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jshep0102
Total Posts: 290
Joined 11-16-2012 status: Enthusiast |
I get hum when I plug a 2nd(brand new)mogani cable to play in stereo through my mixer. I don’t think it’s the usual suspect in ground loop. I have a Furman AR-117 for power. MOXF, mixer, and both speakers are plugged into it. I have other stereo channels I’ve moved to that don’t have issue with what’s normally plugged into them and it’s still there. I don’t hear hum in my cans, though. Any thoughts? Thanks, Shep |
Bad_Mister
Total Posts: 36620
Joined 07-30-2002 status: Moderator |
“Brand new” cables and expensive brand new cables are not immune to carrying ground hum… in fact, they carry it even better than old brand ‘X’ cables - which also carry it, but not with quite the same robust sound quality. You are hearing that ground hum as well as it can sound…
Ground issues are usually caused by the interconnection of electrical devices in a system.
You only mention the MOXF, the mixer and speakers… any thing else connected in your system?
Disconnect the computer and see if the ground issue disappears… Not that it is the cause, but it is the device that is different from the others. and may need some help sorting out AUDIO. You mention a second cable. We assume these are standard unbalanced signal cables (TS), Correct? |
jshep0102
Total Posts: 290
Joined 11-16-2012 status: Enthusiast |
Yes, sir, both are TS, both are new. I’ve also used some cheapies that I know still work (tester says they all work)and get the same result. The MOXF is the only thing connected to the mixer at current time. As soon as I unplug the right cable from the MOXF, hum is gone. I took everything else out of the mixer (and unplugged) to isolate the MOXF. The pc outs plugged in by themselves in the same channels alone don’t hum in stereo. Oddly, the MOXF stereo outs connected to 2 mono channels and panned hard left and right don’t hum!?! So I wonder why all my stereo channels hum with the MOXF plugged in?!? Yet my pc does not hum in them, despite it’s build… I put 4 mono rca to 1/4” adapters on the ends of a stereo rca home audio cable - no hum! I put my ebtech hum eliminator on the right 1/4” output cable, no hum! This is weird. |
Bad_Mister
Total Posts: 36620
Joined 07-30-2002 status: Moderator |
What mixer is this? and what are the channels rated for (what are they looking for as input level?) ? I don’t understand what this is for ? You used this to connect to the stereo channels of your mixer? |
miden
Total Posts: 618
Joined 09-22-2005 status: Guru |
Do you by chance happen to have the USB cable connected to the MOXF? |
jshep0102
Total Posts: 290
Joined 11-16-2012 status: Enthusiast |
USB has disconnected all along - thanks for the thought. I was trying all cables/options I have to see what could be causing hum. Oddly enough, a simple rca cable with 1/4” adators caused zero hum in stereo… My board is switchable -10/+4. Using -10, not that it changes anything other than the output level. Hums in stereo louder or quieter. Fortunately playing live I don’t use the mixer for anything but keyboards. So mono channels panned L/R it is. Rehearsals will just hafta hum, as I use 5 of the 6 mono channels for voice. Thanks very much to both of you for offering assistance. I appreciate it very much, Shep |
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
Strictly from a connection standpoint, the RCA with 1/4” adaptors should be the same as using TS cables. Is the RCA cabling a pair that are molded together over most of their length? Also, how long is the RCA type length versus the TS cables? |
jshep0102
Total Posts: 290
Joined 11-16-2012 status: Enthusiast |
Molded together, 15’ or so long. 20’ TS. TS work great in mono channels. |
DavePolich
Total Posts: 6820
Joined 07-27-2002 status: Guru |
You need to rule out your mixer as the problem. Borrow or rent another mixer and see
|
5pinDIN
Total Posts: 11891
Joined 09-16-2010 status: Legend |
It seems that you’re experiencing some common-mode 60Hz noise which is somewhat different on the two channels. It might be that with the RCA arrangement, the two cables running closely parallel to each other could be minimizing the problem. Do the audio cables run near power cords? If so, try to keep them separated as much as possible. What brand/model is the mixer? |