Behringer DCX2496 digital X-over

well we are in the sunny south.. I really appreciate the offer because i sure would take you up on it..
It has been a year and half of total frustrations , denials, and still dont' have a working analog system!

I cant even get an answer as to which input pins are what! I can only go by the cable construction guide and assume!

I think it's in the ground architecture because i can run a 2 plug chassis input form my tuner and not have an issue but then again my tuner doesn't have balance controls and is only SE out.
 
Need help with Jan Didden passive output board

Hi all, I need your help.

I have stuffed and installed the Jan Didden passive output board. Channels 1-4 work correctly. 5 and 6 are somehow shorted, hence don't play music!

I read 1900 Ohm between the + and - on the channel 5 & 6 input pins on the board (no connection when testing the pins on the channels that do function).

Checked everything, and as far as I can see all is build by the book! So please help me if you can. A picture is attached and the faulty pins are marked with arrows.

Thank you,
Peter
 

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Found the problem, but what is the root cause?

Found out that both caps directly behind the xlr plug are working like wire (0 ohm resistance)?? Thus shorting the output. Removing them gives me the same resistance on all 6 channels.

Now what is the root cause? Can't believe I have had the bad luck of 2 faulty caps and that those are in the same spot on the pcb?

What could be the reason I blew them?

Hope I did not damage my DSP board.!
 
Now what is the root cause? Can't believe I have had the bad luck of 2 faulty caps and that those are in the same spot on the pcb?

Could well have been a bad batch.

What could be the reason I blew them?

My main suspicion is still a bad batch of caps. For a cap to go into a short circuit, you usually need an overvoltage leading to a breakthrough in the isolating material, but I have also seen similar effects from heat.
 
AX tech editor
Joined 2002
Paid Member
Found out that both caps directly behind the xlr plug are working like wire (0 ohm resistance)?? Thus shorting the output. Removing them gives me the same resistance on all 6 channels.

Now what is the root cause? Can't believe I have had the bad luck of 2 faulty caps and that those are in the same spot on the pcb?

What could be the reason I blew them?

Hope I did not damage my DSP board.!

Are they actually shorted? Did you check after you removed them?

jan
 
All thank you for the input.

Will put new caps in next week!

One more question, I have put a 332 ohm resistor on the digital in transformer and took out the 110 ohm one (I have installed toslink, and run Spdif directly to the PCB).

Now the digital in fluctuates between as should and highs muted?? Never had this before. It becomes worse if I manipulate the toslink cable :confused:

Could this be an echo problem? There was some discussion whether you needed to replace with 75 ohm or with higher values (between 200 and 500 was suggested).

If it is not the echo problem, I suspect that my Cirrus chip did not like some of the work I did this weekend :eek:
 
................................., I have put a 332 ohm resistor on the digital in transformer and took out the 110 ohm one (I have installed toslink, and run Spdif directly to the PCB).

Now the digital in fluctuates between as should and highs muted?? Never had this before. .................
Is the line 75ohm or 110ohm?
You must terminate the line with the correct impedance.
Is the line at the send end also correctly terminated?
 
Yet another DCX2496 mod...

List of changes:
1. Changed all big caps in the PSU to Panasonic FC
2. Added small local caps for DACs and opamps in the analog-out board
3. Replaced 4396 DACs to 4396
4. Replaced all analog-out opamps to NE5532 (I just like them)
5. Bypassed the signal electrolytic in the unbalanced portion of the output. Output DC was not hurt.
6. Changed some gain-setting resistors around first two opamps in the analog section to lower gain to about 1. Net effect is that full scale output should be ~2Vrms on each leg of the XLR. Much more manageable in home environment.

Changes are color coded in pink in the pictures. I'd like to hear comments :)
 

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Thank you in advance... I have a unit that has suddenly started to
malfunction... Here is what I have been through:
1. Channel 4 started to intermittently trip my amps protection circuit
2. I opened the unit up and while operating it (music playing) I wiggled the
ribbon cable to the output board (the large one) and heard what I've read on a
few forums as described "popcorn" or bacon "cooking"
3. I removed the ribbon cable from the harness on the output board and with a
scissors carefully cut off maybe 2mm of ribbon removing the original holes made
by the harness creating a "fresh area"
4. I used the plastic harness cover to press the new ribbon end (the fresh area)
onto the harness driving the sharp connectors up through the ribbon wires so it
is seated just like it came from the factory
5. I plugged all back in - All channels work fine - except - Channel 4 continues
to trip the protection circuit on the amp -- but -- when I wiggle the newly
seated ribbon the "pop corn" sound is GONE - so at least I cured that.

Question: I have decent soldering skills and I do own a decent meter, but how
MIGHT I go about debugging what might be wrong with Channel 4?

