yes, i have been using the dcx to drive a triamped system for approx 10 years, and have just purchased the opc i/o board, as i i have long been aware the standard behringer output amps and circuitry, are not ideal.as the dcx is fed via aes from a deq 24/96 i would rather not fit the associated analogue input components if this wont raise noise and stability issues.
I have just soldered a board today. Hard bugger....
Guess i am not so used to solder SMD on big groundplane.
I think the Analog input has no interaction with digital input.
If you are an experienced solderer go ahead!
Maybe you should only solder inn source resistors, about 100ohms, to not have noise if you accidentally switches on analog.
The clics are muted at startup. Some low noise at swith off. Not just silece as original.
Guess i am not so used to solder SMD on big groundplane.
I think the Analog input has no interaction with digital input.
If you are an experienced solderer go ahead!
Maybe you should only solder inn source resistors, about 100ohms, to not have noise if you accidentally switches on analog.
The clics are muted at startup. Some low noise at swith off. Not just silece as original.
I got 3 output channels up OK. And 3 with some noise.
Don't know what the source of the noise is. Maybe to hot soldering, maybe some misalligned components. Be warned the LME differential opamp I used is a fiery beast (High bandwith, high current).
Small adjustments of components gives noise or takes it away.
This is the simplest possible configuration and not robbust regarding small user faults in component placing and soldering.
That said: If you get it working it is dead quiet and I can't hear the DCX with working channels anymore.
Don't know what the source of the noise is. Maybe to hot soldering, maybe some misalligned components. Be warned the LME differential opamp I used is a fiery beast (High bandwith, high current).
Small adjustments of components gives noise or takes it away.
This is the simplest possible configuration and not robbust regarding small user faults in component placing and soldering.
That said: If you get it working it is dead quiet and I can't hear the DCX with working channels anymore.
Hi opc,
A NICE board indeed !GREAT Work!
I have been fashioning a proto board myself,and this DCX output board is where I decided to cross over from Bal to SE,I used THAT 1512 for the outputs,and THAT1200 series for the inputs,I have the output proto board working and the DCX came to life and no noise,there is also a place to connect a volume control between pins 1 and 8,on 1512.
I am not a eagle cam guy but I would buy boards with SE outs if you would consider making changes ,and since this chip will put out almost 5 volts it works for a pre also,I went by the data sheet ,I did use higher (1.5K) to ground to limit it to almost clipping,
I will buy some of your boards ,I have another stock DCX and it will stay balanced,BTW I added a external PS LM317/337 and it stays it made a difference. I took all the grounds from X13(4) to the ps ground.
torgiers ,
You might take the 4 ground wires at X13, and separate the analog and digital with a resistor to gnd. and strap it with a .1 and .01 film to see if your noise goes away,
Just my 2 cents,
NS
A NICE board indeed !GREAT Work!
I have been fashioning a proto board myself,and this DCX output board is where I decided to cross over from Bal to SE,I used THAT 1512 for the outputs,and THAT1200 series for the inputs,I have the output proto board working and the DCX came to life and no noise,there is also a place to connect a volume control between pins 1 and 8,on 1512.
I am not a eagle cam guy but I would buy boards with SE outs if you would consider making changes ,and since this chip will put out almost 5 volts it works for a pre also,I went by the data sheet ,I did use higher (1.5K) to ground to limit it to almost clipping,
I will buy some of your boards ,I have another stock DCX and it will stay balanced,BTW I added a external PS LM317/337 and it stays it made a difference. I took all the grounds from X13(4) to the ps ground.
torgiers ,
You might take the 4 ground wires at X13, and separate the analog and digital with a resistor to gnd. and strap it with a .1 and .01 film to see if your noise goes away,
Just my 2 cents,
NS
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No problem at all. The analog input stage has no real impact on the output stages or the digital input.
For the sake of future proofing I would personally spend the $10 and the effort to build it all at once, but that's just me. There's no harm in leaving the analog inputs de-pop'd if you know you'll never need them.
Regards,
Owen
hi owen,many thanks,i found the schematic after i had posted my query.after years of "gain staging" and using my dvd-a source,as a limited volume control.i decided to try the 6 way alps pot, tracking warts and all.i have fitted 10k trimpots on the output xlr's,to compensate for amp sensitivity etc.from the data ,the alps is most linear between 150 and 280 degrees rotation and have started critical listening to see if the tracking errors are audible.first impession is the dynamic range has taken a massive leap,no doubt as the digital signal levels now run at close to 0db+
regards
regards
Thanks for your suggestions noSmoking.
I have put 4 x 2.7 nF C0G from +15 and -15 to ground in the area near C60.
X13 is the 26 pin in my DCX and it has only GNDA,
X14 has GNDA and GNDD
opc: I can't find where the DGND is going on the schematics (J12-11 and J12-12). Is it not connected anywhere?
The same with 5V J12-13
Because of my problems with noise (at -70dB) at some channels I have desoldered and soldered again some times, so now I'm not 100% sure of the health of the components....
Have to buy some new ones. Think I will go for the OPA1632 to simplify things.
In hindsigth I would have solder one and one channel, resistor and caps first, measured to check values and capacitance. Then soldered the opamp and measured.
May I ask how many degrees you have on the soldering iron to solder the caps to the groundplane?
Regards Torgeir
I have put 4 x 2.7 nF C0G from +15 and -15 to ground in the area near C60.
X13 is the 26 pin in my DCX and it has only GNDA,
X14 has GNDA and GNDD
opc: I can't find where the DGND is going on the schematics (J12-11 and J12-12). Is it not connected anywhere?
The same with 5V J12-13
Because of my problems with noise (at -70dB) at some channels I have desoldered and soldered again some times, so now I'm not 100% sure of the health of the components....
