is there a simple way to modify single ended digital out from a CD player/Transport to balanced out?
The cheap way is to just to use a 75 Ohm to 110 Ohm digital audio transformer -
Canare BCJ-XP-TRC 75 Ohm to 110 Ohm Digital Audio BCJ-XP-TRC B&H
But this does not fully adapt the s/pdif signal to true AES3 standard, and might not work in all cases.
The proper way to do it is with an active converter, such as the Hosa CDL-313
S/PDIF Coax to AES/EBU - Digital Audio Interface | Hosa Cables
$110 from Sweetwater.
Canare BCJ-XP-TRC 75 Ohm to 110 Ohm Digital Audio BCJ-XP-TRC B&H
But this does not fully adapt the s/pdif signal to true AES3 standard, and might not work in all cases.
The proper way to do it is with an active converter, such as the Hosa CDL-313
S/PDIF Coax to AES/EBU - Digital Audio Interface | Hosa Cables
$110 from Sweetwater.
I have a Marantz CD63 which I modded a few years ago. This uses an SAA7345GP for digital decoding. Would it be possible to hack this to provide the correct feeds?
Or would I use the SM5872 Digital filter and D/A converter chip to provide the balanced out? Or the TDQ1301 digital servo control?
I have looked at the service manual and can't seem to find the part of the schematic relating to Dig Out, only the Analog Outs.
Or would I use the SM5872 Digital filter and D/A converter chip to provide the balanced out? Or the TDQ1301 digital servo control?
I have looked at the service manual and can't seem to find the part of the schematic relating to Dig Out, only the Analog Outs.
Now that you mention a specific CD player, and the fact that you are prepared to do internal mods, I see the same mods were discussed on this forum back in 2007 -
Marantz CD63 with AES/EBU output mods
You will see that the final suggestion in that thread was just to use an RCA-to-XLR adapter cable - which is possibly acceptable because the CD63 s/pdif output circuit includes a transformer.
However I feel the original modifications suggested by forum member Will have merit, and that would be a good starting point for as-close-to-AES3 output as possible.
Yes, that's why I think Will's suggestion to increase the voltage of the s/pdif signal is sensible. I don't know how to calculate the correct resistor values to achieve 5Vpp - Will suggests to completely remove RT01 and RT02?
At the moment I am using a Supra Cables AES/EBU to RCA converter taking the RCA from the 63 through the converter to the AES/EBU Dig In of a Behringer Ultramatch. The source indicator shows the input as "Digital" and not AES/EBU. I would like to try it in fully balanced mode.
Well at the outset I note that you have a working solution to connect the CD63 to the Ultramatch. That's a win.
There are some good circuits here to interface s/pdif to AES3 -
epanorama.net/S/PDIF Interface
But this is adaptation, not conversion. I think the situation is explained in one particular paragraph of that webpage -
It seems to me that no matter what circuit modifications you do to the CD63, the DOBM signal leaving the SAA7345 chip is not AES3 standard.
So what next? You could try to install a true AES3 transmitter chip/circuit in the CD63 - but I think you would need to access I2S signals (DATA, WCLK, SCLK) from the SAA7345 chip. Feasible, but non-trivial.
The other option is to use external hardware to decode the s/pdif, then re-encode as AES3 ... as the Hosa CDL-313 active converter does.
Or a final option is to be happy with your present working system!
Thanks very much for your detailed response Linux. It had initially thought when pondering this matter was whether I could add something like a CS84** taking the feed from somewhere on the 7345 to provide a differential input...However...
UPDATE:
As I mentioned earlier I had been using a converter on what I thought was the DIG IN....(by the way...don't get old and stupid!) After getting properly to the rear of the Ultramatch I saw that it was on the OUT!
The signal in was by and XLR to RCA I obviously made years ago when I got the UM to get the thing going.
So...I changed a few things around and now have the Dig In AES/EBU signal light on by using the Neutrik digital transformer (not Supra....that is the XLR cable make!) So I am there. Moral of the story...don't assume anything or rely on your memory, well not mine anyway.
UPDATE:
As I mentioned earlier I had been using a converter on what I thought was the DIG IN....(by the way...don't get old and stupid!) After getting properly to the rear of the Ultramatch I saw that it was on the OUT!
The signal in was by and XLR to RCA I obviously made years ago when I got the UM to get the thing going.
So...I changed a few things around and now have the Dig In AES/EBU signal light on by using the Neutrik digital transformer (not Supra....that is the XLR cable make!) So I am there. Moral of the story...don't assume anything or rely on your memory, well not mine anyway.
Attachments
Last edited:
OK, good to hear.
Yes, your Neutrik transformer - which is a direct equivalent of the Canare transformer I mentioned in post #2 - presents a true balanced signal to the Ultramatch.
With this final configuration, a final suggestion - now that you have added a Neutrik transformer to the digital signal chain, the CD63's s/pdif output transformer is not needed, and if you bypass it I think you will have a slightly stronger s/pdif signal arriving at the Ultramatch, and the shape of this s/pdif signal's square pulses will be less messed up!
Yes, your Neutrik transformer - which is a direct equivalent of the Canare transformer I mentioned in post #2 - presents a true balanced signal to the Ultramatch.
With this final configuration, a final suggestion - now that you have added a Neutrik transformer to the digital signal chain, the CD63's s/pdif output transformer is not needed, and if you bypass it I think you will have a slightly stronger s/pdif signal arriving at the Ultramatch, and the shape of this s/pdif signal's square pulses will be less messed up!
The schematic I found online for the CD63 is the same that was posted here -
Marantz CD63 with AES/EBU output mods
But I see there are different versions of the CD63 - mkII, SE, etc. Just open the lid and have a look.
Marantz CD63 with AES/EBU output mods
But I see there are different versions of the CD63 - mkII, SE, etc. Just open the lid and have a look.