Ringing noise when running audio through slim phatty

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cfernn
Posts: 2
Joined: Sat Jul 09, 2016 3:27 pm

Ringing noise when running audio through slim phatty

Post by cfernn » Sat Jul 09, 2016 4:11 pm

I'm running audio from an output on my RME Fireface to the audio input of the slim phatty. When I open the filter I hear a constant ringing sound, like electrical interference of some kind, maybe from the computer.

I have an assortment of pedals and effects units sitting right next to the slim phatty and when I run audio through those (from the same output/cable) I get zero ringing.

Anyone know what could be causing this?

Note: I'm activating the filter using the filter cv as well as plugging a cable into the kb gate

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_DemonDan_
Posts: 1273
Joined: Mon Nov 16, 2009 4:52 pm

Re: Ringing noise when running audio through slim phatty

Post by _DemonDan_ » Mon Jul 11, 2016 10:14 am

cfernn wrote:I'm running audio from an output on my RME Fireface to the audio input of the Slim Phatty. When I open the filter I hear a constant ringing sound, like electrical interference of some kind, maybe from the computer.
Hi cfernn,

Computers spew a lot of interference, as you suggested. It gets worse when the audio chain is not gain staged optimally.

If you can get a hotter audio signal to come from the RME, you'll be able to reduce the OUTPUT VOLUME knob on the Slim Phatty. The more you can do this the less you'll hear interference. At some point, though, it will start distorting (as it's designed to do).

You can also try to keep cable runs as short as possible, and keep data and power cables away from audio cables. (And never leave any of those cables coiled.)

Getting the Slim Phatty farther away from the computer might also help. Is the Slim Phatty connected to the computer via USB?
_ :twisted: _DemonDan_ :twisted: _

cfernn
Posts: 2
Joined: Sat Jul 09, 2016 3:27 pm

Re: Ringing noise when running audio through slim phatty

Post by cfernn » Mon Jul 11, 2016 12:55 pm

Thanks for the informative reply.

I did some more tests later last night and found that the ringing is definitely coming from the computer but is barely audible through other pedals, even through a moog mfdrive pedal with the input and output cranked. It's like the phatty is just picking up more noise. I'll try what you suggest. It's not plugged in to the computer but it's sharing the same outlet.

Stevie Ray
Posts: 254
Joined: Sun Apr 17, 2016 2:25 pm

Re: Ringing noise when running audio through slim phatty

Post by Stevie Ray » Mon Jul 11, 2016 6:24 pm

Separate the AC mains inputs, as far as possible, from the computer and the other instrumentation in your rig. Use different AC wall sockets as far apart as possible between your computer and your mixer/instruments.

Make sure the cables that connect your instrument to your audio interface/PC have a solid ground connection.

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