Need Help on Denon DCD-S10

[Noak]

hi all,

I've purchased a used Denon DCD-S10 a while ago and I'm itching to get it modded. First and foremost, can anyone kindly share with me the service manual for this player? I've called my local Denon Service Center but they no longer have the service manual.

Meanwhile, I'm getting kinda confused when I looked at the DAC and analog output stages. The S10 has 3 types of outputs, fixed RCA, variable RCA (output controlled thru headphone's volume knob) and balanced output.

There are 4x PCM1702 DAC, the Iout of each going into a NEC C4570C dual opamp. However, only one of the dual opamp is used in each case. The output of the C4570C goes to another C4570C (again only one opamp used) which then splits the output to a NEC C4570C and a BA15218. The final NEC C4570C goes out to the fixed RCA output. I'm not sure if that's the right flow, I guess I will have to trace out the entire board.

I'm looking at replacing the opamps as a 1st level mod (with dual opamps to make things easier) perhaps with OPA2227, OPA2228, AD826, AD827 ... Any suggestions?

[anatech]

Hi Noak,
I have a DCD-S10. A very under rated CD player. Each channel uses a pair of PCM1702's in opposition. They are already co-linear DACs.

I haven't bothered to modify it yet. I don't want to spoil the sound, but I may consider it.

So what do you think of the sound?

-Chris

[Noak]

hi anatech,

I've modified my PD-S802 and I really like the sound I've got so I'm using that as a reference for the DCD-S10.

I'm impressed with the representation of depth, soundstage and its imaging but the midrange is slightly grainy and body is slightly lacking. Bass is also slightly loose and weak and extension is limited. The decay is not really present. On a whole, the music did not manage to attract me in the way that my S802 did.

I looking to improve the bass, perhaps a smoother midrange sound and probably a sweeter high as well. I'd used the OPA627s (I/V and output stages) in my S802 to great effect and I will probably do so likewise.

What do you think about the sound then?

Rgds,
Marc

[Noak]

For a start, I would suggest changing all the NEC C4570C dual opamps and replace with DIP8 sockets so that you can try "opamp-rolling".

[BerntR]

Originally posted by Noak
hi all,

Meanwhile, I'm getting kinda confused when I looked at the DAC and analog output stages. The S10 has 3 types of outputs, fixed RCA, variable RCA (output controlled thru headphone's volume knob) and balanced output.

There are 4x PCM1702 DAC, the Iout of each going into a NEC C4570C dual opamp. However, only one of the dual opamp is used in each case. The output of the C4570C goes to another C4570C (again only one opamp used) which then splits the output to a NEC C4570C and a BA15218. The final NEC C4570C goes out to the fixed RCA output. I'm not sure if that's the right flow, I guess I will have to trace out the entire board.

I'm looking at replacing the opamps as a 1st level mod (with dual opamps to make things easier) perhaps with OPA2227, OPA2228, AD826, AD827 ... Any suggestions?

Congrats on your S10. I've had one for more than 10 years, and I still like it. IMO, the analog circuitry is a weakness with the S10. The signal is simply passing through too many opamps, resistors and capacitors for it's own good. And for the balanced output - and for the variable outputs it gets even worse. One thing is that the path is more complex than needed, another thing is that it gets quite expensive to replace so many opamps and passive compnents.

The first opamp is iv conversion, the second one is + and - addition, the third and forth is buffering combined with filtering if I recall correct.

I bought and installed a class a analog buffer stage on a small pcb together with separate power supply. It has iv capability.

I broke the signal path just after the dacs by removing resistors. And basicaly using the resistor's pcb holes to connect the buffer. Using both dac's for both channels gave me a balanced input to the new buffer stage.

The buffer also has balanced output, so I now have a full balanced solution.

I used a buffer stage from LC Audio, but there are probably other good candidates as well.

I totally replaced the balanced pcb's with neutrik chassis connectors. I also rewired the variable output to the new pcb.

It works very well.

Edit: I've also installed a clock upgrade with separate ps.

[Noak]

hi BerntR,

I really like the looks of the Denon and I do agree that the signal has passed through too many opamps. Only a single opamp of the C4570C is used and I think it's a compromise between cost and sound quality.

Currently, I do not have the intention of using another 3rd-party analog stage so I would try my best to optimise the analog stage. Thanks for confirming what I suspect with regards to the I/V, adder and output buffer stages.

BTW, there are 2 oddly shaped capacitors placed between the Elna Silmics with something "SA....". Do you know what that might be?

[BerntR]

Originally posted by Noak
hi BerntR,

I really like the looks of the Denon and I do agree that the signal has passed through too many opamps. Only a single opamp of the C4570C is used and I think it's a compromise between cost and sound quality.

Currently, I do not have the intention of using another 3rd-party analog stage so I would try my best to optimise the analog stage. Thanks for confirming what I suspect with regards to the I/V, adder and output buffer stages.

BTW, there are 2 oddly shaped capacitors placed between the Elna Silmics with something "SA....". Do you know what that might be?

Noak,

I have the service manual right in front of me now. I haven't looked at the board itself lately, but I guess the Silmic's are series coupled at the output?

The following series are parallell coupled at the output:

1) 470+470 (silmic's i presume)
2) 2,2+2,2 (physically between the two pairs of silmics). If you have multi voltage model, these can be 4,7+4,7.
3) 1 (asian model only)
4)0,01 (asian model only)

So it's basically a dc block with large caps bypassed by small value caps.


btw, the IC 309 and 310 are not directly in the signal path. I suspect they handle high freq. filtering, but am not sure.

[Noak]

hi BerntR,

Yes, the Silmics are series coupled and thanks for sharing the information. You are very lucky to have the service manual. I've tried every source I know of but they replied that it is no longer available.

The caps I was referring to weren't Silmics, they look like elongated hexagons, something I've never come across till now.

Some questions for you:

1. The Iout of PCM1702J goes to a single opamp of the C4570C and the other is left un-used, is that right?

2. Outputs from 2 of the I/V stages are added together using another C4570C, again only one of the opamp is used and not both, is that correct as well?

3. The output from the "adder" splits to 2 different dual opamps, a BA15218 and a C4570C. Any idea why BA15218 was used instead?


If you don't mind, I'll be asking more questions later on but it's getting late here in Singapore so I'm off to bed now.

I can also be reached at marc.noak@gmail.com

Cheers and Thanks Again!!!
Marc

[A 8]

Slightly ot..but which digital filter is used in this player?

Thx/Michael

[BerntR]

Originally posted by A 8
Slightly ot..but which digital filter is used in this player?

Thx/Michael

Does this answer your qestion?

20 bit 8x oversampling. Alpha processing