Hum using K3 with Behringer Xenyx 808 Mixer

[Phillip Zminda]

I have been using a Behringer Xenyx 808 Mixer with my K3 in order to share headphone and powered speakers with other devices. When I connect the K3 audio output to any of the balanced inputs or CD input jacks on the mixer I get a very significant hum. I can overcome it with higher audio settings but it is particularly annoying with headphones and I really want to fix it. I have run a jumper from one of the chassis screws on the mixer to the K3 ground terminal, switched cables and inputs, changed AC sources on the mixer power supply and the K3 power supply and it still won’t go away. It doesn’t seem to be noticeable from other sources when I disconnect the K3. The mixer power cord is a 2 wire but can’t change that. Anyone using a mixer that can help me fix this problem? I would rather not have to disassemble the mixer if I can avoid it. Is there another device I could use for sharing audio that might work better?

Thanks,

Phil N3ZP
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[Jim Brown-10]

On 10/24/2014 8:49 AM, Phillip Zminda wrote:
> Is there another device I could use for sharing audio that might work better?

Yes. Look at the Rane product line. First rate American company based
near Seattle, they don't steal their designs from other companies. The
SM26 is 6x2. The SM82S is 8x3. Rane was the first company to eliminate
Pin One Problems from their entire product line, beginning in 1995. Pin
One Problems are the major cause of hum, buzz, and RFI.

http://www.rane.com/sm26s.html

http://www.rane.com/sm82s.html

Also, your hum problem may be related to how you are wiring your
interconnecting cables, how you are getting power for your station, and
whether you are bonding your station. Study
http://k9yc.com/GroundingAndAudio.pdf for detailed advice on power and
bonding.

For advice on wiring cables, study AN003 from

http://www.jensen-transformers.com/apps_wp.html

To feed a balanced input from an unbalanced output, do the bonding I've
shown, and use the "Minimal" Adapter Cable shown as Fig 2.1 in AN003. To
feed an unbalanced input from a tranformerless balanced output, use a
3-circuit plug (TRS or XLR) on the balanced output, but connect the tip
and the shell to the unbalanced input, with no connection to the ring.

73, Jim K9YC


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[Phillip Zminda]

Jim,

Thanks for all the info. I hoped that you might respond. I have read a lot of your articles. That’s a lot of homework. I suspected that it may possibly be a combination of connection issues. I may look into the transformer as a possibility or may just look for something simple with 2 unbalanced  inputs that will let me share the audio out my K3 with my FLEX-1500.

Thanks,

Phil N3ZP

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