Help please? Adding fx loop to amp.

[markeebee]

Slightly late, but......HAPPY NEW YEAR TO ALL!!!

I'm after a bit of advice.  I recently got a Vox AC30VR, which is a kinda hybrid version of an AC30, to save my back from lugging the 'real thing' to rehearsals.

It's not bad at all, but the high-gain settings are just a little fizzy.  So, I'd like to add a 'power amp in' jack, so that I can use different homebrew preamps to see what they sound like.  While I've got the hood up, I guess I might as well add a send/return function.

So, here's something that purports to be the AC30VR schematic:



It looks extremely straightforward at first glance; just add some switching jacks between the preamp out at R16 and power amp in at C93, and tack the grounds of the jacks back to the main ground buss.

But, there's a guy on the Vox forums that makes mod kits, and he's been promising a loop kit for this amp for a while but hasn't managed to come up with anything yet.  So that makes me feel a bit nervous.  Is there something obvious that I'm missing, before I start ripping shizzle apart?

Cheers!

[dwmorrin]

There doesn't seem to be anything wrong with your plan to install a basic send and return.
In some amps, I've noticed the return jacks will have input overvoltage protection diodes.  I was just working on a SVT-3 Pro that had them.  You could check the schematics of that amp or other amps with sends and returns to see what "extra" bits get throw in.
But your plan should work.

[markeebee]

Thanks David.  Worked nicely, don't know why I was concerned.