Installing a "power amp in"

[hebaton]

If I want to add a "power amp in" 1/4 inch jack on a tube amp and want to be able to use an A/B switch to toggle between the internal preamp and the external one I would plug in that input, how would this need to be executed ?

Thank you!

[hebaton]

No one can help ?
Just wondering If I need to do anything other than beginning the connection to the PI ?

Thanks

[ViperDoc]

One method is to install a passive effects loop right before the input of the PI tube and use the Return jack as the Power Amp Input. What you have to manage is your input to both preamps, perhaps with a AB box before your amp input that's part of your switching system. You will also need to design your power supply to avoid ground loop noise. You could also design a dual preamp circuit of your own inside your chassis. Lots of options.

[sluckey]

I would do it like this...

[hebaton]

In the amp I want to use, there is a tube buffered loop in that position.
Could I still use an AB box there do do that without any issues ?

[hebaton]

ANyone offering a D type preamp ?
:-
)

[ViperDoc]

Or you could do it like this. It's possible you may need a Humdinger somewhere in the preamp pedal loop:

AB Preamps.png

[hebaton]

This doesn't work because the internal pre's sgnal cannot reach being defeated by the loop

[ViperDoc]

You are correct. Then perhaps a pre-loop or pre-master mixer circuit?

[sluckey]

In the amp I want to use, there is a tube buffered loop in that position.
Could I still use an AB box there do do that without any issues ?

Try it and see. How hard is that.