buzzing hum - usb to mac

The Moog Forum Little Phatty & Slim Phatty Forum
1

Hi!

This is my first post, and I have a question.

I get a buzzing noise when I connect LPII via USB to my macintosh machine. It sounds like something grounding related, but Im not sure.
Any tips to get rid of it?

I dont like the sound of vacuum cleaners…
Please help me out! :unamused:

2

If it is a laptop try unplugging the power supply and run on the battery.

3

I had the same problem as you for the longest time. I can’t tell if its the Macbook or my Phatty that’s causing it, but connecting to it via USB will cause a hum to come out of the Phatty’s output.

The only advice I can offer is to switch to a standard MIDI/DIN plug:

instead of USB. I switched to a DIN plug and haven’t gotten any noise since.

EDIT: For what it’s worth, I did happen to notice that when my macbook was unplugged the noise would go away.

4

thank you! do you recommend any particular product or brand?

5

This is what I am currently using:
http://www.guitarcenter.com/Live-Wire-Dual-MIDI-Cable-100234419-i1166788.gc

Although, any one should work just fine.

6

I have this problem too.
I just got my Phatty upgraded to the full stage II specs @ the factory (+CV output mod).
When I connect it to my Mac Pro via USB, I get low hum+ hi pitched whine in my audio path.
The noise goes away if I revert to normal MIDI cables.

Has anyone noticed any MIDI performance difference between MIDI via USB and normal 5 pin DIN MIDI?
Particularly with regard to recording/playing back 14 bit automation?

Thanks.

7

I used an M-audio Uno for a couple years without issue.

8

there’s a “fix” for using USB also - requires only a small piece of tape or similar:

http://forum.moogmusic.com/viewtopic.php?f=11&t=15694&p=114307#p114167

9

Now I’ve seen it all : )

Seriously, I have Mesa Bass Amp that has a ground loop switch on the back; it does magical and wondrous things but I never opened it up to see what it’s actually doing? Perhaps just dropping ground from some part of the circuit?

But I had a Matrix 6r that, depending on where I plugged it in was absolutely horrible. So I wired in simple switch, problem solved. Was always concerned about lightning (literally) striking and frying something; we get pretty bad thunderstorms where I live and the power quality is not very good.

In this case though, great to see a fix for so many! That thread is a good read.

10

UPDATE
My Phatty was plugged into a Dlink USB hub.
When I plugged it directly into the Mac Pro on the front panel the problem seemed to go away, or at least be seriously reduced.