DCX2496 outputs, voltage divider for level control?
A little off topic, but as the OP I thought this may be a good place to post as it gives me continuity.
If i need to start a new thread, please let me know.
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I presently am using the digital output from my satellite receiver to feed the DEQ's S/PDIF input.
I also can hook up my CD player to the AES/EBU input, but my DVD player has only analog outs (figure that out later).
The DCX is fed from the DEQ with an AES/EBU cable and then the analog outputs to my amps.
I presently have to control levels at each amp
I will say that using the full output voltage from the DCX, and then attenuating at the amps does not sound all that bad.
It is however a pain in the.... .
I am trying to decide whether to buy the Pilgham 6 channel volume control or just do a cap output and some PS upgrades.
.
It really would be nice to have a 6 channel volume control.
It would also be nice if the volume control did not require major mods to the DCX so when the DCX inevitably smokes I can easily transfer the volume control to a new unit.
A capacitor output mod can be rather easily transferred but the Pilgham 6 channel volume control is not all that easy to transfer.
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I am running 2 top/midrange boxes, 2 mid bass boxes and plan to have 2 subs (only one now), so I will use 6 channels out of the DCX.
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I found a 6 gang, motorized, remote controllable ALPS potentiometer that was manufactured as a Hi-Fi volume control.
Does anyone see a problem using this as a voltage divider to control the output levels of the DCX 2496 ?
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The obvious way to do this would be to use it single ended, wiring the pot between + and ground, shunting - and taking the signal from the wiper of the pot.
I realize that I may have to use some (high quality) buffers to prevent the amp input impedance from entering into the equation.
.
I was thinking of making a 1 space rack mount box housing the volume control with XLR pigtails coming out to plug into the DCX and 6 chassis mount connectors for connecting amps.
I could also install some trimming potentiometers to balance all the channels.
.
I believe the DCX 2496 can tolerate the 10K load with no problems.
.
Any comments?
Dave
A little off topic, but as the OP I thought this may be a good place to post as it gives me continuity.
If i need to start a new thread, please let me know.
.
I presently am using the digital output from my satellite receiver to feed the DEQ's S/PDIF input.
I also can hook up my CD player to the AES/EBU input, but my DVD player has only analog outs (figure that out later).
The DCX is fed from the DEQ with an AES/EBU cable and then the analog outputs to my amps.
I presently have to control levels at each amp
I will say that using the full output voltage from the DCX, and then attenuating at the amps does not sound all that bad.
It is however a pain in the.... .
I am trying to decide whether to buy the Pilgham 6 channel volume control or just do a cap output and some PS upgrades.
.
It really would be nice to have a 6 channel volume control.
It would also be nice if the volume control did not require major mods to the DCX so when the DCX inevitably smokes I can easily transfer the volume control to a new unit.
A capacitor output mod can be rather easily transferred but the Pilgham 6 channel volume control is not all that easy to transfer.
.
I am running 2 top/midrange boxes, 2 mid bass boxes and plan to have 2 subs (only one now), so I will use 6 channels out of the DCX.
.
I found a 6 gang, motorized, remote controllable ALPS potentiometer that was manufactured as a Hi-Fi volume control.
Does anyone see a problem using this as a voltage divider to control the output levels of the DCX 2496 ?
.
The obvious way to do this would be to use it single ended, wiring the pot between + and ground, shunting - and taking the signal from the wiper of the pot.
I realize that I may have to use some (high quality) buffers to prevent the amp input impedance from entering into the equation.
.
I was thinking of making a 1 space rack mount box housing the volume control with XLR pigtails coming out to plug into the DCX and 6 chassis mount connectors for connecting amps.
I could also install some trimming potentiometers to balance all the channels.
.
I believe the DCX 2496 can tolerate the 10K load with no problems.
.
Any comments?
Dave
attenuators
Davey,
That MSB attenuator looks very interesting.
I have been all over the internet looking for stuff like that, I guess Google doesn't work well.
.
RNMarsh,
EBAY, from a store called "Familygate"
No it's not about that incident with my family
6 10K pots with stepper motor, IR remote driver available
It has a D-log taper but who cares as it is not a fader, just a volume control.
Hope I can figure out how to wire it......Doh
.
Also, here is the analog equivalent of the MSB
Or should I buy 3 of these bad boys. Only $771 Each.
What people wont do for SQ.
Davey, thanks for the MSB link,
Dave
Davey,
That MSB attenuator looks very interesting.
I have been all over the internet looking for stuff like that, I guess Google doesn't work well.
.
RNMarsh,
EBAY, from a store called "Familygate"
No it's not about that incident with my family
6 10K pots with stepper motor, IR remote driver available
It has a D-log taper but who cares as it is not a fader, just a volume control.
Hope I can figure out how to wire it......Doh
.
Also, here is the analog equivalent of the MSB
Or should I buy 3 of these bad boys. Only $771 Each.
What people wont do for SQ.
Davey, thanks for the MSB link,
Dave
I’ve got a DEQ2496, date code: 0303. I bought it used, never been inside it. Its capabilities as a live device are of some merit, but all the filters may be generated in software elsewhere.
Referencing is all about absolute levels.
Single sine wave signal as digital is normalized to full bit depth, FFT spectrum is referenced to 0 dBFS. A two sine signal full scale signal will have two peaks at –6dB.
In your DacMagic, DEQ2496, to M-Audio Fast Track Ultra loop an IMD sideband –95dB could only be excessive from an electrical engineering standpoint. This is completely beyond limits of human perception, and orders of magnitude beyond performance of speaker transducers.
I’ve got an E-MU 0404 USB box that serves me fairly well. Manufacture specs are easy to duplicate/beat using loopback of analog out to analog in, microphone gain set to 0dB.
The output pot is adjusted for –1.0dB peak using 1kHz full scale sine fs 96kHz 24bit wave file. Resultant spectrum:
Zoom:
On surface E-MU is in same ballpark as DacMagic:
Fig.10 Cambridge DacMagic, Steep filter, balanced output, HF intermodulation spectrum, 19+20kHz at 0dBFS peak into 100k ohms, 24-bit data (left channel blue, right red; linear frequency scale). Stereophile pictures and captions
E-MU for comparison:
Zoom:
E-MU side bands aren’t much higher than DacMagic, but getting close to Davey’s excessive point!
With E-MU and DEQ2496 it is possible to set up ditital loop, and demonstrate bit perfect behavior, so it is possible to look at E-MU analog out, DEQ analog input pair, and look at DEQ analog output, E-MU analog input pair separately from E-MU, DEQ, E-MU analog loop.
The results are scary:
DEQ2496 analog input fed is by E-MU output, with same levels as for E-MU loopback with itself.
Digitally fed DEQ with analog output to E-MU: DEQ2496 output levels are higher, and lowering output from DAW and from DEQ utility menu produce similar results:
Not pretty.
Regards,
Andrew
Referencing is all about absolute levels.
Single sine wave signal as digital is normalized to full bit depth, FFT spectrum is referenced to 0 dBFS. A two sine signal full scale signal will have two peaks at –6dB.
In your DacMagic, DEQ2496, to M-Audio Fast Track Ultra loop an IMD sideband –95dB could only be excessive from an electrical engineering standpoint. This is completely beyond limits of human perception, and orders of magnitude beyond performance of speaker transducers.
I’ve got an E-MU 0404 USB box that serves me fairly well. Manufacture specs are easy to duplicate/beat using loopback of analog out to analog in, microphone gain set to 0dB.
