Tremolo Issues - clicking noise

[alfonso_bundis]

Hi everyone,

I recently assembled a Tremolo for a friend using a Musikding "Der Puls" kit.
Overall it works fine, specially when I test it with my practice amp. But with
my friend's 500 W Marshal amp we can hear come clicking noise. Is there
something I can do to avoid that?
Here is the schematic:
http://diy.musikding.de/wp-content/uploads/2015/03/pulsarschalt_errata.pdf
Thanks in advance for any advice you can give me.

Cheers

[Kipper4]

The lfo looks like it has a seperate power supply bias. so lfo ticking should be minimum.
did you make the red connection. i'm guessing you did or it wouldnt work,
hmmmm

[alfonso_bundis]

The lfo looks like it has a seperate power supply bias. so lfo ticking should be minimum.
did you make the red connection. i'm guessing you did or it wouldnt work,
hmmmm

Yeap, I did that connection. testing with my headphone rig I can only hear the clicking if I push the volume close to max

[Kipper4]

and if you turn down depth at max volume?

[anotherjim]

Something wrong with that schematic. T3 collector? Where is go? Rate pot P2a?
Does Switch 2 position make a difference? Keep the wires to that as short as possible.
I can't see that the LFO design here could pulse much current which is a common cause of clicking.

[Kipper4]

I think it's based on this jim

http://www.tonepad.com/getFile.asp?id=29


Seems a common complaint

http://youtu.be/SIJfn0sbTrw

As Paul demonstrates

[Elijah-Baley]

The lfo looks like it has a seperate power supply bias. so lfo ticking should be minimum.
did you make the red connection. i'm guessing you did or it wouldnt work,
hmmmm

Try to take a look here: http://tagboardeffects.blogspot.it/2013/07/ehx-pulsar.html.
A couple of components could be solve the problem.

Good luck!

[anotherjim]

Ok, well I was right about that wire in the Musikding scheme.
My best bet might still be radiation from the switch wires to the audio path, especially if as Kipper4 suggests, it ticks with the depth minimum.
I'd also be tempted to use screened wire for the signal input to the board and keep those switch wires well away from audio.

I've never had one of these, but it might tend to be ticky when the smaller .022uF cap is switched in compared to the larger .22uF one.

In could be LFO action getting to the op-amp power supply, as mentioned in that tagboard discussion that Elijah links - but rather than filtering the LFO supply, isolate the op-amp with it's own filter -  that is 220R from 9v to pin 8 and 47uF cap from pin 8 to ground.

[duck_arse]

that opamp is being abused with its input tied to ground. is there any chance that tikking could be a flow-on effect? there was a previous thread with pulsar/das puls tikking .....

[alfonso_bundis]

Thank you all for your replies

and if you turn down depth at max volume?

Just tried this, the clicking remains regardless of how I turn the depth pot.

The lfo looks like it has a seperate power supply bias. so lfo ticking should be minimum.
did you make the red connection. i'm guessing you did or it wouldnt work,
hmmmm

Try to take a look here: http://tagboardeffects.blogspot.it/2013/07/ehx-pulsar.html.
A couple of components could be solve the problem.

Good luck!

Ok, well I was right about that wire in the Musikding scheme.
My best bet might still be radiation from the switch wires to the audio path, especially if as Kipper4 suggests, it ticks with the depth minimum.
I'd also be tempted to use screened wire for the signal input to the board and keep those switch wires well away from audio.

I've never had one of these, but it might tend to be ticky when the smaller .022uF cap is switched in compared to the larger .22uF one.

In could be LFO action getting to the op-amp power supply, as mentioned in that tagboard discussion that Elijah links - but rather than filtering the LFO supply, isolate the op-amp with it's own filter -  that is 220R from 9v to pin 8 and 47uF cap from pin 8 to ground.

Thanks for the tips, will try to add the cap and resistor to pin 8

[alfonso_bundis]

Hey guys, just as an update. Adding the cap and resistor worked. Now I barely notice any noise. Thanks for all your help.