Modded triple rectifier fx loop

[goatermeister]

Just got my 2003 triple rectifier loop modded from parralel to deries, but have some questions...

First, I read many times that by doing this mod, it would defeat the solo ad output controls. Mine in fact still work. The send fx loop control now acts like a volume adjustment, ad the mix control is inoperable. Also, I have to have a connection in fx loop at all times, otherwise, only a very low volume of sound comes from the amp.

My tech got the wiring diagrams for this mod directly from mesa...

Should there be any sound coming from amp at allwithout cables connected to loop? Should output and solo controls still be active?

I washoping this mod would help overall tone as well... amp sounds way better with loop bypassed, but I rely on delay, flange, and chorus needed in loop, bc it sounds like crap in front of amp....

 

[Mile High Effects]

So you have to have a cable connected for it to work? Then, he did it the easy way and not using a shunting mono jack for the return jack and a link between jacks when fx loop not in use.

I also have a theory that I can’t believe no one has posed: using a no-load pot to take out all 100% of the dry signal when the Mix pot is turned to 100% wet. I’ll be tinkering with that theory later today.

Either way, you shouldn’t need to use a cable to link the jacks. That’s just poor tech work. And the Mesa instructions say to do this:

Converting ORIGINAL 2 Channel Rectifier/Trem-O-verb parallel FX Loop to a Series FX Loop.

Parts needed: 1 pc. #12A or 112A Switchcraft ¼ inch jack.

1. Remove effects "Return" jack and the orange 2-inch wire connecting it to the "Blend" POT.
2. Install the 12A or 112A jack (mono jack with shunting) in the "Return" position, very securely with a lock-washer inside as it was previously.
3. Move red wire from "Blend" POT to tip connection of the new "Return" jack.
4. Add jumper wire from "Send" jack at the Brown wire (tip connection) to switched contact connection of the new "Return" jack.
5. Make sure "normalling" contact on new "Return" jack works well when plug is removed.

 

[TRENCHLORD]

Yes the above post is correct. If done properly you will have full signal even with no cable/pedals in the loop.
You should still have full function of the loop's rotary selections on back, and also normal function of footswitching.
The effects send always is an additional volume control, unless you set the rotary control to "loop bypass".

If you do run pedals in the loop, especially with longer cabling to and from, then you will want an always-on buffer or a pedal with an always-on buffer as the last thing in the chain before the cable returning to the loop. 200ma or less is a good rating for a buffers output stage. Higher than that and you will get some loss of signal. Boss pedals have output buffers of 1kohm for reference. That is 5 rimes higher than you want.

 

[Mile High Effects]

Yeah, the no load pot trick wouldn’t work on the loop. It would remove the wet signal instead of the dry signal.

I’ll upload a pic of the serial loop mod I did yesterday. I forgot to take a pic when I did it so I’ll have to open the amp back up.

 

[FlubbyRec]

I just did the mod, following the directions from Mesa, to my 90's Trem-O-Verb and my neighbors 2-channel Triple Rec. It worked as expected on my amp, but his Triple still has a parallel path somewhere. I just tested them both by plugging an empty plug into the "return" jack on both amps (one at a time)...with the loop active, mine did not pass sound (which makes sense because the shunt is open) but his still has a path somewhere.

I'll get back into it tonight to make sure the jack is working properly, but otherwise...?
Does anyone have a schematic for the 2-channel Triple rev G? I have a dual rec schem, but there are definitely some parts that do not match the triple.

 

[domct203]

It could just be cross-talk between the triodes of the FX Loop driver tube, as they are in the same glass envelope. Try some other 12AX7’s in that spot.

Dom

 

[FlubbyRec]

It could just be cross-talk between the triodes of the FX Loop driver tube, as they are in the same glass envelope. Try some other 12AX7’s in that spot.

Dom

Thanks, I’ll give it a shot. This is full volume, not what I’d expect from cross talk

 

[Mile High Effects]

This is what a proper conversion should look like if you want it to look stock. Switchcraft 112A jack and this configuration.

PS - I got rid of that solder blob after this pic.