The output pot is adjusted for –1.0dB peak using 1kHz full scale sine fs 96kHz 24bit wave file. Resultant spectrum:
Zoom:
On surface E-MU is in same ballpark as DacMagic:
Fig.10 Cambridge DacMagic, Steep filter, balanced output, HF intermodulation spectrum, 19+20kHz at 0dBFS peak into 100k ohms, 24-bit data (left channel blue, right red; linear frequency scale). Stereophile pictures and captions
E-MU for comparison:
Zoom:
E-MU side bands aren’t much higher than DacMagic, but getting close to Davey’s excessive point!
With E-MU and DEQ2496 it is possible to set up ditital loop, and demonstrate bit perfect behavior, so it is possible to look at E-MU analog out, DEQ analog input pair, and look at DEQ analog output, E-MU analog input pair separately from E-MU, DEQ, E-MU analog loop.
The results are scary:
DEQ2496 analog input fed is by E-MU output, with same levels as for E-MU loopback with itself.
Digitally fed DEQ with analog output to E-MU: DEQ2496 output levels are higher, and lowering output from DAW and from DEQ utility menu produce similar results:
Not pretty.
Regards,
Andrew
Thanks for the posting Andrew. It's good to see your results show the same shortcomings as mine do for the DEQ.
Anyway, as I said I have made some boards to improve the analog inputs and outputs of the DEQ / DCX and I've set-up a website to offer an upgrade service. Behringer Mods Home
Anyway, as I said I have made some boards to improve the analog inputs and outputs of the DEQ / DCX and I've set-up a website to offer an upgrade service. Behringer Mods Home
Standard v Modified picture of 1kHz sine show power line issues that I don't have:
My DEQ2496 as analog insert:
Evident in your setup are intermodulation components riding 1kHz. Likely present in original, but hidden by plot of mod results.
Two tone IMD doesn't reveal odd order components.
Three tone IMD (Bob Cordell) provides slightly more challenging signal, and more in band components:
Regards,
Andrew
My DEQ2496 as analog insert:
Evident in your setup are intermodulation components riding 1kHz. Likely present in original, but hidden by plot of mod results.
Two tone IMD doesn't reveal odd order components.
Three tone IMD (Bob Cordell) provides slightly more challenging signal, and more in band components:
Regards,
Andrew
Hi Andrew,
The power line issues are to do with grounding between the PC + soundcard and the DEQ. It will change in each persons setup. I think how well an output stage isolates itself from that noise is interesting to see though. The superior CMRR of the modded output stage is likely making the improvement.
The 1KHz side bands are interesting as I've seen them on all the DEQs I've measured, modded and un-modded. I think they are jitter. I'd like to know why yours doesn't have them!
The power line issues are to do with grounding between the PC + soundcard and the DEQ. It will change in each persons setup. I think how well an output stage isolates itself from that noise is interesting to see though. The superior CMRR of the modded output stage is likely making the improvement.
The 1KHz side bands are interesting as I've seen them on all the DEQs I've measured, modded and un-modded. I think they are jitter. I'd like to know why yours doesn't have them!
Side bands in your pictures appear about +/-150Hz; Could be 3rd harmonic of power supply. Yes, given Behringer, I am amazed that I don't have them.
Is DEQ2496 SMPS?
On another note; with DCX2496 how hard to get digital out, and clock synching instead of SRC input? Gotta be some DAC heads that would like this.
Andrew
Is DEQ2496 SMPS?
On another note; with DCX2496 how hard to get digital out, and clock synching instead of SRC input? Gotta be some DAC heads that would like this.
Andrew
Elektor ADC is good:
Audio ADC 2001 - ELEKTOR.com | Electronics: Microcontrollers Embedded Audio Digital Analogue Test Measurement
PCB is still available, and the CS5396 ADC can be found from ebay though costs a little bit (=> look for elsewhere). If 117 dB SNR and 48 kHz fs is not limiting youre artistic actions then use the cheaper CS5394 instead.
Sorry not to get back to this thread, I forgot about it.
