increased noise in true bypass looper DIY?

[sweethomela8]

I'm trying to understand why I get an increased noise when I turn on my true bypass looper (i have a cable just going from the send to return, no pedal..for testing purposes), when the pedal is off, its quiet, and when the pedal turns on its noticeably noiser, even though the pedal is completely passive (only wires, cable connecting send and return, and a 3pdt switch)...i expect it has something to do with my grounding, but don't know what exactly.

At first, I had a hammond aluminum pedal chassis and i left all the sleeves (ground connections) un soldered, since they were connected together via the chassis. I followed this schematic..

http://www.beavisaudio.com/techpages/PedalHacker/LooperWithLED.gif

I noticed the noise and thought hey, its probably because i have several points where the grounds meet causing ground loops.

On the second run, I decided to not use the chassis and laid everyone out on my desk and connect edall the grounds like the schematic described....same issue....noise when turned on...

I know its not the LED or battery because i disconnected it to make it completely passive and it was still noisy....theres no pedal in the effects send/return...its just a straight guitar cable...short length too...

I dont think the noise is coming from the switch, its completely mechanical...if i had pops then i can see that it can come from the switch...but not an increase in noise level

so now im stuck, wondering maybe if i should do a star grounding connection, where i connect all the grounds from the 4 jacks, the 3pdt, and battery to one spot? running out of ideas...anyone have any thoughts?

[jonathansuhr]

What pedal is in the true bypass loop?

It could be that the buffer from the pedal you are bypassing has actually cleaned up noise, and now when you utilize the true bypass looper, you are removing the buffer, thus adding noise.

If that is not the case, it could be the cables used or a bad ground connection. Check over all your joints and make sure there are no cold solder joints.

[sweethomela8]

Theres no pedal in the bypass, its just a straight cable, i did that to make sure that its not the pedal...so basically its...guitar---->in --->send---monster cable--->return--->out--->amp when the pedal is engaged.

I've ohmed out each of the solder joints, and connections to ground, everything that should be connected to ground is connected.

I can use better cables of course, but with any wires or cables you use, the noise shouldn't increase when the true bypass pedal is on. it may be noiser in general than when you use other cables, but for the same cable setup, the noise should remain the same when the pedal is engaged.

[dangeroso]

Can you post a pic? I just built one myself and had no noise issues.

[sweethomela8]

Heres a picture without the chassis, when its on, theres significantly more noise.

the middle jack is the input, the two above and below it are the send/return, and the jack on the opposite side is the output.

the grounds are currently daisychained...starting at the sleeve of the input to the sleeve of the send to the sleeve of the return to the sleeve of the output.

the sleeve of the output is also where the battery ground and the connection to the 3pdt switch are grounded.

http://i54.tinypic.com/ny767q.jpg

[sweethomela8]

has anyone tried daisy chaining the grounds vs doing a star pattern ground and connecting it to the chassis?

[mcdes]

has anyone tried daisy chaining the grounds vs doing a star pattern ground and connecting it to the chassis?

when i build mine, i only connect the ground where needed.... so instead of wires between all send/returns etc, the metal chasis is gounded, and links them all that way, less wires, less soldering, less hassle.

[mcdes]

to the OP, have you got a close up on the switch connections by any chance? with indications of where they go ..... maybe just a back shot.

[sweethomela8]

yeah originally when i built mine i also had the ground through the chassis like you mentioned...same noise issue. Have you tried just connecting a cable between the send and return lines and see if the noise goes up on yours?

Here's a pic of the one that I made before that has the grounding through the chassis....keep in mind i clipped two of the wires in the pic so just pretend they are connected.

http://i52.tinypic.com/30c4pc7.jpg

[mcdes]

i never had any hum issues eitherway. i take it it still has issues when you removed the wiring harness and tried it???

looks pretty tight in there, make sure nothing shorts out, specially when plugs are inserted, and the connections are solid.

[sweethomela8]

Yeah no shorts in there, I ohmed and buzzed everything out with an DMM, and yes the buzz is still there when I remove the chassis (see the first picture). So you didn't wire up the grounds at all? You just connected the jacks to the chassis like I did in the second picture?

[stinkfoot]

One of the jacks needs to have a ground wire, to run a ground line to the switch. But other than that, the jacks' grounds will be connected through the box, yes.

It is a bit hard to see in the pic, but what's connected to the middle/middle lug on the switch? It should be the main output wire, but it almost looks like that wire is going to the middle/right (ground) lug. That said, if that were true you'd get no sound in either switch position, so that's probably not it...

[sweethomela8]

Yes, the middle/middle lug is going to the output tip and yes in the second picture, where the grounds are connected through the chassis, the right most middle lug is connected to the ground sleeve of the output (lower right) jack.

Looks like this is really a mystery, I may have to try using really good insulated short (as possible) wires, try doing a star ground type connection to the chassis in one spot and isolate the 4 jacks from the chassis.

Anyone have good recommendations on what type of wire to use (low capacitance, etc) or have any experience with good results after doing a star grounding scheme (running all the grounds from the 4 jacks, battery ground, and switch ground, to one spot on the chassis and soldering all of them there ...should look like a star formation)?

[mcdes]

you could always just pull it all apart and start again??? haha, you may find/fix it.......

[sweethomela8]

haha, yeah im on the third unit and they all act exactly the same, so i know it has to do with the design in some way....i need to try that star grounding/jack isolation from the chassis....but its so painful! =/

[this1smyne]

i don't think you need to star ground..... i've built hundreds and hundreds of loopers and never had this issue... is the power bad in the room you're testing it in? is the power supply you're using for the LED regulated? cables between the pedal in the loop? honestly, these are pretty simple to build.... check your solder joints too.... make sure everything is good and melted in there.

star ground probably never has to be used in a pedal. thats for amps and jank.

[sweethomela8]

hmm, so in your builds did you ground it through the chassis and only solder one ground wire from a jack to the 3pdt switch? I've ohmed out every ground, and is it true that if I had a cold solder joint, it wouldn't see a short, but infinite resistance (open circuit)? Power may be bad in the room I'm in, but I wouldn't think that would increase the noise when the pedal is on. I can believe the general noise of my amp/system is louder than normal, but i wouldnt expect an increase with the pedal on (especially if its all passive components). I've disconnected the battery also to see if that was an issue...it was still noise increase seen, so I know its not from the battery/LED...out of ideas...thats why its so frustrating! thanks though

[this1smyne]

i almost always only have 1 ground point, from the power supply to the ring on the input, so when you plug in you make ground, all jacks share chassis ground. not just loopers, but all the AB's, drives, everything.... there is definitely something amuck. it could very well be the switch (i know the pots are prone to melting if overheated) as thats the only moving part in the build.

[sweethomela8]

So, on your pedals that you work on, do you connect everything to the chassis by using wire? or does that connection happen only at the washer at the audio jacket? What type of wire or wire gauge do you typically use?