Rect-o-verb Head V2 Parallel to Serial Loop

[ppberube]

Hi,

I found the schematic to modify the loop of my Rectoverb Head V2. I want to use my Boss GT-8 with the 4CM.

So i did the steps (isolated the right wire of the potentiometer and put the left wire on the central pin) ; pretty easy

Something i don't understand though and i hope someone can explain it to me ;

If my loop is serial, why do i still hear sound coming from the amp if nothing is connected in the loop (not even a cable thats goes directly from the return to the send)

Thank you.

 

[ppberube]

If you look at the bottom image, it's like the send / return is directly connected so that could explain why you still get sound.

But at the same, if you plug something in the loop, it would be directly shorted by that wire.

Anybody can explain ?

 

[MikeK]

Hi. I was searching for info on the serial/parallel mod and found this. Thanks it's just what I needed. As far as the question about the noise, I believe it's like that because in serial mode, your effects loop is part of the signal path ALL of the time. It's like having the instrument cord disconnected while the amp is on. You might try a jumper between FX In/out if you want to play with the loop empty.

 

[MusicManJP6]

I never put that much thought into it I just know it makes my delays sound much better!

 

[mr_fender]

It's because Mesa uses switching jacks on the FX loop. When nothing is plugged into the jacks, there are contacts that are closed which hard wire the send and return together. When you plug something into the jacks, these contacts are broken and the signal then goes through the plugs and cables instead. It's quite a clever design actually. Input jacks often work the same way. That way the amp's input gets grounded when nothing is plugged into it. The schematic in the above post is not correct. Here's a pic of the before and after schematics when following the directions in the above post.

 

[JSutter]

Looks like a useful mod. Is there a way to wire it on a switch? That way you can have both?

 

[MusicManJP6]

Looks like a useful mod. Is there a way to wire it on a switch? That way you can have both?

Push/pull pot to replace the mix pot would require the least amount of alterations, but not sure how difficult that would be...