Thoughts? Suggestions? Thank you
 
Administrator
Joined 2004
Paid Member
1. Changed all big caps in the PSU to Panasonic FC
Yes, good idea. I used Panasonic FM, but either series are better than what's originally in there.
2. Added small local caps for DACs and opamps in the analog-out board
Also a good idea. I've found that this makes a big difference to perceived dynamics. I don't know why you left the leads long, I just pulled the original caps and replaced them with double the value Panasonic FM. Keep the leads short.
3. Replaced 4396 DACs to 4396
That sounds like a difficult change over. ;)
4. Replaced all analog-out opamps to NE5532 (I just like them)
Good idea. Even better is to do away with the opamps altogether and use a passive output. I like transformers, other people like caps. You might try lat later, to hear if you like it better.

Cleaning up the power and getting rid of the bad output stage will really transform the sound of the unit. Good work!
 
Hello, this is my first post to diyAudio.

Inspired by the linuxworks mod in last December, I put a WM8805 digital output board in my DCX2496.

Actually I bought a WM8805 DAI board from the following, and configured with the pins.

????Blog:DAI?????????????WM8805_G??????
(sorry they only have Japanese page.)

A level shifter, 3.3V AVR and a transformer were put on the small additional board glued with the board.

http://www001.upp.so-net.ne.jp/home-dir/pic/dcx2496/01.JPG
http://www001.upp.so-net.ne.jp/home-dir/pic/dcx2496/02.JPG

Since R3 (100ohm to DAC SDATA) decreased signal amplitude and WM8805 didn't work, I removed it. The above picture was taken before the removal.

Sound quality improved very much!

Next mod is to put a SRC&Clock from Pilgham Audio. I'm looking forward to playing with it.
 
Hey Owen,

would you like to elaborate on your announced 'Behringer DCX2496 Upgrade Board'? Here might be the right place to discuss the DCX related aspects of it, but I'm sure you'll also want to open a dedicated thread for the actual project itself.

I too am getting very frustrated about the DCX lately. I'm too cheap and time constrained to try other DSP platforms, but living with an (almost) stock DCX2496 really is a pain. :D

Thanks,
Sebastian.
 
Help on Linear AUDIO mOD

HELLO ,

I BOUGHT ONE OF THIS KITS ( LINEAR AUDIO ACTIVE, V3) A WHILE AGO AND STARTED IT BUT HAD LO LET IT ASIDE FOR LONG TIME. i RESTARTED COMPLETING IT NOW, BUT SOMEHOW LOST THE LIST OF THE COMPONENTS, SO NOW i DON´T HAVE AN IDEA OF WHAT VALUE IS R23 OR C11 OR WHAT IS U7 ON THE BOARD....

DOES ANYONE HAVE THE BILL OF MATERIALS WITH THE DESCRIPTION OF THE COMPONENTS AVAILABLE?

THANK YOU FOR YOUR HELP.,


FERNANDO
 
might start from output of chanel 4

Thank you in advance... I have a unit that has suddenly started to
malfunction... Here is what I have been through:
1. Channel 4 started to intermittently trip my amps protection circuit
2. I opened the unit up and while operating it (music playing) I wiggled the
ribbon cable to the output board (the large one) and heard what I've read on a
few forums as described "popcorn" or bacon "cooking"
3. I removed the ribbon cable from the harness on the output board and with a
scissors carefully cut off maybe 2mm of ribbon removing the original holes made
by the harness creating a "fresh area"
4. I used the plastic harness cover to press the new ribbon end (the fresh area)
onto the harness driving the sharp connectors up through the ribbon wires so it
is seated just like it came from the factory
5. I plugged all back in - All channels work fine - except - Channel 4 continues
to trip the protection circuit on the amp -- but -- when I wiggle the newly
seated ribbon the "pop corn" sound is GONE - so at least I cured that.

Question: I have decent soldering skills and I do own a decent meter, but how
MIGHT I go about debugging what might be wrong with Channel 4?

Thoughts? Suggestions? Thank you

Just a idea that channel 4 is sensing something there ,like a overload,I would disconnect that output and see if it's still acting up,if so,start from the out put backwards ,you got 5 other circuit's working,so compare what is there to each point,something will be different,look for heat problems and use your finger,and nose to see any thing has got hot,
The schematic is on yahoo groups(DCX2496) in the file section,I'm kinda leaning to a opamp going bad ,but find the fault ,I use a infrared temp meter ,it tells on components getting to hot,lol.
Also do a reset on the settings,just in case channel 4 was not set right, good luck,Post your results,and ask as you go ,lots of people to help you here!
:cheers:
NS
 
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