EH Pulsar

[crang85]

ive built an EH Pulsar from tonepad and whenever ive got it connected without playing it there is a clicking sound coming from my amp. any ideas.

[StephenGiles]

This is an awfull pedal - don't waste any time on it.
Stephen

[strungout]

It's certainly not the best trem I heard, but I like it The clicking sound is always there, you just can't hear it when you're playing. Basically, it's the oscillator that'S causing this. I don't remember seeing any fix for it , but if you search the forum, you might be luckier.

Ciao.

[travissk]

I'm not familiar with the layout and what type of LFO it uses, but I've heard of that pesky ticking before.

puretube mentioned a little bit about it at the end of this thread.
http://diystompboxes.com/sboxforum/viewtopic.php?t=18058&highlight=pulsar

[jimbob]

I just perfed it. Havnt tried it yet, but if there is a tick youd think someone has figured out a fix by now..esp around here..at least id like to think so. Far too many smart people not to have. :lol:

[puretube]

IIRC, I saw that the tonepadsite just took the "pulsar" or
"pulsar-WORKALIKE" (like it should be named),
down due to tickyness.

to be clear: that was a clone of the ancient E-H pulsar,
not to be confused with the new one, aka re-issue...

[Zero the hero]

I don't know how you wire the bypass section, but there are different ways to bypass an effect.
I had the same problem with Pulsar recently, and I solved it by wiring the circuit, for example, as shown in this Big Muff pic:
http://www.generalguitargadgets.com/diagrams/bmplo.gif
Input of the pulsar should be connected to ground when the effect is bypassed.

[Mark Hammer]

I'm not the expert in such matters, but LFO tickyness is generally a product of sudden surges in current demand as the basic square wave of the LFO (which is then *transformed* into a triangle or similar waveform) swings high and low.

Thesolution is to decouple the power supply to the audio portion from the power supply to the LFO portion, by smoothing the supply lines to each of these respective halves.

In the Tonepad layout, C2 smoothes the supply out for the entire circuit, and C5 is intended to decouple the bias voltage fed to the input of the op-amp from the rest of the supply.

There seem to be a few things one can do to improve matters.  First, increase C2 for more "current reserve" (e.g., 100uf or even 220uf).  Second, increase C5 to 33 or 47uf and maybe even increase R5 a bit.  Bear in mind that the original used a garden variety op-amp and feeding less current in the bias voiltage may be appropriate for use with a BiFet device like a TL072.

Third, the supply to the LFO shares the same V+ line as the op-amp itself.  It may be appropriate to stick a small resistor/cap combo between V+ and where it connects to R17-20 to further decouple it.

Finally, there is producing a current-related tick and hearing one.  Stick a .001uf cap in parallel with R4 and the tick will be slightly less audible.