Your Source for DIY Pedal PCBs and NostalgiTone! › GuitarPCB Forum › General DIY Pedal Discussion › 3 way loop pedal
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Anonymous.
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July 21, 2019 at 9:26 am #6424
Anonymous
InactiveGreetings!
I made a 3 loop effects strip, however my strip is not working great. A quick description though. 3 loops, each with 3pdt switches. I used this wiring diagram (http://tagboardeffects.blogspot.com/2012/07/true-bypass-looper-5-loops.html). I added a 9v input jack which I daisy chained to three other 9v jacks to provide some power distribution (9v input is connected to a PS to the 9v 200ma output). Each of the 3pdt switches is grounded to the receive ring of it’s own loop. LED 9v is chained along the 9v jacks, and led ground connected to the switch.
It all works – no hums or buzzes, but… using loops 2 & 3 with a single fx pedal on each, they rob each other of signal. Which I don’t understand. Anyway the diagram i used has a buffer circuit added, so I thought that would help.
I built a buffer, added it in front of the chain, again no hums or buzzes, but whoa – did it POP when engaging any of the three switches. I tried putting it at the end of the chain, same thing.
I added a 1M resistor to the ground from the buffer and also to the 9v jack chain, and 1M between the tip and ring of both the input and output jacks.
Still pops! I’m new at this, doing the best I can, but I am stumped here. Any thoughts that might help me?
July 21, 2019 at 7:53 pm #6432wilkie1
SpectatorAre you using GPCB 3PDT wiring boards to facilitate construction of your looper pedal? Without a complete wiring diagram of your build, I cannot tell you where to look for an error.
July 21, 2019 at 8:20 pm #6433Anonymous
InactiveThanks Wilkie, I am not using GPCB 3PDT. The diagram I used is this:
http://tagboardeffects.blogspot.com/2012/07/true-bypass-looper-5-loops.html
I just added the 9v jacks.
July 21, 2019 at 8:35 pm #6435Anonymous
InactiveI omitted the tuner jack, the buffer and the buffer switch. But the loops would sap the signal when engaged, so I tried adding the buffer which is when I started getting the POPs.
pg
July 22, 2019 at 12:46 pm #6436wilkie1
SpectatorSince you have made substantial changes to the schematic you have published, I cannot tell you where there is an error. You will need to give us clear detailed photos with voltage measurements at critical points. Also provide a drawn schematic of your build so we can tell what you have changed.
You are working from a design that is not a GPCB product. The popping you are experiencing may be caused by voltage appearing in the signal path. Without the tools requested, I cannot further assist you.
July 22, 2019 at 8:01 pm #6439Anonymous
InactiveHi Wilkie,
I completely understand, I thought this was a general forum and not restricted to GPCB products. Thanks for your comments, it gives me a lead 🙂
smile, pg
July 22, 2019 at 10:19 pm #6441wilkie1
SpectatorYes, we will offer assistance for other projects as long as we are given enough information. I am here to help if possible.
July 23, 2019 at 8:01 am #6445Anonymous
InactiveFair enough, I appreciate the advice.
Anyway the answer is – 1M pulldown resistors to ground tapped into the audio signal into and out of the buffer. http://www.muzique.com/news/pulldown-resistors/
Since I have no good technique to do that it’s mighty ugly, but it works, no pops, and the buffer keeps the signal steady.
Looking forward to the new pcb’s – blues buster and ancestral apparition!!
thanks, pg
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