Please help with a switch popping problem on my multieffect (pics included)

[jasonsmusicgear]

My multi effect unit works great except that it has switch popping problems on every effect.  All the circuits work as they should and do not have any unwanted noise.  I used shielded cables on the ins and outs and star grounding to try to keep the noise down.

Here's the things I have tried:
I disconnected one of the leds to see if that's the problem but there is still popping on that effect, I did not try it on any of the others. 

I also checked for DC on all the inputs and outputs.  In a lot of posts about switch popping I see a common theme from R.G. about having DC on the input or output of the circuit because of leaky caps but I get 0.000v on every circuit. 

Here is a picture of the effect

Here is a picture of the guts


Here is the order of effects:
TS808 #1
TS808 #2
EA Tremolo
Phase 90
(TS808 #3 & PT80 in effects loop)
LPB2
Guitar A/B switch
Tuner
Condor Cabinet Simulator

All of the effects were built using schematics and layouts from www.generalguitargadgets.com except for the condor cabsim which was built from http://runoffgroove.com/condor.html

Could I have an overall problem with my power or ground?  All power is daisy chained from the built in power supply at 9v.

Thanks for any advice that can be offered.

Jason

[Bad Chizzle]

Don't know about the popping, but....... That things awesome!

Sweet build, buddy

[FlyingZ]

If one is still connected while bypassed like trails on a delay they all will pop. First discovered that with a DD-5 in a relay loop.

I also had a poor power connection on a chip (forgot to solder) that caused the switch to pop.

[jasonsmusicgear]

If one is still connected while bypassed like trails on a delay they all will pop. First discovered that with a DD-5 in a relay loop.

I used the 3pdt wiring scheme that grounds the input on everything except the looper, shouldn't this solve the problem of still being connected while bypassed?  Maybe the looper is the problem?

[mrscientificterms]

Totally of topic, but I agree the above poster, that is a really super cool build (has my mind flying and wondering what I have stashed away parts-wise).  Hope this comes together for you.  When it does an on-line demo would be very cool.  cheers!

[Thomeeque]

 My experience is that mechanical true-bypass switch simply generates some pop (even very silent, but still noticable e.g. when using delay) no metter how hard you try to avoid it, as a result of transient performance on contacts.

If you have no DC on in&out's and LED switching is not causing this as well, it's probably as good as it gets.

Well, you can still try another type/brand of switches or some contact cleaner on present ones maybe, but I don't know..

T.

Edit: I have forgot to mention that I like your build too

[jasonsmusicgear]

Thanks for all the replies and all the compliments.  I'm thinking my next move will be to put the PT80 on a separate power supply because my other PT80 has had strange interactions with pedals on my other board in the past.

Another strange thing with this effect is that if you tap on some of the input and output wires that are shielded they will give an audible pop through the amp at higher volumes.  I also get some audible noise when depressing the plunger even before it clicks into place.  Does this open up any other possibilities or is this normal?

I only grounded one end of most of the shielded wire to avoid ground loops, but there were a few places where I used the ground in the shielded wire to run ground to something else.  Could I have a ground loop somewhere causing this?

Thanks again
Jason

[Joe Kramer]

You didn't say anything about pull-down resistors.  Do you have them in place?  There should be something like a 1M before the input cap and about 100k after the output cap of every single effect.  If the input and output caps are left hanging in space when the effect is bypassed, they build up DC charges, which cause the pop; the resistors drain away DC charges from the input/output caps.

Another possibility is that you have too much gain going on with all those TS-808s.  Having high gain pedals linked together and running at the same time can make switches, wire, boxes all microphonic.  Not much help for that except to use soft stranded wire, and keep it loosely bundled and away from the contact with the enclosure.

[jasonsmusicgear]

You didn't say anything about pull-down resistors.  Do you have them in place?

I'm pretty sure that everything has pulldown resistors except for the PT80.  Could this still be a problem even if I measured 0 volts of DC at the inputs and outputs of everything?

Another possibility is that you have too much gain going on with all those TS-808s.  Having high gain pedals linked together and running at the same time can make switches, wire, boxes all microphonic.

Are you saying that even when the TS-808s are bypassed they can cause this problem?

Thanks for your help
Jason

[Joe Kramer]

I'm pretty sure that everything has pulldown resistors except for the PT80.  Could this still be a problem even if I measured 0 volts of DC at the inputs and outputs of everything?

Well, it only takes a millivolt to cause a pop.  But I guess you can rule that out if you're sure it's not a DC/pulldown resistor issue.

Another possibility is that you have too much gain going on with all those TS-808s.  Having high gain pedals linked together and running at the same time can make switches, wire, boxes all microphonic.

Are you saying that even when the TS-808s are bypassed they can cause this problem?

I don't know, I've seen original old TS-808s with flip-flop switching do this when the gain is set high.  In that case, I think the circuit was feeding back on itself for a split-second during switching.  Depending on the switches you're using and how they're wired, that sort of internal feedback could cause a pop.  You could check if they still pop when the gain is set low.

Another thought: are you using your multieffects with a tube amp?  If so, a bad input preamp tube can cause a pop with effects that otherwise don't pop.  Verify that you're still getting a pop with some other amp as well.

BTW, very cool unit you put together there!   Hope you sort out the trouble.

[Gurner]

You didn't say anything about pull-down resistors.  Do you have them in place?

I'm pretty sure that everything has pulldown resistors except for the PT80.  Could this still be a problem even if I measured 0 volts of DC at the inputs and outputs of everything?

The DC pop you refer to needn't just be from DC present at the input/output, but can also be from rapid changes in DC within the circuit itself when power is first applied/removed - are all those effects powered up all the time? (from the red wires from your PSU to each footswitch I'd hazard a guess & say not - if that's the case, then I'd say you've got a job on your hands attacking each circuit in turn with workarounds to silence when enabled - personally, I'd just ensure that power is on to them all the time (and simply switch the signal into each circuit's input with the corresponding footswitch) - that's not gonna help the glazial ice caps, but should help with popping.

[jasonsmusicgear]

I don't know, I've seen original old TS-808s with flip-flop switching do this when the gain is set high.  In that case, I think the circuit was feeding back on itself for a split-second during switching.  Depending on the switches you're using and how they're wired, that sort of internal feedback could cause a pop.  You could check if they still pop when the gain is set low.

I have two of the TS808s set to max gain and the third set to about 3/4.  I forgot to mention that all the TS808s are modded to Keeley's mods to have a little more gain.  I will try turning them down tonight and see what happens.

Another thought: are you using your multieffects with a tube amp?  If so, a bad input preamp tube can cause a pop with effects that otherwise don't pop.  Verify that you're still getting a pop with some other amp as well.

BTW, very cool unit you put together there!   Hope you sort out the trouble.

I have tried the effect with a Fender Super 112, a Fender Twin Reverb, and straight to the PA using the Condor cabsim and I get the pop on all three.  Thanks for the compliment and all the help.

are all those effects powered up all the time? (from the red wires from your PSU to each footswitch I'd hazard a guess & say not -

Yes all the effects are powered all the time.  There is one red wire running to the board that powers all the effects and the other red wires are just powering a few of the LEDs that did not have a resistor already included on the board.

Thanks for all the help
Jason

[jasonsmusicgear]

Well I tried turning the gain to 0 on all the TS808s and the Condor last night.  It does reduce the pop some but it is still noticeable.  It seems like the pops are the worst when using the Condor cabsim.


I have seen a couple comments about the poor quality of the white 3pdts.  Could they really be that much worse than other 3pdts?  Has anyone else had problems with the white 3pdts?

Thanks

Jason