Hi All,
I have finally recieved my DCX2496 for use in my 3 way dipole project. A few nights ago i plugged my dvd player into the unit and played a CD only to hear the famous frying egg noise spitting out of my dynacos! I opened the unit to check for loose ribbon cable connections (found none) and also noticed that the new units have foam insulation between the boards and the bottom of the case (so nothing suspect there).
I phoned behringer the next day and their response was that the DVD player input is probably too hot and needs to be attenuated with a pre-amp. I also got a lecture on how the dcx is made for use with pro gear not home audio blah blah blah.
So, last night I placed my mixer (with levels turned right down) between the dvd and the unit and connected to a power amp with zero attenuation. Presto, frying egg noise is gone! However, now the input to the DCX is so low that the input LED indicators on the DCX do not even light up. Will this cause any problems with resolution? I also fear I could have a problem with hiss once i hook up my horns to the unit. Is there a better way to deal with this problem?
I have finally recieved my DCX2496 for use in my 3 way dipole project. A few nights ago i plugged my dvd player into the unit and played a CD only to hear the famous frying egg noise spitting out of my dynacos! I opened the unit to check for loose ribbon cable connections (found none) and also noticed that the new units have foam insulation between the boards and the bottom of the case (so nothing suspect there).
I phoned behringer the next day and their response was that the DVD player input is probably too hot and needs to be attenuated with a pre-amp. I also got a lecture on how the dcx is made for use with pro gear not home audio blah blah blah.
So, last night I placed my mixer (with levels turned right down) between the dvd and the unit and connected to a power amp with zero attenuation. Presto, frying egg noise is gone! However, now the input to the DCX is so low that the input LED indicators on the DCX do not even light up. Will this cause any problems with resolution? I also fear I could have a problem with hiss once i hook up my horns to the unit. Is there a better way to deal with this problem?
I doubt that a DVD player is capable of overloading the input of a DCX.
A quick check on the input meters will no doubt confirm that the signal level is OK.
Very likely you have disturbed the ribbon cable and this has stopped the output noise.
I bought a broken DCX with the frying egg problem, and the final cure involved me removing the ribbon cable completely, and hardwiring all the connections between the PCB,s
This cured the problem but is not a easy thing to do!
A quick check on the input meters will no doubt confirm that the signal level is OK.
Very likely you have disturbed the ribbon cable and this has stopped the output noise.
I bought a broken DCX with the frying egg problem, and the final cure involved me removing the ribbon cable completely, and hardwiring all the connections between the PCB,s
This cured the problem but is not a easy thing to do!
I plugged the DVD player back into the DCX directly without the mixer and the problem is still there.. SNAP CRACKLE POP! Level is showing around -30db so you are right, no overloading.
With the mixer back in everything works fine
The ribbon connectors on the new units are hot glued in place and feel well secured. I doubt this is the problem in this case. I have read about a problem with the CS8420 chip however i think is only when used with digital input?
With the mixer back in everything works fine
The ribbon connectors on the new units are hot glued in place and feel well secured. I doubt this is the problem in this case. I have read about a problem with the CS8420 chip however i think is only when used with digital input?
I have a DCX as well, one possible problem is the volume level of all the 6 channels o/p are way up(at its max) and also the inputs( I assume you use analog i/p) to DCX.
When I got mine I config. all the channels first before I connect the DVD. Rather than using the analog DCX inputs I recommend you use the digital o/p from DVD and plug into channel A into the DCX. Config channel A as digital. It sounds better this way.
When I got mine I config. all the channels first before I connect the DVD. Rather than using the analog DCX inputs I recommend you use the digital o/p from DVD and plug into channel A into the DCX. Config channel A as digital. It sounds better this way.
Is the noise limited to certain output sockets or is it all the outputs.
The 'frying noise' is usually limited to certain outputs.
If the noise is on all channels then it is probably an input connection problem.
How have you connected the DVD player to the DCX? Is pin 1 connected to pin 3 for unbalanced XLR input connection as per the DCX manual?
The 'frying noise' is usually limited to certain outputs.
If the noise is on all channels then it is probably an input connection problem.
How have you connected the DVD player to the DCX? Is pin 1 connected to pin 3 for unbalanced XLR input connection as per the DCX manual?
I'm lucky, so far no frying eggs for me.
Unless you have a faulty DCX, there is no way a consumer CD player will over drive it. As noted above, just look at the VU meters.
So there are a few things to do to troubleshoot this.
Unless you have a faulty DCX, there is no way a consumer CD player will over drive it. As noted above, just look at the VU meters.
So there are a few things to do to troubleshoot this.
- Your mixer does not cause the problem. Why? Are you running it in balanced?
- Set the mixer to unity gain. Check the VU meters on the DCX to see that they are the same as when you connect the CD player directly. Still have the problem?
- What is your connector/cable from the CD player to the DCX?
- Are your power amps wide open, or have you turned down the input volume? For best gain structure they should be at 12 o'clock or lower.
- Try the digital input. You'll have to buy or make an RCA to XLR connector. Beware the level going in digital, it will be max! (turn stuff down, first)
Inputs and channel outputs are set at 0 gain. Yes i am using analong input but I would like to try digital output. Excuse my ignorance but does the digital cable need an XLR jack into input A or can I use the XLR / RCA adaptor i have in there now? Have never used a digital cable before, dont even know what they look like! Digital output from my dvd player looks like a standard RCA fitting.
If i use digital input, will I need to attenute the signal between the DCX output and the amps?
