Ground Hum

JavEspi 4:57 AM - 9 May, 2012

No problems until I plug in the mini display port to VGA adaptor into my Mac. Major ground hum. I've been able to reduce it using the Attenuation switch located next to the XLR outs on the unit. But its still there, enough to show signal on the LED light on the back of my powered speakers, QSC KW152 and KW181 Sub...and I can hear it! Now the crux.... When I use my SL1 box with my Denon mixer, Pioneer CDJ350's, same laptop, same setup, same venue, NO NOISE at all!
This is very frustrating because I depend on spinning video in my venue and cannot have a hum creeping in on low volume spots in my set.
If you suggest a GLI, please explain where I need to place it. I've read other posts and I have replaced power supplies to my mac and power strips and reconfigured how my wires are running in proximity of each other. I do not want this piece of equipment to sit in my garage and collect dust. Any ideas?

lofty 4:28 PM - 9 May, 2012

Try to unground your projector

What I do (although technically not recommended)

Grab an old extension cord an rip out the ground.
Then plug your projector to the ungrounded cord.

Proper solution --- buy a ground loop box from any music store/guitar center.

Martin C 4:19 AM - 18 May, 2012

Hi JavEspi,

Do you have a power supply connected to the DDJ-S1?

Have tried using the RCA outputs on the DDJ-S1 to see if that makes any difference?

phatbob 9:27 AM - 20 May, 2012

I'm having the exact same problem with my Twitch.

It only seems to happen in one venue though, which makes it even stranger.

I've got a ground loop isolator between the outputs of the Twitch and the inputs of the house mixer.

What seems to have made a difference, no idea why, but I ran a phono cable from the Aux input on the Twitch to another line input on the mixer. Obviously it means I can't use the Aux in, but it seems to have created some kind of loop and cuts the noise right down.

You might want to try that.

JavEspi 5:38 PM - 20 May, 2012

Thanks for the input. After considering all three ideas, I found an ART DTI Dual Transformer/Isolator. Its XLR in/out. I was told by a close friend he used a Furman Isolator which I couldnt find anywhere. Ill try this next time I work and update this discussion.
Thanks!

phatbob 6:00 PM - 20 May, 2012

I'd be very grateful to hear how that ART box works out for you. I've just looked at it online and the reviews seem positive, but as you and I have exactly the same problem, I'd love to hear your results!

Thanks

JavEspi 8:18 PM - 20 May, 2012

Expect to hear about it Tues night around 11:00pm!!!

phatbob 8:19 PM - 20 May, 2012

Lol... good luck!

Martin C 2:06 AM - 21 May, 2012

Definitely keep us updated JavEspi :)

JavEspi 2:35 AM - 23 May, 2012

10:35pm......
Verdict on the ART DTI Dual/Transformer Isolator.....
SUCCESS!!!
No ground noise @ 0 db Master Attenuation.
Coming out XLR from the DDJ-S1 into the ART DTI and thru out XLR to my Drive Rack PX.

To quote Gene Wilder in "Young Frankenstein",
"IT...CAN....BE...DONE!!!"

Thanks for all your suggestions.

phatbob.... I recommend this product.

phatbob 7:05 AM - 23 May, 2012

Thanks for letting us know, JavEspi. I shall be ordering one today!

Martin C 7:13 AM - 23 May, 2012

Oh awesome, definitely appreciate the tip-off JavEspi, I know a few people that could benefit from something like this :)

JavEspi 1:19 PM - 23 May, 2012

good luck and thanks.

Martin C 7:12 AM - 24 May, 2012

I will close this thread now, but feel free to re-open at any point if you do need further assistance :)

Software help archive

Ground Hum

Search Results