Noise from relays

[eddieod]

Hi all,

I've recently modified a GArts Midi Patcher. It's a similar unit to the gcx switcher but this one used cmos switching using CD4053's so I didged all that, used the control switching of the cd4017's from the midi board in order to control relays for the actual signal switching in order to have a more transparent tone. This operates just fine but...I have a lot of noise in the signal path now! All relays go from a 9v stabilized power supply via a 1n4007 diode for each relay (in order to isolate each power supply node from relay to relay) to the relays itself. On the coils, I've installed another 1N4007 in parallel with a 10uf cap and from there the other pole of the coil goes to one of the switching outputs of the cd4017's. I think it has to do with the coils as with each loop (I've got 10 of them), the noise increases more and more...
Any suggestions will very much be appreciated!

Edwin
Maarssen
The Netherlands

[R.G.]

But at least you have a more transparent tone... 

[eddieod]

Well,.....yeah R.G....that's true.... :icon_cry:but the noise level is so high, it's unusable....
So...anyone any suggestions?

Edwin

[R.G.]

What *kind* of noise are you getting? Hiss? Hum? Switch pops? Radio pickup?

[eddieod]

To me, it kinda sounds like induction. It's a mixture of hum and hiss...

Edwin

[MarcoMike]

which relays are you using? and how stabilized is the supply?

I'm asking because I was scared I would have introduced noise when I used relays for the loop switching in my tube amp.... instead I was extremely surprised I got no noise at all, not even switching noise! (using OMRON relays and 7805 for the supply)