high pitched noise with the white whale

  • i have a white whale module that is giving me gnarly high pitched noise when i plug in my grayscale 128. i have it plugged into the external +5v ac adapter, but it gives me the same noise even without it. as soon as i unplug the monome, the noise is gone. it's super weird because my ww module is plugged into my doepfer monster base and all of the mixers/sound sources are in a separate monster case. i don't hear the noise until i patch one of the trigger outputs to something in the top case.

    it's slowly driving me insane. is there a way to fix this? is anyone else having this same problem?

  • Do you have the ext5v adapter? Or just using your case 5V rail?

  • yup, i have the ext5v adapter. it doesn't make a difference though.

  • this sounds like a ground loop issue. basically the noise from the grid is getting into the case via the power supply. easiest solution is a ground-lift on either the ext5v or one of the cases, but i'm not familiar with the case so don't know if it needs chassis ground (most eurorack cases don't use chassis ground at all).

  • @galapagoose would plugging the ext5v power supply into a different outlet help in such situation?

  • I'll try both of these suggestions when I get home. Thanks!

  • I have the exact same problem with either WW or MP in my Enclave case with the Ext5V. The case uses a MakeNoise power bus board. Any suggestions on how to improve it? I tried with the Ext5V in a different outlet, but the noise is even worse. How would I add a ground lift to the adapter?

  • http://en.wikipedia.org/wiki/Ground_lift_plug

    this is used frequently in the audio world. they're less than $1 at a hardware store. get a handful.

  • on my way to home depot.

  • Let me know if it helps. I'm also going to try a couple of different PSUs. I've got one of the Synthrotek ones on hand and am going to try borrowing something else as well...

  • if you have a PSU with no ground (two prong only) it'll work. you can lift either the modular or ext5v.

    it absolutely works! i lift my ext5v.

  • My PSU does have a ground, it's a 3 prong plug just like the brick that came with ext5v

  • Okay, I did some further testing today. I got an Intellijel power supply and connected the White Whale to that, then connected the outputs from the WW in to my Enclave case with MakeNoise Power Bus board. There was absolutely no noise even with the mixer cranked to full.

    I tried using the Ext5v in the same configuration, WW on Intellijel power supply, rest of system in the Enclave, and there was again a ton of high pitch whine.

  • $.69 ground lift plug fixed it! thanks!

  • I have some beefed up voltage regulators on order to provide 1.5A of +5V on the MakeNoise boards as well, I'll see what it sounds like running directly off that once I get them in a few days.

  • @seank: ground lift on your PSU or ext5v?

  • ground lift on the ext5v adapter.

  • even if you power directly from the case (with a high powered 5V), you'll encounter subtle issues (typically) due to the shared ground path between your entire system-- this can mean wobbling ADCs/DACs when the amount of lights on the grid change dramatically.

    best practice: use an ext5v, ground lifted (if your modular has a ground prong)

  • Ok, I'll try getting one of those and see if it helps with the adapter.

  • Well, apparently ground lift plugs / cheaters aren't sold here because they're unsafe. Guess the regulations must be looser down in the US :)

  • Lately we have been finding out that a lot of regulations and laws are pretty loose here in US...

  • get a hack saw and cut off the ground prong. IEC cables are $1 as well.

  • Dremel made short work of that pesky pin. All is good now :)