How to eliminate LFO bleed?

zonkout · Joined: Oct 12, 2006 Posts: 33 Location: ozztin, teggsitz

I'd like to thank you all again for your help with this.

I haven't eliminated the LFO bleed, BUT it is far more subtle now--barely audible once I have a few different patches running simultaneously. Before I couldn't run a percussive patch and play along on the keyboard because the percussion would modulate the oscillators in the keyboard patch. Now I can patch up a little drum beat and play along without the intrusion.

The solution turned out to be very simple: a shorter cable of higher gauge connecting the psu to the case. I also put the noisy modules closer to the power supply in the chain. The connecting cable seemed to be the real issue, though.

The next step will be hooking up my distro boards in parallel to completely eliminate the bleed.

Thanks to you guys I can now fully enjoy my modular!

zipzap · Posted: Wed Mar 28, 2007 7:11 am Post subject:

just a thought, this may be complete nonsense:
isn´t it possible to run a critical module "inbetween" opamp buffers or gyrators?
i have used one transistor gyrators for critical amp circuits. on the neg and pos rails. mainly to get rid of hum and oszillation on the power rails (which seems to happen when you power a circuit with very little power needs from a 7812) is there no such thing for ground? like a opamp that buffers a 0v voltage as the ground of the module?
or would that make connecting to other modules impossible without a real ground connection?

Uncle Krunkus · Posted: Wed Mar 28, 2007 3:14 pm Post subject:

Sounds like a great idea. But I don't know if it's possible or not. Because the external connections are all referenced to ground, maybe there will always be contamination problems. Confused