I am using outputs 1 and 4 for testing. When muting output 1, the right speaker is fine, the left speaker spits out frying bacon. When I mute channel 4, left speaker still crackles (with audible distortion in the higher freq) but not as loudly as when output 1 is on. So most of the noise seems to be from channel 1, and alot less from channel 4.
Regarding the pins, I have no idea, I bought my adaptors from here. Is there any way I can find out the pin connections on the adaptors?
You can check them with an ohm meter. Most likely you will find that XLR pin 1&3 are tried to ground, XLR pin 2 is connected to the center of the RCA.
You might want to mute all inputs and outputs. Then unmute and check each channel 1 at a time. Use the same output cable! Is there a difference between the noise of each channel with nothing else happening? Is there any difference in noise with the channel you are testing muted or not muted?
That test will tell us a lot. Then we can proceed to others.
You might want to mute all inputs and outputs. Then unmute and check each channel 1 at a time. Use the same output cable! Is there a difference between the noise of each channel with nothing else happening? Is there any difference in noise with the channel you are testing muted or not muted?
That test will tell us a lot. Then we can proceed to others.
I have tried to set the mixer to the same level as the CD input using the VU meters and yes, same problem! So it seems the attenuation of the signal through the mixer is preventing the noise, not the mixer itself.
When I had the CD player input direct I attenuated using volume pot of my integrated amp. When I plugged in the mixer i turned the amp to 12 oclock and attenuted through the mixer.
Is there a lazy mans digital RCA to XLR cable i can buy?
Or maybe I should finally buy myself a soldering iron. I some times forget this is a DIY forum!I ran into what I think was digital clipping after I added a 6-channel analog volume control downstream of the DCX. Until then I was using the DCX for volume control, so the inputs would always be at around -10. Once I added the analog VC, I set all inputs and outputs to 0 (so I wouldn't 'lose bits'). The CD player has a digital connection to the DCX, and on 'hot' CD's, it would light up the yellow LEDs on the inputs (I think that's -3 or -5). Then my midrange drivers have about 8dB of EQ to handle the dipole rolloff. That's the channel that would clip the most easily, and it sounded like pops / crackling.
For me, setting the DCX's inputs to about -6dB took care of the problem. I hope I'm not losing too many bits by doing that.
I got some advice on this on another forum. I'm using an RCA 75 ohm digital cable from Monoprice, which goes into an RCA-BNC adapter, and then Markertek has AES/EBU - S/PDIF converters, which are BNC-XLR. You just need to pick the right male/female combinations so everything hooks up. This also takes care of the 75/110 ohm impedance issue (not sure exactly what that affects, but I've seen some people mod the DCX to accept S/PDIF).
For me, setting the DCX's inputs to about -6dB took care of the problem. I hope I'm not losing too many bits by doing that.
I got some advice on this on another forum. I'm using an RCA 75 ohm digital cable from Monoprice, which goes into an RCA-BNC adapter, and then Markertek has AES/EBU - S/PDIF converters, which are BNC-XLR. You just need to pick the right male/female combinations so everything hooks up. This also takes care of the 75/110 ohm impedance issue (not sure exactly what that affects, but I've seen some people mod the DCX to accept S/PDIF).
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I know you have said that the leads are securely glued down, but in my experience with the DCX 'frying bacon noise' the problem was with the 26 pin IDC header connected to the input PCB
This header is soldered in position and the cable clipped in.
If its new & faulty then try to get it replaced!
You would not be the first person to receive a faulty DCX...
Behringer Ultradrive Problems Poll - Speakerplans.com Forums - Page 1
This header is soldered in position and the cable clipped in.
If its new & faulty then try to get it replaced!
You would not be the first person to receive a faulty DCX...
Behringer Ultradrive Problems Poll - Speakerplans.com Forums - Page 1
panomaniac is right, just use the RCA to XLR converter cable and attach it to the terminal A.
How many bits does 6db equate to? And how many bits of loss would be noticable?
I know you have said that the leads are securely glued down, but in my experience with the DCX 'frying bacon noise' the problem was with the 26 pin IDC header connected to the input PCB
This header is soldered in position and the cable clipped in.
If its new & faulty then try to get it replaced!
You would not be the first person to receive a faulty DCX...
Behringer Ultradrive Problems Poll - Speakerplans.com Forums - Page 1
If it is the ribbon connector, im not sure why the noise stops when the input is attenuated. I'll play with it some more before shipping it back to behringer. I hate having to delay my project!
Thanks, Ill pick up an RCA digital cable from Jaycar today
Actually, im confused, can I just use the RCA cable i have now and plug that into the DVD players digital output and then run the cable to the XLR adaptor in DCX input A? Then set input A to digital on the DCX software?
Does the digital out from the DVD player output video as well as audio and will this be a problem for the DCX?
Thanks for your patience everyone.
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Yes, you can. There "may" be better ways to do it, but this will certainly work.
There is no video on that digital signal, no worries.
When you get the time to systematically test the DCX, you want to know if you have noise when there is no music playing (no signal). Test each of the 6 outputs for noise with no signal. Test for any difference with the channel muted or not. Also with inputs muted or not. That will be 4 tests per channel:
- Input + output muted
- Input unmuted, output muted
- Input muted, output unmuted
- Input + output unmuted
Seems like a lot, but it will go really fast. Keep notes!
What we are looking for is if you have any noise that is just coming from the DCX circuitry. If it is not, then it most be signal related. That's the next step.
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