|HOME| |DIY FAQ| |GEO FAQ| |Debugging Page| |Links| |Schematics| |Wiki| |Layouts Gallery| |STORE|
|AMPAGE| |GEOFEX| |AMZ|

Welcome, Guest. Please login or register.
Did you miss your activation email?
August 29, 2014, 12:15:10 PM
965025 Posts in 103059 Topics by 32658 Members
Latest Member: h3n
Home Help Login Register
DIYstompboxes.com  |  DIY Stompboxes  |  Building your own stompbox  |  TB dual looper and bleed noise. Isolated ground problem? 0 Members and 1 Guest are viewing this topic. « previous next »
Pages: [1] Go Down Print
Author Topic: TB dual looper and bleed noise. Isolated ground problem?  (Read 1012 times)
pedrohead
Posts: 2


TB dual looper and bleed noise. Isolated ground problem?
« on: March 28, 2012, 04:46:43 PM »

Question for you guys.

I had a dual looper pedal built for me (A/B between two sets of loops, I use one for my buffered pedals, and one for a fuzz that doesn't play well with them), and when I'm in the "buffered pedal" loop, I have bad bleedhrough "hum" noise coming from the "bypassed" fuzz loop. If I toggle that fuzz pedal off, it goes away, but also defeats the purpose of the pedal (just hitting one button to swap between the buffered pedal and onto that fuzz). I was poking around and noticed that all the jacks' grounds are wired together, going to the center hub on the 3PDT switch, but also wired to the PS negative jack as well. I checked all the other connections and nothing's loose or grounding out on its own.

Is it potentially the problem that the PS/jacks/LEDs are all sharing a common ground? Would I be better off separating the jacks' grounds and the LED/switch/PS ground?

Thanks.

Here's a pic. You can't really see where the traces are going, but get a general layout understanding.

http://img.photobucket.com/albums/v388/pedrohead/photo3.jpg
Logged
Processaurus
Posts: 2962

Ben Milner


WWW
Re: TB dual looper and bleed noise. Isolated ground problem?
« Reply #1 on: March 28, 2012, 05:36:22 PM »

It is more likely a problem of the fuzz oscillating when it is bypassed, because its input is left floating by the true bypass looper.  Grounding the input of the fuzz when it is bypassed (with the throw of the switch also used for the LED) should stop it from feeding back on itself.
Logged
pedrohead
Posts: 2


Re: TB dual looper and bleed noise. Isolated ground problem?
« Reply #2 on: March 28, 2012, 05:51:35 PM »

It is more likely a problem of the fuzz oscillating when it is bypassed, because its input is left floating by the true bypass looper.  Grounding the input of the fuzz when it is bypassed (with the throw of the switch also used for the LED) should stop it from feeding back on itself.

I think that's exactly what I need to do, I just can't figure out in my head how to accomplish that with the switch (it seems like all the throws are taken up with having to account for the two individual loops send/returns/LEDs and the in/out of the box).

The 9 pegs of the 3PDT are set up in this fashion:

1.Return B           2. LED gnd B        3. Send B
4.Out                  5. Ground            6. In
7.Return A          8. LED gnd A        9. Send A

What would you propose connecting in order to add that functionality? In just poking around with a piece of wire to try different combinations, anything that grounds the A loop while B is playing, also shorts out the signal when A is playing.

Thanks.
Logged
Processaurus
Posts: 2962

Ben Milner


WWW
Re: TB dual looper and bleed noise. Isolated ground problem?
« Reply #3 on: April 20, 2012, 03:26:42 AM »

The simplest thing would be to lose an LED, say lose [LED gnd A] and connect that throw of the switch to [Send A].  Put the Fuzz in the A loop.
Logged
Pages: [1] Go Up Print 
« previous next »
Jump to: