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Ground noise with Mackie DL1608?

Zephrant

Zephrant

Guest
Dec 10, 2013
313
94
Spokane, WA
#1
I bought the mixer in July, and it has had the same problem the whole time- When ever I connect it to an amplifier or powered speaker, I get a distinct hum at 2Khz, 3Khz and 6khz, and a raised noise floor. Turn off the mixer, or disconnect the XLR cable, and it goes away.

It does this at my place, at the drummer's house, and when fed in to four different amplifiers/powered speakers. I've used TS and XLR cables and disconnected everything else, but still get the noise. My Yamaha mixer does not have this problem with the same cables and amplifers.

It appears to be ground noise, as it doesn't vary with volume output from the mixer (it can be muted), but does vary with amplifier volume levels.

I've talked to Mackie (very slow customer service!), and they even sent me a replacement unit, which does the same thing.

The only solution is to use a ground isolating AC plug on the mixer, then all problems go away. It then works fine with all amplifiers. I repeated that test at the drummer's house (in another state even), so it's not something local to my house.

Mackie has given up, but I'm still thinking it's an design issue with the way they ground their system.

Anyone else seen this with that mixer? They swear I'm the only person in the world with this issue.

Attached are two screen shots- The mixer is plugged in to the wall and has one XLR cable attached to the amp, no other connections and no ipad on the mixer. The amp has one speaker plugged in to it. One picture is with the mixer on, the other with it off. No other changes.

As a side note, their tech support is nearly unusable. Can't be bothered to reply to some emails, slow to reply, asks for data I've already sent or to do tests I just told them I did, and in general were incompetent. They wanted me to ship my brand new mixer to their repair depot for diagnoses, but when I called they agreed to ship me a replacement. I'm very disappointed, and am having serious second thoughts about the SRM650 and SRM1850 speakers I wanted to get.
 

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#2
I can't comment on the mixer, but I can attest to the customer service and how they make it sound like you're the only person to ever have issues. My band has 3 of their powered subs and two have given up the ghost. They made it sound like they have never had issues with them and then I started reading the reviews. There are sixteen 1 star reviews on amazon out of 22 for our sub. I also talked to the repair place in Dallas we will send them to and the guy there said they have had quite a few of these come through, enough so that they probably have parts in stock to fix them. That said, we won't be buying any more Mackie stuff and we'll definitely be spreading the word around Austin to avoid them. Sorry that didn't help your mixer situation!
 
#3
this is the first i have heard of this issue to be honest. both as an owner and a dealer for mackie. out of curiosity is everything on the same power circuit? ie speakers/mixer etc?

assumably you have just plugged in the mixer only and speakers? and at what stage does the hum become introduced? as soon as you connect the mains, or connect mains and turn on speaker, or just power on the mixer without speaker connection?
 
#4
I have tried both ways- Even with the mixer and amp on the same power strip. Interestingly, if I ground-isolate the power strip only I still get the noise, which means it is the Mackie generating the noise that feeds in to the amp.

I want to try powering the Mackie from a bench power supply, to see if it is the in-line DC supply for the Mackie that is generating the noise.
 
#6
Isolate the problem:

Use the powered speaker with another mixer---- hum or no hum?

Use the mixer (same output) into another power amp/speaker configuration --- your bass amp will work for this------ hum or no hum?

Sounds like a ground loop to me----- TEMPRORARILY use a 3 to 2 prong adapter on the speaker power cord. If the hum goes away---- ground loop issue. If it does not, there is probably an open connection on the shield somewhere in the path. Try every possibility to be sure there is only one ground on the system (maybe the hot and neutral are reversed somewhere, but not likely)------ then consider having Mackie look at the equipment.
 
#7
Thanks John- I didn't put the details of hours of testing in the post, but I have tried all that. I can make it go away with a 3-2 prong adapter (ground lift the AC). All four amps/powered speakers work fine with other mixers. The mixer has the hum with all four amps, including one powered speaker in another city, in another state where ONLY the mixer was the same. With and without the ipad on the Mackie.

Mackie did replace the unit with one that was one hardware rev newer, still have the issue. Tried with the new power supply that came with the replacement mixer too.

I haven't tried a hum eliminator- I'll have to pick one up. If it works, I'd need it on all outputs though. I also get the hum though the aux outputs, using a TS cable to the mixer. So ground-isolating adapters appear to be required.

I've done a lot of electronic testing, and I'm stumped, as is Mackie. I was hoping someone else had run across this and knew what was going on.

Thanks for the help!
 
#8
My old PA consisted of various mixers, 2 JBL powered eons for fronts, 2 JBL powered eons for 2 separate monitor mixes. Sometimes I had 60 cycle hum, sometimes I did not. I carried several ground lifters (3 to 2 prong adapters) to gigs and often had to use them on all of the AC to the speakers--- always left the 3rd prong on at the rack.

It's a bit risky safety wise---- if you want to be 100% safe, clip the shield at ONE END of the cord(s) going from your mixer outputs to the powered speaker. That is a safe and cheap way to lift the ground.

john
 
#10
Big_Daws said:
john its never really safe to clip a ground...if something were to happen then someone will be screwed. its a temporary fix only IMO!...

i wonder if the mixer is having issues with your amps....
Click to expand...

