I have a mid-seventies Fender Pro Reverb, and I had read once that a person could plug into one input of the normal channel, and then run a speaker cable out of the second input, into one of the inputs on the vibrato channel.  The idea being that you can produce more gain.  I have read of similar things before, but I wanted to check with knowledgeable folks before I fry my amp (and myself).

I've been doing that for 35 years,  I used to do it to my Showman back in the day and have been doing that to my  F2-B ever since. It really fattens the sound. Not a dumb question.
Kenn

Let me get this straight, are you guys saying that the #2 input on the non-vibrato channel doubles as a pre-amp out?  I once wired my champ so that the #2 input was, in fact, a pre-amp out so I could use it in front of a big amp, but this took cracking it open and resoldering some wires - and then it no longer worked as an input (I assumed). I'm finding it difficult to understand how the input can simultaneously be an output too.  Is this really accurate?  And if it is, shouldn't the patch cord be an instrument cable (shielded), rather than a speaker cable (unshielded)?  As for the F2-B, I've heard of (and tried) patching the OUTPUT of channel A (from the back of the unit) to the input of channel B, but I've never heard of stringing the INPUT of channel A to the input of channel B.
 
Bill, tgo
 
(Message edited by lbpesq on May 21, 2009)

I think what's going on is that you're ganging both preamps in parallel, thus providing more gain..

Actually Bill the 2 inputs I believe on BOTH channels are wired parrallel. So basically patching from #2 input of channel 1 to either input of channel 2 would be the same as using a Y cable form your guitar. But you are right, use an instrument cable NOT a speaker cable.
 
The yellow indicates parrallel connecters.

I used to run my Twin like this. And John is correct, you're utilizing both preamps this way.  
 
OO

I have a 2008 '59 Bassman reissue and the quick set-up card depicts the same thing. The amp's goodie pack even came with the 6 patch cable to boot.  Totally different sound when both channels are used.
 
Ellery (Lowlife)

So this is using the two channels independently at the same time, not ganging channel 1 though channel two?  In such a case, a different tone might be realized, but there would be no increase in gain, correct?
 
Bill, tgo

Okay so one more question, does the volume control for the Vibrato channel set the overall volume in this setup, or are the volumes of the two channels independent?  I thought that an instrument cable seemed like a better choice, but the post I read specifically said speaker cable, so I wanted to be sure.
 
Thanks for the replies everyone, I should be getting some tubes in the mail (maybe today), and I'm really looking forward to giving this a shot.  I was afraid that this question was so obvious that everyone would think I was an idiot (now everyone will just have to find another reason ).

Well if both channels have their own tube or preamp you probably will get some extra gain. And both volume controls did work independently of one another.
 
I used to set channel one clean and over drive channel two and use their own volume controls to blend the 2. Made for some cool sounds, a,most like 2 guitars at once.
 
You are correct Bill, it is using the channels simultaneously all at once!
 
OO

Kevin, a speaker cable will work and won't hurt a thing, as far as I know, BUT you will get some serious noise and RF interference.  
 
OO

That's kind of what I thought.  Thanks again.

I had a chance just briefly to try this out when I got home (my tubes had arrived), and I am really liking it.  Thanks again for the help.  By the way, I know other people have raved about Eurotubes.com here, but let me just add another positive endorsement.

I recall back in the days when the backline had to push the stage sound to the back of the room seeing guys with multiple amps doing this, then chaining the other Channel 2 input into the second amp, which was also chained channel-to-channel (and so on for as many amps as you want.)
 
Peter

A famous old thing with multiple Marshall amps!