I've modified both DCX and DEQ for simple transformer outputs. I just run the DAC differential outputs into a 1:1 or 1:2 transformer. It works great. Cinemag, Jensen, Sowter, Peerless, Onectics, whatever. I tune the peaking a little with a resistor across the transformer secondary. 3.3K is typical, but not critical. Gone is the edgy "Digital" sound that is so typical of bad digital equipment. The Stock outputs have, to my ear, a "ground glass in mud" sound. The transformer outputs remove the glass and the mud.
For power I have not done much, just replaced the cheap 25uF electrolytic caps on the +5V rails with 100uF Panasonic FM series - near the voltage regulator and near the DAC and ADC chips. They are they same size caps so fit no trouble. This seems to make a noticeable improvement in power and dynamics - I was surprised how much. I know others have done even more extensive PSU mods.
For the DCX analog inputs, I simply built my own analog section with high quality opamps and used the DCX +/-15V supply rails. The new section was either cap coupled or transformer coupled to the ADC chip. Sounds great, measures great. One could probably do better, but this seemed to work very well.
My results replacing the analog sections of the Behringer DEQ and DCX very much mirror what Barelywater has posted here. In fact, I used to do these mods for hire, but no longer offer them. They really aren't hard for most DIY'ers to do.
I've modified both DCX and DEQ for simple transformer outputs. I just run the DAC differential outputs into a 1:1 or 1:2 transformer. It works great. Cinemag, Jensen, Sowter, Peerless, Onectics, whatever. I tune the peaking a little with a resistor across the transformer secondary. 3.3K is typical, but not critical. Gone is the edgy "Digital" sound that is so typical of bad digital equipment. The Stock outputs have, to my ear, a "ground glass in mud" sound. The transformer outputs remove the glass and the mud.
For power I have not done much, just replaced the cheap 25uF electrolytic caps on the +5V rails with 100uF Panasonic FM series - near the voltage regulator and near the DAC and ADC chips. They are they same size caps so fit no trouble. This seems to make a noticeable improvement in power and dynamics - I was surprised how much. I know others have done even more extensive PSU mods.
For the DCX analog inputs, I simply built my own analog section with high quality opamps and used the DCX +/-15V supply rails. The new section was either cap coupled or transformer coupled to the ADC chip. Sounds great, measures great. One could probably do better, but this seemed to work very well.
My results replacing the analog sections of the Behringer DEQ and DCX very much mirror what Barelywater has posted here. In fact, I used to do these mods for hire, but no longer offer them. They really aren't hard for most DIY'ers to do.
Hi Guys,
I have a DEQ it was a for parts only deal,someone tried to remove ak4393,The right side traces are gone but the left side is still intact,so the right side has mostly outputs and some caps and power in,so how much trouble would it be to replace the dac with a WM8741 as I have read it 's better than the 4396,I have looked for a ak5396 to wm8741 sch but not located one yet,ANY suggestions are welcome!
The digital in and outs all work ,and the analog input,is good,
Does the ak5396 tie the analog to the digital circuits,I was also thinking that the 8741 has software filters and a volume control but I do not know how to fashion them yet!
Thanks alot,
NS
I have a DEQ it was a for parts only deal,someone tried to remove ak4393,The right side traces are gone but the left side is still intact,so the right side has mostly outputs and some caps and power in,so how much trouble would it be to replace the dac with a WM8741 as I have read it 's better than the 4396,I have looked for a ak5396 to wm8741 sch but not located one yet,ANY suggestions are welcome!
The digital in and outs all work ,and the analog input,is good,
Does the ak5396 tie the analog to the digital circuits,I was also thinking that the 8741 has software filters and a volume control but I do not know how to fashion them yet!
Thanks alot,
NS
Sorry, I thought that 1st image in post #28 was yours, I see it's not.
Basically I find that the stock outputs are pretty clean below ~1KHz, but generate more and more high order harmonics above that. A better output stage will not have those problems and sounds subjectively smoother and less fatiguing.
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