Don't clip the EQUIPMET (chassis) ground--- the green wire on the power cord. Clip the shield (of the audio connection ie XLR)--- one end only. Perfectly safe--- open a direct box and see what the "ground lift" does.

jm
 
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#11
Hey I'm having the same problem with my Mackie dl1608. I was wondering if you found a solution? Sweet Water didn't give me any help and mackie kept telling me to use balanced TRS cables (I was) but the Balanced XLRs were giving me problems too. Any help would be great.
 
#13
walterw said:
are you making sure all these amps, powered speakers and the mixer are all powered on the same circuit?
Click to expand...
Not "necessary" if there's a common ground across circuits - which is supposed to be the case in the US per NEC specs. But we all KNOW that happens, right?
I use the poor-mans "star" ground approach in bars/clubs where amp rack is fed from 2 different circuits (get common ground via rack connections) and the backline distro comes off one of the same 2 circuits. Common ground.. no hum, no buzz. Tri-amp PA.
 
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#14
Nope, never solved the problem other than ground-lift the AC input to the mixer.

Note that the power brick has a two wire connection to the mixer. 12v and DC ground. I've considered replacing the 12v brick with a car batt, but can't be bothered yet.
 
#15
s0c9 said:
Not "necessary" if there's a common ground across circuits - which is supposed to be the case in the US per NEC specs. But we all KNOW that happens, right?
I use the poor-mans "star" ground approach in bars/clubs where amp rack is fed from 2 different circuits (get common ground via rack connections) and the backline distro comes off one of the same 2 circuits. Common ground.. no hum, no buzz. Tri-amp PA.
Click to expand...
Do you really need two circuits ? 1 dedicated 20 amp circuit will normally do me fine. I also do stereo triamped... And I can get mighty loud... Over time, I have found that multiple circuits can lead to grounding / phasing issues. Yep, there is code but electrical systems seem subject to Darwin... Biggest thing I run into is lines I am unwittingly sharing with refrigeration/HVAC, etc... So of at all possible, I pull frm 1 circuit for all the mains and a separate one for backline... And yeah, I get it's not always possible.

So far, my 806 has been quiet as a church mouse. I have had other oddities but noise hasn't been an issue for me...
 
#16
4Mal said:
Do you really need two circuits ? 1 dedicated 20 amp circuit will normally do me fine. I also do stereo triamped... And I can get mighty loud... Over time, I have found that multiple circuits can lead to grounding / phasing issues. Yep, there is code but electrical systems seem subject to Darwin... Biggest thing I run into is lines I am unwittingly sharing with refrigeration/HVAC, etc... So of at all possible, I pull frm 1 circuit for all the mains and a separate one for backline... And yeah, I get it's not always possible.
Click to expand...
No you probably don't, from a "power" perspective. But... it's going to be borderline/fail if a 4/5/6 piece band all run off the same circuit as the FOH/monitor amps!!

The TWO circuits to the amp rack ensures that I get adequate power AND the common ground across the system. In my area, there are many places with clean power.. not on icemaker/refrigerator circuits and stage power was planned during construction and not an afterthought.

Note that the same principle applies to powered speakers... the star/common ground, I have a breakout box (15 amp) that has 8 plugs on it.. with TWO power cables in, sharing a common ground that I will use if there are ground loops/hum from backline. One in each circuit. common ground. All backline splits tap into it.
 
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#17
I have the same issue with my DL1608 and DL806. When I plug my Roland TD-30 direct outs into any input on either the 1608 or 806, I get a loud whine/static noise. It's very loud. I've found if I disconnect the iPad from mixer, it mostly goes away. if I plug the TD-30 direct outs into some Hosa Sidekick DI's (DIB-443) and then go balanced out of DI's to DL1608 or 806, that removes the noise. If I lift the ground on the mixer like you've done, it also goes away. I've been using the DI method vs lifting the ground. It's been much better. Just seems to be some grounding issues between some device's outputs and the DL mixers.
 
#18
I have Mackie Dl1608 with a noise problem too. Its NOT a hum but a hi pitched whine. It is coming from the mixer. Not loud enough to be detected by anyone in the audience during a show but anoying to the musicians during sound check. Have ground lifted every thing but the mixer. It sounds to me like the high pitched whine of a digital switching power supply or some thing. Has anybody had this kind of problem before??
 
#19
Have a DL1608 which presented a hum problem once the Sound Loop for hearing impaired was installed. As others have experienced, the most effective way to eliminate the hum was to use a 3 to 2 prong AC adapter on the power brick for the DL1608. Lifting the ground on one side of the XLR on the output worked for a short time, but became ineffective when something changed (more mics were added and/or some other unknown change was made) and the XLR ground lift no longer worked.
 
#20
hey, a necro-bump!

one detail not mentioned in this thread, you apparently must use all balanced cables from the 1608 outputs, so XLR from the left/right and TRS from the monitor auxes.
 
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