Single Rectifier FX Loop Mod

[sevenfoxes]

Hello everyone! This is my first post, so please go easy on me.

Many of you are aware of the infamous fx loop problem that occurs due to the nature of it being parallel instead of serial. Well, I recently acquired a single rectifier, and couldn't have been happier. That is until I put a tc electronic t2 pedal in the fx loop, and needless to say, the annoying helicopter rumble invited itself to the party.

A google search led me to information on the parallel to serial mod, but the information seems to be somewhat scattered and not very consistent or concrete. Some people say the mod worked without problems and even made their amp sound better, while others complained of tone coloration, volume problems, etc.

My question is for those who have attempted this mod. What was the outcome? Are there downsides? Do things stop working on the amp? Does the tone become altered? Any helpful information that you could include would be incredibly appreciated. Thanks so much!

 

[afu]

https://warpedmusician.wordpress.com/2015/08/27/in-action-dual-rectifier-loop-mod/

That's from my blog. The link in the first paragraph goes to the page describing the mod. I love it. There is always coloration from the loop, regardless of the type, because of the extra tube stages and circuitry. However, this mod made an improvement on the sound and is easier than the other mod.

If you decide to perform it, the layout of the 2 Channel amps is different, so note those differences and apply the concept to that wiring (Wet path to Return stage grid).

Good luck.

 

[sevenfoxes]

For starters, thank you so much for your reply. I was beginning to think this thread was going unnoticed.

Now, I took a look at your pictures and diagram. I think I'm even more confused now, because I see more differences between the single and dual recs then I see similarities, and I think it's throwing me off. Also, I've decided to have a local amp repair tech tackle this. He's never done it before, but he's confident that he can do it, especially If I provide him with documentation. I'm assuming he's much better at soldering than me as well. Anyways...

Is your mod pretty much the same as this one?...

http://forum.grailtone.com/viewtopic.php?f=4&t=26702&start=0

Are there any differences?

Again, thank you!

 

[afu]

It's the same thing. Thanks for the find, btw. I can eventually link to it.

The only differences are:

• I left the wire on lug 1 and taped the end; He left it attached to the board and taped the end. Either way is fine, I guess, but signal goes through the track on mine and I wanted the wire out of it.
  
  His jumper wire is longer and has insulation. I decided to use a shorter, non-looping, jumper to prevent any capacitance, which may create an antenna for signal/noise/whatever. A bare jumper is safe when flush. To me, it's no different than the PCB track.

 

[sevenfoxes]

It's the same thing. Thanks for the find, btw. I can eventually link to it.

The only differences are:

• I left the wire on lug 1 and taped the end; He left it attached to the board and taped the end. Either way is fine, I guess, but signal goes through the track on mine and I wanted the wire out of it.
  
  His jumper wire is longer and has insulation. I decided to use a shorter, non-looping, jumper to prevent any capacitance, which may create an antenna for signal/noise/whatever. A bare jumper is safe when flush. To me, it's no different than the PCB track.

Thanks for your help. I just paid my local amp repair tech $20 to do the mod. He only wanted to charge me $10 because it only took him 5 minutes, but I insisted. It's so nice being able to play my fx at maximum level without phasing issues now. I also don't notice any loss of tone.

Thanks again!

 

[afu]

It's no problem. That's why it's there.

 

[tele twister]

I just started using my FX loop, finally, and discovered that infamous helicopter rumble sound when any one of my three level controls are a little above noon. I use a MXR Carbon Copy delay into a Boss RV 5 reverb, then back to the return.
I have searched and found some mods here; one sketch from a Mesa tech, which is very simple and well within my skill level, and two featuring a series/parallel switch, one claiming the other is wrong.
I am curious as to what is the advantage of being able to switch it back to the stock parallel path, if it creates this rumble. Would just going to a series path only, be the simplest effective way to go :?:

 

[afu]

Parallel works well with rack equipment. Since the Rectos are stage amps and rack systems were popular at one time, the parallel loop would have made good sense for Pro use. While features once only found on rack effects have made their way to floorboard processors, the bulk of them still cause issues with a parallel loop, and the popular 4 cable method has audible comb filtering when used with a parallel loop. However, the right gear works with in parallel. It just depends on how much money you have and what sound you want. I have less money and a want to use a wider variety of things, so I went with a simple serial mod.

 

[tele twister]

Since I don't have a rack thingy, and don't plan on having one anytime soon, (<$,also :lol: ) I'm thinking the mod to series is all I need.
I just want to get a little higher on my pedal levels and that rumble is holding me back.
WTH, Y not :!:

 

[afu]

That's about how I felt. The one wire mod above is reversible. If someone needed to switch back, it wouldn't be much of an issue to spend the few minutes to do so.

 

[tele twister]

Yep, that was easy, I did the simple series mod. I am very pleased with the results and...no more rumble :!:
Thanks for the nudge folks.