Shoot The Moon Tremolo

[Kinski]

Built this and it sounds great. However, I get a huge pop when turning on/off. Also, when turned on, I get a loud thud that pulses in time with the LFO then slowly fades. I added a 1m resistor from the circuit output lug on the switch to ground. Also, replaced both in and out caps. No help. This happened with the heartthrob pedal I built as well. Never could fix it. Any ideas? I'd really love a trem that does not have these issues!

I'd love some help!

Layout (I used the 4-knob version):
http://tagboardeffects.blogspot.com/2013/04/culturejam-shoot-moon.html

[Frank_NH]

What does your off-board wiring look like?  Are you grounding the vero board input and output when in the bypass mode?

I have built and boxed a Heartthrob Tremolo and don't have any popping issue.

[Kinski]

Thanks for the help!

I use this:

[Kinski]

I don't have really have popping issues with my builds, except when I try to make tremolos. Its weird.

[Frank_NH]

That one grounds the input but not the output.  If you wanted to experiment, you could take your output wire from the board off the switch and attach an alligator clip to it.  Attached the other end to a ground point.  Switch the unit off.  Switch it back on.  Take the grounded output and now attach it to the output jack.  Does it pop?  I think the idea with grounding during bypass is to drain the charge from the capacitors (1 uF in this case) before the effect is re-engaged.  Let us know what you find.  

[Ciaran Haslett]

I had fierce popping with my Hearthrob trem so I tacked 2 1meg resistors on the switch for board input and output.  Completely solved mine.  

I used Kosts second layout here

[Kinski]

Thanks all for your help! Well, I don't know whats up.

I replaced all capacitors and put pulldown resistors on the input and output switch lugs. Still pops just as much. The first few on/off switches are so loud. Then it slowly decreases until switching is completely silent.

I tried adding a simple JFET buffer to the in and output, and that offered no improvement either.

Grounding the output after powering up the circuit DOES get rid of the pop for the most part, but it must be connected to ground for a good while. If you just connect it to ground for a quick second or 2, the pop is still loud. It must be grounded for much longer than that to get rid of the pop.

WTF?

[nocentelli]

That layout has no output pull-down resistor. You mentioned a few posts back putting a 1M on the switch from output to ground, I'd suggest 10x smaller, i.e. using a 100k pull-down resistor on the output. I build that vero with an added 100k pulldown on the output and it doesn't pop. Hope this helps.

[Kinski]

nocentelli, you are my hero. I never heard of using any value smaller than 1m for a pulldown, so I never even thought to try it. The 100k did it! I'd buy you a beer if i could!

[nocentelli]

1M or higher for input, 100k or even lower for output is the general rule of thumb. I think you want the input impedance high so it doesn't load down the guitar, but output impedance needs to be low to avoid loading the input of the next effect. Most volume pots are 100k, so a 100k pull down replicates this if there is no pot.

[Kinski]

Good to know this!