Have to buy some new ones. Think I will go for the OPA1632 to simplify things.
In hindsigth I would have solder one and one channel, resistor and caps first, measured to check values and capacitance. Then soldered the opamp and measured.
May I ask how many degrees you have on the soldering iron to solder the caps to the groundplane?
Regards Torgeir
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340°C to 360°C if the plane is pre-soldered (and pre-heated) where the connection is to be located.
If you try to do this from cold onto a copper ground plane, it seems to take forever with the serious risk of damaging the component. Most will tolerate upto 10seconds @ 300°C, adding a lead cooling clip will help, but only if there is room.
Thank you for the information, AndrewT. Think I was to sloppy on the preheating.
I have soldered a lot of other boards but none with this big groundplane = heatsink....
Doing some more measurements I see my problem is DC/spikes on the Vocm, in and out. mVolts to Volts that comes and goes (0.5 to 3 seconds)
Just have to search on.
Regard Torgeir
I have soldered a lot of other boards but none with this big groundplane = heatsink....
Doing some more measurements I see my problem is DC/spikes on the Vocm, in and out. mVolts to Volts that comes and goes (0.5 to 3 seconds)
Just have to search on.
Regard Torgeir
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I think it was due to caps with cold soldering to earth, but i'm not sure.
I have given up this board for a while. Can't get it stable.
And I have got a 5k ohm over R26 without any resistor. Maybe I have filled up some vias with tin or somthing. Can't get the resistance to go away.
(This is not a PCB fault, it is bad SMD soldering skills for this kind of board tolerances. Thought it would be easier to make the leap after 30 years of old fashioned soldering)
I have given up this board for a while. Can't get it stable.
And I have got a 5k ohm over R26 without any resistor. Maybe I have filled up some vias with tin or somthing. Can't get the resistance to go away.
(This is not a PCB fault, it is bad SMD soldering skills for this kind of board tolerances. Thought it would be easier to make the leap after 30 years of old fashioned soldering)
Hi, my name is Paul, I'm new to this forum. I'm from Germany and I'm a DIY-Audio hobbyist and also bought me a PA-soundsystem for private parties recently 
I am a new owner of a DCX2496 and I began to google about improvements of the DCX because I am not very satisfied with its acoustic performance.
1) I experience no issues with any annoying noise as outlined previously in this thread. I wanted to use the DCX as active crossover for my PA soundsystem. I have two RCF Art-712A 12" Fullrange Speakers which offer a impressively clear and detailed sound (compared to most other fullrange speakers in the same price range!) but also have a pretty high noise level even without any signal source connected to them. It made no noticable difference when I connected, disconnected or muted/unmuted the channel of the DCX to the Speakers.
Behringer seemed to redesign the DCX in some points, for example they removed the PCMCIA-slot. Maybe the also redesigned the internals of the DCX so the noise is not an issue anymore? (I will open it and post some pictures here soon if wanted)
2) I can't use it for my PA-Soundsystem. I totally agree with Points 3 & 4 of opc's entrance-post. The DCX is making the music sound dull and washy. It is somehow reducing the detail in the sound. Cristal-clearly shaped sounds sound very boring after the processing with the DCX. So the DCX is dramatically destroying all the features of high quality sound my expensive RCF Art Speakers offer. Therefore it's nearly useless for me and I think of sending it back to the merchant
My hope is now if someone can relate to this issue and can tell me if the Problems can be solved by replacing the input- or output-stage of the DSP. I really want to get high-end hifi-sound. It must not be noticable that the DCX is in the signal-path afterwards. Can anyone tell me if that is achievable (with acceptable effort) or if I'm better off sending it back, buy me an analog active crossover and abandon the features of a digital ls-management-system such as parametric equalizers.
Thanks for any help!
I am a new owner of a DCX2496 and I began to google about improvements of the DCX because I am not very satisfied with its acoustic performance.
1) I experience no issues with any annoying noise as outlined previously in this thread. I wanted to use the DCX as active crossover for my PA soundsystem. I have two RCF Art-712A 12" Fullrange Speakers which offer a impressively clear and detailed sound (compared to most other fullrange speakers in the same price range!) but also have a pretty high noise level even without any signal source connected to them. It made no noticable difference when I connected, disconnected or muted/unmuted the channel of the DCX to the Speakers.
Behringer seemed to redesign the DCX in some points, for example they removed the PCMCIA-slot. Maybe the also redesigned the internals of the DCX so the noise is not an issue anymore? (I will open it and post some pictures here soon if wanted)
2) I can't use it for my PA-Soundsystem. I totally agree with Points 3 & 4 of opc's entrance-post. The DCX is making the music sound dull and washy. It is somehow reducing the detail in the sound. Cristal-clearly shaped sounds sound very boring after the processing with the DCX. So the DCX is dramatically destroying all the features of high quality sound my expensive RCF Art Speakers offer. Therefore it's nearly useless for me and I think of sending it back to the merchant
My hope is now if someone can relate to this issue and can tell me if the Problems can be solved by replacing the input- or output-stage of the DSP. I really want to get high-end hifi-sound. It must not be noticable that the DCX is in the signal-path afterwards. Can anyone tell me if that is achievable (with acceptable effort) or if I'm better off sending it back, buy me an analog active crossover and abandon the features of a digital ls-management-system such as parametric equalizers.
Thanks for any help!
I couldn't help and just made two photos. Looks slightly different to me than everything I've seen beforehand. They seemed to merge the input- and output-stage to one board, which makes it rather complicated, when not rather impossible to chance specific parts of it
I think i will better send this one back. What a pitty.. the features of this DSP are nearly perfect for the price but the poor sound makes it completely useless to me.
I think i will better send this one back. What a pitty.. the features of this DSP are nearly perfect for the price but the poor sound makes it completely useless to me.
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