questions, questions....
Hi Guys,
Being also a proud owner of a Behringer DCX2496, I looked up some of the chips. The DAC is an AKM 4393. Now, this has a pincompatible upgrade, the 4395, which has a digital volume contron on the chip.
How about replacing the DAC and interfacing the volume control registers to an outboard PIC controller? Does anybody have experience with those integrated volume controls on DAC chips? Is there an impact on sound quality?
Jan Didden
Hi Guys,
Being also a proud owner of a Behringer DCX2496, I looked up some of the chips. The DAC is an AKM 4393. Now, this has a pincompatible upgrade, the 4395, which has a digital volume contron on the chip.
How about replacing the DAC and interfacing the volume control registers to an outboard PIC controller? Does anybody have experience with those integrated volume controls on DAC chips? Is there an impact on sound quality?
Jan Didden
Janneman,
I also have the DCX unit in question. My plan is to replace the entire DAC chip with something better. Luckily, there is no internal volume setting in the DAC chip itself, so a simple graft seems very appropriate.
For me, the optimal unit seems to be TI PCM1794 in mono mode, and possibly several such units in parallel ...
For volume I am using Apox SHM in balanced mode shorting phase to phase.
May I suggest you consider doing the same
Petter
I also have the DCX unit in question. My plan is to replace the entire DAC chip with something better. Luckily, there is no internal volume setting in the DAC chip itself, so a simple graft seems very appropriate.
For me, the optimal unit seems to be TI PCM1794 in mono mode, and possibly several such units in parallel ...
For volume I am using Apox SHM in balanced mode shorting phase to phase.
May I suggest you consider doing the same
Petter
Schematics
I have two units and I do not regret buying them.
From my point of view the D/A section is not so bad. I coud point a couple of "proffessional" devices here, costing several K, that sound worse.
What I did was, like previously suggested by another poster, cleaning the supplys, adding decoupling capacitors and that improved the sound a bit.
I;m happy with the units but I'm ready to jump and do any mods to improve them.
How difficult would be to get the schematics? Do Behringer sells a "tech manual" or something like that?
®®
I have two units and I do not regret buying them.
From my point of view the D/A section is not so bad. I coud point a couple of "proffessional" devices here, costing several K, that sound worse.
What I did was, like previously suggested by another poster, cleaning the supplys, adding decoupling capacitors and that improved the sound a bit.
I;m happy with the units but I'm ready to jump and do any mods to improve them.
How difficult would be to get the schematics? Do Behringer sells a "tech manual" or something like that?
®®
Measurements done by this guy:
http://users.pandora.be/airborne/dcx.htm
suggest that the high pass filter levels out at - 40 Db in the mid and bass range.
Can anybody confirm these measurements ?
Anything to report on actual experinces using this device or/and modifications. ?
The Danish magazine "High Fidelity" had a test of the unit in their latest number. They regarded the D/A section of the unit to be of high quality, but not high end.
Morten
http://users.pandora.be/airborne/dcx.htm
suggest that the high pass filter levels out at - 40 Db in the mid and bass range.
Can anybody confirm these measurements ?
Anything to report on actual experinces using this device or/and modifications. ?
The Danish magazine "High Fidelity" had a test of the unit in their latest number. They regarded the D/A section of the unit to be of high quality, but not high end.
Morten
Pw SP
Jan,
Right now is running from the SMPS. I did a fast swap with a linear supply and didn't notice any improvement. Granted, that linear supply was a very simple one, with 3 leg regulators and a few bypass caps (pretty basic), so I returned to the midly modified original SMPS.
I'd really like to get some schematics for this unit in order to do a more in deepth mod.
®®
janneman said:
Jan,
Right now is running from the SMPS. I did a fast swap with a linear supply and didn't notice any improvement. Granted, that linear supply was a very simple one, with 3 leg regulators and a few bypass caps (pretty basic), so I returned to the midly modified original SMPS.
I'd really like to get some schematics for this unit in order to do a more in deepth mod.
®®
Get the digital signal out ...
Find the DAC chip
Find the datasheet for that chip
Take the digital input to this chip and feed it out. It will be 3 clock signals sounding like: MCLK, BCLK and L/RCLK
Work backwards to find out what the DSP is outputting
Figure out how to make the desired output, bearing in mind a triplet of signals as above is better than the Manchester encoded S/PDIF
With a schematic it is easier ...
Petter
Find the DAC chip
Find the datasheet for that chip
Take the digital input to this chip and feed it out. It will be 3 clock signals sounding like: MCLK, BCLK and L/RCLK
Work backwards to find out what the DSP is outputting
Figure out how to make the desired output, bearing in mind a triplet of signals as above is better than the Manchester encoded S/PDIF
With a schematic it is easier ...
Petter
I find the most expedient solution is to use a dip switch or jumpers to set the receiver's input format. As long as they aren't using some kind of packed DSP mode (Check the chip's datasheet to see if that DAC even supports that) then there aren't that many options and you are guaranteed to find success. Probably they are just using I2S.
If you have a scope you can also determine the digital format by inspection.
If you have a scope you can also determine the digital format by inspection.
Here is a link to the data sheet for the AKM AK4393...
http://www.asahi-kasei.co.jp/akm/en/product/ak4393/ek4393.pdf
To learn more about the format used between the DSP and AK4393, you could simply probe pins 12-14 to determine which of the 5 suppproted modes is used--I'd guess mode 3 (I2S). In addition, you could probe pin 9 to see if it is running in DFS mode (which suggests a sample rate of 96kHz).
It looks like a 3.3v part, so (assuming you want SPDIF) the simple solution is a 3.3v transmitter (CS8406?). If it is running at 96kHz and you have a DAC that supports only 44.1 or 48, then you'll need to throw a sample rate converter in the mix... I think CS makes a sample rate converter and transmitter combo. With a sample rate converter, and some jumpers, you could easily change the output sample rate later.
Is there anyone with a DCX2496 that could probe the circuit and report back?
Also, is there anyone seriously considering adding SPDIF output to their DCX2496?
Thanks!
http://www.asahi-kasei.co.jp/akm/en/product/ak4393/ek4393.pdf
To learn more about the format used between the DSP and AK4393, you could simply probe pins 12-14 to determine which of the 5 suppproted modes is used--I'd guess mode 3 (I2S). In addition, you could probe pin 9 to see if it is running in DFS mode (which suggests a sample rate of 96kHz).
It looks like a 3.3v part, so (assuming you want SPDIF) the simple solution is a 3.3v transmitter (CS8406?). If it is running at 96kHz and you have a DAC that supports only 44.1 or 48, then you'll need to throw a sample rate converter in the mix... I think CS makes a sample rate converter and transmitter combo. With a sample rate converter, and some jumpers, you could easily change the output sample rate later.
Is there anyone with a DCX2496 that could probe the circuit and report back?
Also, is there anyone seriously considering adding SPDIF output to their DCX2496?
Thanks!
Hi
I just receive this new wonder - DCX2496, but have problems with the levels.
I use it with the digital input on A directly from the digital output from a Teac vrds 10.
Most of the times the level meters go up in the red on the inputs and on the outputs I have to lower the level up to 9 dBs before clipping.
My questions is how do others use the digital input and is it possible to lower the digital level?
br
I just receive this new wonder - DCX2496, but have problems with the levels.
I use it with the digital input on A directly from the digital output from a Teac vrds 10.
Most of the times the level meters go up in the red on the inputs and on the outputs I have to lower the level up to 9 dBs before clipping.
My questions is how do others use the digital input and is it possible to lower the digital level?
br