Click-Less True Bypass Looper - Popping

[Roctopus]

Hey gang,

So I just posted a build pic of a 5 channel "click-less" true bypass relay looper. I used the relay kit from Mammoth Electronics http://www.mammothelectronics.com/Click-Less-True-Bypass-Relay-Module-Kit-p/035-cltba.htm
I also added a trim pot to each circuit to be able to adjust the LED brightness.

Now the issue I'm having is that I'm still getting a "pop" when the foot switch is engaged. Especially on the fifth/last channel. My understanding was that the "click-less" switch was intended to avoid this very scenario. Has anyone else experienced this problem? Is there a proven remedy? I'm looking forward to the communities help on this one.





Thanks!
The Roctopus

[madbean]

I have one of those and I did find from time to time a pop would come in (this was testing on the breadboard, I have not put it in a pedal yet). But, cycling the power fixed it up proper. Does it go away if you unplug your dc jack and then plug it back in after a few seconds? Also, how are you powering it...does it daisy chain off anything else?

[Thomas_H]

I had a look at the module and despite them saying it beeing popp-less I dont see any component which mutes the signal.
There may be a resistor between effect out and GND but this does not really prevent popping.

The only way a Relay True Bypass "prevents" popping noise is that it switches faster than a mechanical switch.
It does not prevent the sudden discharge of in- or -output caps in your effect which is the cause of the popping.

I have collected a lot of information about switching which can be found here. http://diy.thcustom.com/knowledgebase/
Its worth reading.

[rullywowr]

I've reverse engineered this circuit and traced it out. It uses cascaded 2n7000 fets to pull down the output when switching. Trying to recreate it myself, I was never fully impressed with how it functions.  The popping could also be caused by the led. Try taking the led out of the circuit to see if that changes anything.

[Roctopus]

Hey Brian! I tried unplugging the DC jack like you suggested but it still pops. It's being powered by a Voodoo Lab Pedal Power 2 Plus. I've also be experiencing a ultra-brief, but noticeable, signal loss between when I engage a foot switch and when it actually comes on. Not sure if that explains or helps anything to know that but figured I would share.

I have one of those and I did find from time to time a pop would come in (this was testing on the breadboard, I have not put it in a pedal yet). But, cycling the power fixed it up proper. Does it go away if you unplug your dc jack and then plug it back in after a few seconds? Also, how are you powering it...does it daisy chain off anything else?

[mgwhit]

I've also be experiencing a ultra-brief, but noticeable, signal loss between when I engage a foot switch and when it actually comes on.

Both of the reviews on Mammoth's site mention this latency.  I don't think there's necessarily anything wrong with the ones you have -- I think it's just a dud product.

[pickdropper]

The ultra-brief signal loss is probably the mute function (I believe that switch has one).  I guess it isn't long enough to catch the pop.

[rullywowr]

The ultra-brief signal loss is probably the mute function (I believe that switch has one).  I guess it isn't long enough to catch the pop.

Agreed. I traced this circuit out and while the idea is solid, i never got it to work 100% on a breadboard or in PCB format. The 2n7000s mute the signal however there is still potential for popping. Id try to remove the led and see if that helps as the sudden rush of current can cause pops.

[Thomas_H]

Even using a mute-function can cause a switching noise. It will not be a loud pop but still a clicking or switching noise when you are switching while you have signal.

This is just because switching a live signal is only noiseless if the signal is switched while it crosses zero.

Does the switch cause noise when you have muted your input/ guitar ?

[Roctopus]

Ok I'll try removing the LED's and see if the popping persists and report back

The ultra-brief signal loss is probably the mute function (I believe that switch has one).  I guess it isn't long enough to catch the pop.

Agreed. I traced this circuit out and while the idea is solid, i never got it to work 100% on a breadboard or in PCB format. The 2n7000s mute the signal however there is still potential for popping. Id try to remove the led and see if that helps as the sudden rush of current can cause pops.

[Roctopus]

I can't remember off the top of my head but I'll give that a shot before I start removing the LED's and let y'all know.

Even using a mute-function can cause a switching noise. It will not be a loud pop but still a clicking or switching noise when you are switching while you have signal.

This is just because switching a live signal is only noiseless if the signal is switched while it crosses zero.

Does the switch cause noise when you have muted your input/ guitar ?

[Roctopus]

So I contacted with the guys at Mammoth and they were quick to respond with some helpful information. Like many have suspected there is indeed a "mute" function to the board. They sent me info on a way to remove this feature. Once I did what they suggest the latency I had been experiencing was complacently gone I am however still experiencing some slight "popping" especially when I engage the channels where my delay and reverb are patched. I imagine there's an issue with my ground connections or possibly my LED (w/mod). I'm going to check that again before removing the LED's or adding additional pull-down resistors.

[Roctopus]

Hi friends,

So I tried a few more things such as adding a 2M resistor across the tip and sleeve of every jack. I also removed the LED's from the circuit but I'm still getting noise. I was told that it could be a grounding issue so I have attached a wiring diagram since I couldn't get a detailed enough picture. Let me know if you all have any other ideas