hot rod princeton

[scole]

anybody build one of these?

[loudthud]

I haven't built one but it looks like a well done layout. Should be a fun project.

[scole]

is that boost switch connected correctly?

[loudthud]

The Boost switch is wired to act like an all or nothing presence control.

[scole]

what is the boost sw turning off and on? its wired across the 22k resistor, but it doesnt seem like it would turn anything off or on.

[Johno]

The switch bypasses the 22K resisitor in the cathode leg of V2B, thus putting the 0.68 cap directly to ground. That should have the effect of rolling off more low end and providing more gain in that stage of the amp

[loudthud]

The 22K doesn't do much when the switch is open except it does make it so you don't get a click through the speaker when you close the switch. It gives a treble boost like a presence pot would. You can tweek on the value of the cap to adjust the frequency where the boost kicks in. Bigger cap for lower frequency. You don't need a 600V part for the 0.68uF. A 10V part will work fine but don't use one of those baby electrolytics, use ceramic, mylar or poly.