Analogue / digital signal chain conflict

[Schlippy]

Apologies if this isn't the right place to ask this.

 

I've got an analogue overdrive pedal with multiple outputs that I basically use as a splitter, only occasionally engaging the drives themselves. I've noticed a couple of my digital pedals really don't like being downstream of it, they start kicking out weird oscillating effects or feedback-y howling / rushing noises (thought the digital pedals were on the blink initially, but they're fine in isolation and the problems only occur when chained after the OD).

 

Is that a sign of something dying / going wrong inside the overdrive, or is just bad luck and some pedals don't play nicely together? I've been meaning to get a dedicated splitter anyway but could do without the extra expense at the minute (or a bench fee for opening up the overdrive if there's nowt wrong with it).

Edited January 25 by Schlippy

[warwickhunt]

Are you using independent power supplies or are they all running off one?  My TC Plethora does strange things if I power if from a brick that is supplying power to other pedals, regardless of the fact that the supply is strong enough.  I resorted to ensuring the Plethora (digital) had its own supply and no problems since.

 

Not saying it is that but worth looking at.

[Schlippy]

I isolated the power supply to both digital pedals when they were playing up as a first test (most of the rest of the chain were sharing a 5-way adapter, but the pedal under test had it's own 9v adapter going straight into the wall) and the problems persisted then.

[Suburban Man]

Is it possible that you're overloading the digital inputs? What happens if you turn down the volume on your bass slightly?

[Schlippy]

Just tried it with a chain of bass -> suspect analogue pedal -> digital pedal -> amp, and with the bass volume fully down the noise issue is still there. Also noticed that from cold (i.e. the power to the pedal chain just turned on) the signal initially "bleeds" up to full volume like this, so it sounds like there's definitely something funky going on with the analogue pedal. Unsure what to tell a repair shop tho, other than giving them all this info.

Edited January 28 by Schlippy

[Suburban Man]

I think that you'd have to give them both the analogue and digital pedals and demonstrate what was happening. Like the power supply suggestion, I can only think that some sort of digital interference is getting into the analogue pedal, which is then feeding back into the digital pedal ... etc. etc. 

I guess you could try separating them a bit, like 10-12 ft? Or checking the screening on the analogue pedal - its a difficult one when everything works on its own, but not together.