Fender reverb send/return as effects loop?

[mike_mccue]

Hi,
A friend recently suggested that I try the reverb send/return on my 1979 Fender Deluxe Reverb as an effects loop.

My first thought was about the impedance bridging. How can I quantify the output impedance of the reverb send and the returns input impedance?

thanks,
mike

edit to add... I'm not real interested in an effects loop... I'm more interested in thinking about how the existing impedances would effect the circumstance.

[Don Moose]

The reverb transformer expects to be driving something in the neighborhood of 8-10 ohms (some little amps use it as an OT) with roughly a watt. You'd almost need a dummy load and a good DI box with some EQ.

It wouldn't hurt to add a diode clamp from the first FX's input to it's (+) rail and either GND or the (-) rail - whichever it has, just to be safe.

Hope this helps!

[mike_mccue]

Hi Don,
That's kinda what I was thinking.

How about the return? It's just the plate of a 12AX7 so that would be a good match right?

thanks,
mike

[Gtr_tech]

The reverb transformer expects to be driving something in the neighborhood of 8-10 ohms (some little amps use it as an OT) with roughly a watt. You'd almost need a dummy load and a good DI box with some EQ.

It wouldn't hurt to add a diode clamp from the first FX's input to it's (+) rail and either GND or the (-) rail - whichever it has, just to be safe.

Hope this helps!

And it will be bandwidth limited so the rev pan can cope with it without tossing the springs all over the place. I wouldn't bother.....

[mike_mccue]

I agree it's a bad idea. I was trying to learn enough about the possibility to explain to my friend why his suggestion is a bad idea.

I knew it was inappropriate but needed to reacquaint myself with the facts so that I could explain it in a credible manner.

The bandpass filtering is something I had not thought about. Thanks for the suggestion.

best regards,
mike

[52 Bill]

Twenty years or so ago, there was a product on the market called the Mender 2, which was an FX loop add on box that plugged into the reverb loop on Fender amps. It was solid state, powered by a 9 volt and created an FX loop which you could blend in with the original reverb. Maybe there's more info out there on the web.

It was designed and marketed by David Hicks who used to write for GP. His first product the Mender, which added overdrive/channel switching to Fender amps was quite good for a non-invasive mod.

[Don Moose]

How about the return? It's just the plate of a 12AX7 so that would be a good match right?

Well, it's the grid - super-high impedance. Really high gain, too - you'd need to turn the FX output almost off in order not to overdrive it.

The upshot is that it could be done, but you'd do a lot better to install a proper loop - they can be pretty simple, just a pre-out/poweramp-in.

[mike_mccue]

The grid, yes of course. Thanks Don.

Thanks for the further explanation.

best,
mike

[63superreverb]

I know this is an old thread but for future reference...David Hicks posts at Ampgarage.com forum under ampdoc, Smart guy and good amp tec.