Twin reverb Send/Return controls

[ThisLifeILead]

Im building a custom twin reverb but i want better control of the reverb. Send/return and level controls. working from the standard fender design
Correct me if im wrong on this...
Send level i could replace the 1M grid leak resistor on the driver input stage with a 1Meg pot. the return stage i can replace the grid leak with a 220K pot. Both audio taper im assuming?

[Leo_Gnardo]

Send level i could replace the 1M grid leak resistor on the driver input stage with a 1Meg pot. the return stage i can replace the grid leak with a 220K pot. Both audio taper im assuming?

You're borrowing a good idea from the old Fender outboard reverb: the "dwell" control which controls how hard the drive circuit it hitting the reverb tank. It may make sense to put a resistor on the "bottom" of your dwell control, there's no point in going all the way to zero.

At the other end there's no point in adding another control on the reverb return. Go full strength to the recovery preamp or you'll be increasing the noise floor. Another good idea to borrow from the outboard reverb is a tone control. If there's still way too much reverb you can pad the reverb volume pot - I've done this on lots of Fenders. Typically 150K to 470K on top of the reverb control, and you can bypass that resistor with a brightness cap if you wish. Then you can open up the reverb pot to whatever point makes sense to you. Rigged like that, you'll have a lot of good alternatives to the usual Fender maximum-surf reverb setup.

[ThisLifeILead]

love it. Thanks Leo, i was thinking the same for the recovery control, in that you want as much signal as possible and thats a sensitive section.

[Enzo]

Not to be overly technical, but you already have a level control on the return, it is the reverb control on the panel.


You probably play almost always on the vibrato channel, and rarely use the "normal" channel, right? If so, try this. Run a RCA to 1/4 male cord from the pan OUTPUT jack up to the normal channel input jack. Now the normal channel controls become your reverb circuit, you have the volume for level, and the tone controls for tone. Fun to try and requires no mods to the amp, so you can restore it to stock in 10 seconds.

As to the dwell control on the drive side. Yes, a 1 meg pot in place of the grid return resistor. I recommend at first you tack a small trimmer pot in there. Now you can experiment with the range of settings while the chassis is out to see what you think. Try that before you take the step of mounting a new control on the chassis, I especially hate drilling holes in my Fender chassis.

I suggest this because in my experience, at first it is a fun control to fiddle with, but after a few days, we wind up just turning the drive dwell all the way up and forgetting it. And if that will be the case, why screw up the chassis?