Buffer circuit "blanket on the amp" sound

Started by strings4v, June 04, 2016, 03:15:06 PM

Previous topic - Next topic

strings4v

So I have built this pedalboard interface box with a buffer circuit built in. The buffer is Pete Cornish circuit I got off of internet. Previously, it was just a in-out interface with a buffer in between. Buffer worked perfectly. Now I've added a toggle switch, an XLR, and a TRS to allow my MIDI switcher (musicomlab) to control my amp. Since the XLR part and the guitar in-out are separate, I Put electrical tape underneath the TS input and output jack to separate the ground from the XLR part (inside the chassis is not insulated, also I'm not sure if the shielding was necessary but did it anyways) and now I get a muddy signal... Any help would be very appreciated!


PRR

Welcome.

> I Put electrical tape underneath the TS input and output jack

Take that out.

#1) The audio circuit should bond to case. I don't know why tape would make it "muddy", but it is a fairly simple thing to try.

#2) Electric tape will not hold-up as a jack insulator. There are plastic or fiber washers which work much better; also Marshall-style plastic jacks where the sleeve does not touch the chassis.
  • SUPPORTER

strings4v

Quote from: PRR on June 05, 2016, 12:59:31 AM
Welcome.

> I Put electrical tape underneath the TS input and output jack

Take that out.

#1) The audio circuit should bond to case. I don't know why tape would make it "muddy", but it is a fairly simple thing to try.

#2) Electric tape will not hold-up as a jack insulator. There are plastic or fiber washers which work much better; also Marshall-style plastic jacks where the sleeve does not touch the chassis.

Hi, I certainly will!

The problem happened before I put the tape though... I doubt that tape is the culprit.
Without the tape, it makes a click noise when I switch channels on amp via Musicomlab switcher. I will take them off and use plastic washers!

GibsonGM

You probably need to start removing your mods 1 by 1.  XLR first. Switch....until it works.    If you can post voltages and a schematic, please do!  Without those 2 things, we are firing arrows in the dark.
Could be as simple as something mis-wired...or a component in backwards or crossed to something it should not...
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...