Modding Denon DCD-1290

[ratep2001]

I have just bought a defect Denon DCD-1290, so I was thinking about repairing it as well as modding it a little bit. I couldn't find any useful information about the unit on the internet, only the one that it uses a multibit DAC (probably one of the PCMxxx Denon is familiar with)?

Does anybody have schematic / Service manual of the unit, so I don't work like blind? I would really appreciate it...

Any experience with modding this type of CD-player? I think I've come far with my Marantz CD-63 and the experience is highly positive, but I would certainly like to hear about some (even more spectacular) modding results of a multibit DAC.

Thanks in advance.

P.

[ratep2001]

I reparied my second-hand Denon DCD-1290 and now it plays fine. However, I must admit that I still prefer my modded Marantz CD-63mkII - it has much deeper and controlled bas, greater detail. Therefore I would like to try out similar things on the Denon, since it looks somewhat more robust in the chasis and the transport is much more quite, not to mention the multibit DAC.

I cannot find any datasheets about the DAC used - DIYaudio forum mentions NKS240A, although I don't remember seeing it - I think I saw some SMxxxx component and that reminds me on the Sigma-Delta DAC used in the Marantz. Anybody out there having the datasheet of NKS240A?

At the rear side there are two outputs: FIX and VARIABLE. I haven't got the scheme yet, so does anybody have an idea what is the difference?

I am still trying to find the DCD-1290 schematic, so if somebody has it you are very welcome to contact me.

P.

[rwa]

Hi,

I must have a schematical drawing somewhere,will search for it.
I own a special version called a EX its modified by van.Medevoort .
a dutch audio brand.

greats Rich

[ratep2001]

Hi Reach,

I read here that there is a specific Dutch version DCD-1290EX, but I don't understand why it was needed. Is it a modification that improves audio performance, or it is was just something need to fulfil some stringent dutch standards regarding EMC, safety, etc?

It would be great if you can find the schematic - I am looking forward to take a look at it.

Best regards,
Petar

[ratep2001]

I am just curious about what the two different outputs at the CD-player rear side do. There is one named "FIX" and another named "VARIABLE", and I can see that there is difference in the output level. The variable one has additional processing on the board, I found some opamps around it and another chip. I guess it is functioning as PGA, where the chip is maybe a set of different resistors to create different gains - or am I wrong?

I could probably understand this if somebody has the schematic and is willing to share it with me...

[singleended40]

Hi Everyone,

Have anyone tried to modify the Denon 2900? What parts should be replaced primarely? Thanks in advance.

[mosfet1]

hi there, some time ago I bought a denon dcd 1290 on Ebay for a little price : only 70 euros. The cd player came to me in very bad condition: display off, cd tray off, I was desperate for this!!!!
With patience I disassembly every parts of cd player, and after 5 hours of hard work
I see the first symphtom of life: display light on!!!
Now the cd player It's in perfect working order: sounds clear, detailed, introspective,very speedy.
The variable output seems to me to be the best of the two, I can drive the power amp with very good sound.
I can tell you that the tray looks as sony one, the weight it's about 8 kilos and the player has quality build.
If someone has service manual and other info please post here!!!!
thanks

[cviller]

Originally posted by ratep2001
I am just curious about what the two different outputs at the CD-player rear side do. There is one named "FIX" and another named "VARIABLE", and I can see that there is difference in the output level. The variable one has additional processing on the board, I found some opamps around it and another chip. I guess it is functioning as PGA, where the chip is maybe a set of different resistors to create different gains - or am I wrong?

I could probably understand this if somebody has the schematic and is willing to share it with me...

I have a Denon DCD-1015 which has these outputs too. I'm not completely sure how they are configured inside, but the difference is that you can adjust the output level with the variable, while the other is just fixed. Every time I turn of the power, it is reset to -10(dB?). I have noticed some static noise when using that output, so I think you should just ignore it.
I changed the opamps in mine and I think it improved the sound of strings, but I'm not sure...

[Piersma]

Hi all,

Quit a few years ago i have modded a Denon DCD1290 and this player still hangs around in my living room.
Here are the mods i have done.

Major improvements;

remove the muting transistors
replace the electrolytic output caps for MKT/MKP capacitors
replace the OPAMPs for OPA types
replace the filter caps for styroflex types

slight improvements;

replace te the (bad) voltage regulators for LM317/337 types
soft recovery diodes
100N decoupling caps for the IC circuits
separate +/- 12V power-supply for the OPA opamps


The "major improvement" mods are really worthwhile, just try it yourself !

[Mikhail]

I've made some mods too. As for me the best mod is proper supply as 1290 has a really bad one. I've added separate trans for digital and analog stages and decoupling caps+ferrite beads as well.

It's interesting that despite of announced true 20 bit DAC my exemplar has AD1861 that is 18 bit. But it also has -5v digital supply 8th leg of DAC chip so 20 bit AD1862 or another suitable DAC chip will work. this -5v digital is obtained from -6v analog... no good. Ground plane is also bad - has many loops on it. So separate DAC may be a better choice

I'm also wonder what is ALPHA chip that is declared on cover but absent on PSB...

BTW, had anyone got schematic?

Regards,
Mike