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The volume boost on some silvferface Fender amps is gained by stealing some of the signal just before it's sent to the reverb springs. I find the boost unappealing because before the signal is sent to the tube that drives the reverb springs, it passes through a 500pf cap (visible on the horizontal black line near the top of the schematic). This removes some of the bass frequencies which sound muddy in the reverb, but when you steal this signal and use it for boost, the signal is much too bright.
A few notes. The 10K resistor was what I found in my amp, the schematic showed it as 1K. Also, I found a 1K resistor after the pull-boost switch that wasn't on the schematic. Things may vary in your amp as well.
Tremolo switch
This leaves an unused pull-on switch on the volume knob. I used it to open the signal path to the tremolo. This adds just a little bit of volume, because even when the tremolo is off, the 50K Intensity pot steals a little of the signal. Find the wire coming off the outside lug of the Intensity pot (the outside lug that's not grounded), and follow it to the fiber board. Unsolder it at the board, noting the lug it is attached to. Run it to one pole of the pull-boost switch. Then add a wire from the other pole of the pull-boost switch to the lug on the fiber board.
This works well for me, since I don't use tremolo much. With the knob in, the tremolo doesn't work, and I get a little more volume. Pull the knob and the tremolo works like a stock amp. When you pull the switch there's a pop which is especially noticeable the first time you turn the tremolo on, but after that, switching is much quieter.
Update
If you put a 1M resistor across the switch poles, it will eliminate the pop entirely.
Refer to the above schematic to see how I removed this"feature." Everything in red is removed. Leave the switch on the back of the volume pot of course. The end of the 220K resistor that was attached to the 10K resistor now has to be grounded. (You could probably just leave the 10K resistor in, but I removed it.) That's it.
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