Multi Build Noise Issue (fixed -kind of)

[AllenM]

Hey guys.. I put together a multi build http://www.madbeanpedals.com/forum/index.php?topic=27708.0 and I am getting a "whine" from the Boost section. After some testing I have verified that the boost circuit when removed from the multi build works normal. Upon further testing I noticed the whine would change pitch when touching the TC1044S on the boost and the Klon, so it appears I am getting some type of interference with them both in the same enclosure. Hoping there is a solution to possibly isolate the circuits from each other, otherwise it looks like I will need to replace the boost with a different circuit.

Here is the link to the tech support on the noise issue under the JMK section with a video link.

http://www.madbeanpedals.com/forum/index.php?topic=27698.0

Any help or suggestions appreciated.

AllenM

[gordo]

It'll jack up you beautiful wiring but can you remove one of the charge pumps and power one of the pedals with the other's pump?

[EBK]

A few ideas:

Have you tried powering each board separately to see if the whine is present?

Do you have a spare charge pump chip you could swap in? 

From the pics, it looks like you have separate ground wires for everything, right (star grounding)?  Or, does something share a ground wire with something else?  I'd recommend each board with a charge pump have its own ground wire directly to the DC jack.

Also related to grounding, it looks like you've bundled some ground wires tightly in parallel.  A long parralel path makes it easier to transfer noise from one wire to another.

[EBK]

Yes, check your total current requirements, and if feasible, consider doing what gordo suggested.

[AllenM]

To gordo - I was wondering if I could run the boost from the Klon charge pump - I will have to look at that option.

I also thought about adding separate power jacks for the two devices but then that defeats the purpose of the all in one, plus most people I know use a daisy chains power cord  so it should end up the same.

The Klon plays fine with no whine at all - I only hear the whine when the Boost is active, otherwise the pedal is dead quite.

I did star ground and everything is separate. I replaced the chips in both units just to be sure and the whine remains.

In the long run I may just change out the Boost to another circuit that does not have a charge pump.

I have not considered the ground to the DC jack - currently it is tied to the Input jack with the rest of the ground connections.

Thanks for all the input and suggestions.

AllenM

[AllenM]

Well the pedal needs to be on stage tonight so I replaced the booster with a JMK Beauty Booster and all is well. I may revisit this issue in the future if I decide to combine two circuits using charge pumps.

Again thanks for the recommendations and input.

AllenM

[gordo]

I've had a few similar issues with separate stand-alone effects and that was my approach too, replace.  Still, it would be nice to figure out what's causing the noise (is it called heterodyneing?).  I'd try driving the Wak with the Klon to see if it helps.  If it's two separate enclosures I have no idea how you'd decouple them.

[Scruffie]

Two things come to mind, did the TC1044 come from Tayda? I've had problems with the clock frequency in them being audible before and the other is that the two chips are heterodyning, check for any ground loops in your wiring, try some additional power filtering between the two boards (haven't looked at the schematics for the projects so I don't know how much there is currently) try shielded wiring for power and grounds for the two boards.