Connecting Delta 1010LT to Powered Monitors?

R

rsilverst

New member
Hi-

I just purchased an M-Audio Delta 1010LT. Using KRK RP-5 powered monitors. Connecting via RCA unbalanced cables. Using PC, Athlon-based.

Here's the deal. I was able to configure the stereo monitor mix in the M-Audio control panel, no problem. Set the output level to either consumer or -10dBV. And I get good quality sound out of the monitors - BUT, if I increase the volume control *on the monitors* above the minimum (-30dB), then I hear a hum in the monitors. If I keep it at the minimum and get my volume through the sound card settings, it's okay. But I'm guessing that this is not correct.

Any ideas as to why I am getting this hum? Could it be noise being picked up by poorly shielded cables? I kind of doubt that, but I'm trying to figure it out.

Thanks!
 
does it still hum if you unplug it from the soundcard? try that and if it still hums then change cables. Also, make sure none of your signal cables are running parallel to your power cables. They should alway cross at 90 degree angles.
 
no hum when unplugged from card. different cable also causes hum.

i should note, and this is probably the issue, that i just ordered good cables, and since they hadn't arrived yet and i wanted to try these monitors out, i am using the RCA cable from a CD or cassette deck. these things are probably unshielded, right? and that would be my problem right?

and i'm an idiot, right?

:)

thanks.
 
well, if it were the cables, the hum would probably be there even when unplugged. Did you try setting the output to Consumer?
 
would the hum be there with it disconnected if it were the cables? i'm not sure... i guess if the cables are an antenna, then it should, huh...

when i set it to consumer, i still hear the hum. when i mess around with the cables and power cords, etcetera, the hum can be increased or decreased...
 
rsilverst said:
would the hum be there with it disconnected if it were the cables? i'm not sure... i guess if the cables are an antenna, then it should, huh...

when i set it to consumer, i still hear the hum. when i mess around with the cables and power cords, etcetera, the hum can be increased or decreased...
Click to expand...



there you go. Cheap cables can give you problems.
 
what are your cables close to? you could definitely get electrical interference or something of that nature. You said moving them around increases and decreases correct? So it could be it increases when you move it closer to something...

edit: so what i'm saying is that it might not be that they are cheap, although more shielding would help but possibly not eliminate the problem
 
i guess i'd like to know what kind of cables i *should* get.

ultimately, here's what i need to connect:

output side:

1. RCA from Delta 1010LT to 1/4" (either TS or TRS) on Presonus HP4 headphone/monitor mixer.

2. 1/4" TRS on Presonus HP4 to 1/4" TRS on KRK RP-5

input side:

1. RCA from Delta 1010LT to 1/4" on Line 6 PODxt (not sure if it's TS or TRS)

2. XLR from Delta 1010LT to XLR on ART Tube MP

3. XLR from ART Tube MP to microphone

Obviously, for the XLR connections, I'll just use XLR microphone cables, but I don't know what brand/type of cable to get for the other connections to minimize/eliminate the hum. Happy to hear suggestions.

Thanks!!
 
A few ideas from a fellow noise chaser

I'd go back to the beginning with the signal path and try to find out how many of these can be configured as balanced connections. Although balanced cables have three conductors (either XLR or TRS), it's not the cable that makes a balanced signal. It's the manner in which the signal is generated and received.

Balanced signals have the hot signal split into two parts, one of which is rendered in reverse phase to the other. Both hot conductors pick up static and hum along the cable run in the same way. (Longer cables = more potential for interference). However, at the destination, one hot line is again reversed in phase so the two are now in phase, and the two are then joined. That means the interference on that conductor is also reversed in phase and when joined with its "polar opposite" the two interference signals cancel each other out: the result is silence. That's the reason balanced cable runs are so much preferred over the alternatives.

If you have long unbalanced runs, think about inserting a small preamp or other device that will convert to a balanced signal and create a balanced cable run to the balanced inputs on the monitors. If you still have a hum there may be a house wiring, static (motors nearby? funky heating system kicking in? next door to police or radio station?) or computer grounding issue, or perhaps an issue with the monitor.

You can also test the house outlets for proper wiring connections - such as for polarity and a working ground - with a five dollar plug in tester available at any hardware store. Sometimes outlets are wired backwards and all hell can break loose.

Finally, try to route your power cords so ultimately everything runs off the same single outlet. If there's a problem elsewhere in the house this will minimize the likelihood that it will seep into your signal path as noise.
 
I emailed a similar question to the people at KRK to see if they had any suggestions about the hum. They seemed to think straightaway that it was a ground loop and told me to buy a couple of 2-prong to 3-prong converters and plug in both of my monitors through those. It seems like an inexpensive solution, so I may try that. I'm not sure why I'd have a loop though, since all my components are plugged into the same outlet.
 
A better soultion is to plug the monitors into the same power outlet as your computer, dont use the ground lift unless you really need to
 
altitude909 said:
A better soultion is to plug the monitors into the same power outlet as your computer, dont use the ground lift unless you really need to
Click to expand...

the monitors are already plugged into the same power strip as the computer. there is only one component in the computer system plugged into a different power strip, and that's one of my two video monitors. but even in that case, the power strip is going to the same outlet.
 
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