Trem ticking - from the battery?

[sfr]

So I absolutely *love* my TremFace (made from the layouts and info at Geofex) but there's a bit of a tick - well, not quite a tick, not quite a throb -  almost a "whoop" - pretty much the only time you hear it is when there's a lot a of gain going on and I'm not playing.  This is present even when the pedal is bypassed, however.  It's minor enough that it's basically a non-issue for me. 

I replaced the battery the other day (for the first time, despite constantly having the thing powered up - sucker lasts a long while!) and noticed that the noise goes away - or at least becomes much less noticable - the farther I have the battery from everything else.  Of course, I generally like to have my batteries *inside* the pedal itself, it seems to work better that way. 

At some point I'll get around to getting a positive ground power supply setup for my pedals that require it, but I'm not sure - would that help in this case?  Or would the noise then just eminate from the powersupply connection then?

What causes this?  I've never had noise come from the battery before.  It's interesting.  Is there a way around this? 

[col]

I have had a lot of trouble from noisy batteries and have never got to the bottom of it. Even if showing 9v some batteries impart noise into circuits for no apparent reason. Also, even if a battery is brand new don't assume that it is a good 'un. I spent ages trying to debug two circuits I built over the weekend only to find that the brand new battery was a dud! Imagine how I laughed....

Col

[Paul Perry (Frostwave)]

Maybe the sudden pulse of current to and from the battery as the LFO oscillator switches over is coupling to somewhere in the circuit. You could try using shielded wire for the battery lead (yeah, crazy idea... but why not try it? and let us know).
Also any internal resistance of the battery will make it worse, so try 470 microfarad across the battery(at the board, not at the battery itself). And one of those little ceramic bypass caps as well, for luck (.1uF)

[sfr]

Good thinking Paul - I'll try that out and get back to folks.

I wonder, looking at the schematic ( http://geofex.com/Article_Folders/trem_face/tremface4.htm ) there's that mystery capacitor ("CX") that I left out of my build - I wonder if playing with something there, if that would help fix things as well.

I also modded the input buffer for a little more gain so the thing would be unity (actually slightly louder to make up for the natural "quieting" effect of a trem) with the true bypass - I wonder if that effects things.

Regardless, thanks for the ideas.

Edit:  Those mods I spoke of to the input buffer are here: ( http://www.diystompboxes.com/smfforum/index.php?topic=46301.msg348359#msg348359 ) ( after some help from R.G. )   but now I'm looking - if the drain and source are conducting, won't I be getting DC current coming out the drain as well as my signal?  And I assume that's the purpose of the 1uF cap after the buffer, to block DC?  But if the DC is pulsing with the LFO, then it can get through?  So adding something in for Cx could help attentuate this?   I have a very tenous hold on what I'm speaking of here, I'm still learning this stuff!