Ticking/clock noise from Small Clone build when in bypass mode.

[Nocaster Cat]

Using the Tonepad schematic I created a Small Clone layout which works great except that I get clock noise/ticking when the pedal is bypassed (I did use true bypass switching) if I run a dirt/pedal after the chorus. So...

guitar > dirt/booster > chorus > amp = no issues

guitar > chorus > dirt/booster > amp = clock noise/ticking

I've checked the layout multiple times and as far as I can tell everything is fine. I seem to remember Analogman stating that the factory schematic contains errors but did not elaborate on what the errors were. Any thoughts, ideas or fingers pointed in the right direction would be greatly appreciated.

Thanks in advance.

[Mark Hammer]

1) Make sure you use a lowpower dual op-amp for the LFO.  Best candidates would be a TL022, LM358, or TL062.  The ticking is an artifact of the LFO suddenly sucking current to produce the square that it turns into a triangle.  Less current draw = less disruption of the rest of the audio path.

2) If that isn't enough, "decouple" the LFO from the rest of the circuit by inserting a 100ohm resistor between V+ and pin 8 of the LFO chip, and run a 10uf cap between pin 8 and ground (+ goes to pin .  This turns the 10uf cap into a sort of "micro-battery" to store and provide reserve current for producing that initial square wave, without impacting on the current available for the rest of the circuit.

These two actions will generally cure 90% or more of objectionable LFO ticking.  Of course, what is perpleing is why you hear this in bypass mode.  Is this true bypass, or is it set up such that "bypass" simply cancels the delay signal and your guitar still passes through part of the circuit?

[jimilee]

I used a TLO2272 that worked out great, but the lm358 is the recommended. Stomptown said that I may hear ticking other wise. The lm358 had the best sound coincidentally, I just finished  mine today.


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[Nocaster Cat]

1) Make sure you use a lowpower dual op-amp for the LFO.

I'm using a LM358.

2) If that isn't enough, "decouple" the LFO from the rest of the circuit by inserting a 100ohm resistor between V+ and pin 8 of the LFO chip, and run a 10uf cap between pin 8 and ground (+ goes to pin .  This turns the 10uf cap into a sort of "micro-battery" to store and provide reserve current for producing that initial square wave, without impacting on the current available for the rest of the circuit.

I will give this a try.

Is this true bypass, or is it set up such that "bypass" simply cancels the delay signal and your guitar still passes through part of the circuit?

True bypass with grounded input.

Thanks, I'll report back.

[Mark Hammer]

I used a TLO2272 that worked out great, but the lm358 is the recommended. Stomptown said that I may hear ticking other wise. The lm358 had the best sound coincidentally,

This is confusing.  The audio signal does not pass through the LFO.  Or did you mean "least audible ticking" when you said "best sound"?

[Nocaster Cat]

I haven't gotten the chance to mess with the circuit yet but do have another question. Why am I getting the ticking/clock noise when the pedal is wired for true bypass? Shouldn't the circuit be completely removed from then signal path with the effect is bypassed?

Thanks.

[EBK]

I haven't gotten the chance to mess with the circuit yet but do have another question. Why am I getting the ticking/clock noise when the pedal is wired for true bypass? Shouldn't the circuit be completely removed from then signal path with the effect is bypassed?

Thanks.

Try pushing your wires around that connect to your jacks.  Perhaps one is running too close or parallel to a clock line and picking up noise. 

[anotherjim]

It can pickup noise at the stompswitch.
Have you added a speed indicator LED and switched it with the bypass 3PDT?

[EBK]

Also, did you make your own layout?  In your original post, you mentioned referring to Tonepad's schematic rather than their PCB.

Got a picture of your work?