Hey Dave! Effects loop question.

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Enjolras56

Enjolras56

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Hi Dave,

I noticed on one of your boards in the past, you made the FX loop pedals 'optional' in case the player wanted to put everything up front. (Devin Bronson's board?)

How do you approach this on a Trailer Trash-style board? Is it just a matter of placing a short cable between FX send and return, then using the out from the last pedal in the chain? I don't recall seeing an "Interface" kind of box underneath that board.

Thanks! You rock!
 
You can do it with normaling jacks. There is a out the normals to the snd jack. You use the rtn jack if you want everything in front of the amp and the out if not. Works just like a interface would.
 
Hey again Dave!

I was hoping you could help troubleshoot a prob I'm having with my fx loop.
I'm running MXR smart gate>Morley volume>boss dd20>Ehx nano holy grail in the loop. Bunch of pedals on front of the amp all powered by MXR/CAE mc403 power supply.

Lately, when I kick in either the reverb or delay, I'll get a hi pitched whistling/ feedback tone creeping in whether I'm playIng or not. It progressively gets louder and stops once I bypass the pedals. Doesnt happen with any other pedals in front.

I've read that it could be either a microphonic Preamp tube in my amp or possibly a power supply issue? Was hoping to get your thoughts.

Thanks!
 
What you get is related to a grpund loop problem. It happens with some amps when your "front" pedals share the ground with the "loop" pedals. Happend to me at least twice, with different setups.
First thing you should do is get separate power supplies for the two chains. Second, if that doesn't help, is to get an Ebtech Hum eliminator, and place it between the amp's send and the input of the first pedal that is placed in the loop.
 
Thanks for your input dass101
That does make sense as it has happened with two separate amp heads and that it doesn't happen all the time.

Would be a bitch to get separate power supplies right now, but will consider the hum eliminator.
Dave (or anyone else for that matter), if this is what's happening, would it help to ground a wire to the board itself? (Trailer Trash board)
Where does that wire come off of?
I noticed that in another thread(the recent wet/dry board), which I failed to do on mine.
 
That won't help, what you want to do is break the ground circuit. Imagine it like this, your ground goes through all your pedals, even if they are in front or in the loop, because of the power supply that connects all of them. Now, besides that ground circuit, there is a ground connection that goes through the amp. You now have a ground loop, that needs to be broken. You can do this in any of the ways that I mentioned before. The separate power supply is the easiest solution, this is common sense when having a rig like that. Even better, get one isolated power supply for all your pedals. These work like completely separated power supplies at each output, and will save you from a lot of troubles. Voodoo Labs, G-Lab (the ones that Dave seems to favour), Cioks (I have these, they are great), just look for isolated outputs. Some PS have two isolated sections, each section with a few outputs. This also works, just use each section for each bunch of pedals.
The phenomenon that you describe also happens whan using some effects in 4CM, thus connectig them at the same time in the front and in the loops. The ones that are designed good don't share the ground between their outputs, specifficaly to avoid that, some cheaper ones need to be used with a Hum Eliminator.
 
The MXR/CAE mc403 power supply has the isolated outputs:/
 
The MXR is a isolated supply. Make sure the front end pedals and the back end pedals are not touching each other at all because that will give you a ground loop. Also is there any interface box on the board? or what kind of board do you have?
 
It's a Trailer Trash board, no interface box,no pedals touching.
Will that grounding wire to the board chassis help?
 
What jacks do you have mounted to the board? what kind?
 
Switchcraft model 11.
1 input, main out, fx loop send and return, and an extra jack for my Ho Attenuator footswitch.
 
Thats where the ground loops are. All jacks need to be isolated accept the input. You have one ground path and thats causing the problem.
 
Cool, so is it that the #11 jacks don't isolate? Switch 'em out for a different kind?
Btw, your time and knowledge is incredibly appreciated!
 
Yes switch them out. Go to mouser electronics Mouser.com and get this part #568-NYS212. You should put these on all but the input jack. Keep the input the switchcraft.
 
Awesome Dave, Thanks.
Last question, will this jack work as a normalling jack?
If not, which ones do you use for that? (To make the effects loop optional.)
 
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