Filter experiment - noisy result. any suggestions?

[mlabbee]

Last night I took the Tremulus Lun eLFO and used it as the CV input to Tim Escobedo's Q&D VCF.  Basically, I'm trying to come up with a filter that sweeps in a rythmic pattern and eventually would like to build something with a couple of LFOs and a couple of filters with various options for combining them (and maybe adding an expression pedal) just to see what happens.  

So far, it seems to work fine, but I'm getting a TON of noise from the LFO - basically, you can hear the filter sweeping constantly.

Otherwise, the circuit has the desired result - a nice, smooth sweep.  I really like the LFO - it adjusts in some very nice ways for different effects.  So before I start breadboarding some more elegant filters, I'd like to see if I can kill the noise.  I have two theories:

1)  Breadboards are noisy.  Not sure I want to go through the hassle of perfing the LFO if this isn't it.

2) I'm getting a weird interaction from the two circuits because of how they are powered.  The LFO is powered as shown in the Tremulus Lune schem - 0 to 9V+ with Vr provided by a voltage divider.  The VCF is powered bi-polar - -9V to +9V with ground as Vr.  All power to both circuits is supplied by a Max1044 chip.  Could I be getting some kind of weird coupling effect?

Any thoughts or suggestions appreciated.

Also, any suggestiosn on nice filters for guitars? I'm thinking of trying the Mutron filter and the MS-20 filter.  I'd like to try more complex filters in the future (like some Moog filters), but am trying to keep it simple until I can get a handle on a good control system.

[puretube]

if it`s not a cyclic "clicking",
the noise is not from the LFO,
but from the audio path, IMHO.

(or stuff radiating into the audio...).

[mlabbee]

Part of it is definitely radiation - when I disconnect the LFO from the filter, but leave it running, the noise subsisides somewhat, but is still there. It's not a clicking - it's a lot of white noise that is getting processed by the filter.  I think I may just build an LFO circuit I found for a synthesizer and see how that works.  I'm also running into problems getting the TL LFO to really control the filter the eway I want it to, which suggests it may not be providing the kind of voltage variation I need to control the filter.

[puretube]

maybe you have an audio-level problem:

try to put in a boosted signal (couple of volts) and afterwards attenuate the filter output "back to normal" (i.e.: orig. guitar level)...

[Paul Perry (Frostwave)]

Is the 'white noise' present when the LFO isn't operating?
I have found that a low level of white noise that is not noticeable in a steady filter, becomes very noticeable indeed when the filter is swept.

What I mean to say, is that I doubt that just adding the LFO is going to generate noise of itself (apart from the clicking commonly found wiht unisolated LFOs).

If the noise is being swept even when the LFO is disconnected, it makes me think that there is severe coupling via the power rail. Does a few hundred (or preferably 1,000) microfarad across the power rail to ground make any difference?