap in and out
of the circuit.
Mod: add $100.00
I also offer my gain mod, which works like this: the input
tube has two sides, channel one uses one half of the tube,
channel two uses the other half. On the gain mod, one
half of the tube drives the other half of the tube using the
volume two pot as the gain control and the volume one pot as
the volume control. This gives you a
great amount of controllable gain. When you plug into
the channel one input, it bypasses the extra gain stage and
works like a stock plexi preamp. Both channels work with a
master volume that I install on the front or back of the amp.
The master volume is included in the gain stage mod.
Feedback Control: add $35.00
Also available is the optional negative feedback control. In
these amps the negative feedback resistor varied from 47k to 100k
depending on the year. With the control (mounted on back of amp) you
can adjust this from 47k to 100k. This will give you more or less
power amp gain.
Master Volume Mod: add $50.00
Pre or post Pl master volume. I install these on the rear of the amp
or in the front in an unused input jack hole.
Adjustable line out
Zero Loss Effects
loop with bypass switch add $150.00