Adding Effects Loop to Custom Vibro Champ Build

[Potato Cakes]

Hello everyone,

I am nearing completion of a modded Vibro Champ build and one of the things that I cannot decide is the placement of the effects loop that is being added. Usually this is inserted before the phase inverter but in this case, I wish to have the loop after the inverter as this is used for the tremolo function and I want it to be pre pedal board. I can wire the switched jacks so that with the loop in or out there is always 0.02uF before the power tube.

I know this alteration seems excessive with such a simple amp, but I prefer how much cleaner and more detailed my effect pedals sound using a post preamp insert rather than everything directly into the amp's input. I am wondering if anyone one here has performed this modification and if there were any surprises that had to be addressed.

Schematic attached for reference.

Thanks!

Paul

 

[merlin]

There is no phase inverter in a single-ended amp... Put the FX loop before the power tube, what's the problem? (Obviously you'll need a gain stage for recovery)

 

[Potato Cakes]

There is no phase inverter in a single-ended amp... Put the FX loop before the power tube, what's the problem? (Obviously you'll need a gain stage for recovery)

You're correct. I was mistaking the tube section before the power tube as the inverter.

The pedals that would be in the loop are buffered, so I do not expect much if any loss.

Thanks!

Paul

 

[merlin]

The pedals that would be in the loop are buffered, so I do not expect much if any loss.

Yes, but pedals cannot handle signals of tens of volts! So you have no choice but to attenuate the signal before it reaches the pedals, then boost it back up again for the power tube.