Marantz CD-54 Can it be NOSed?

[phildela]

Hi Guys,
I am a lover of 14 bit early CD players but I always NOS them because the sound quality is way better to my ears. So far I have done all the CD-104 derivatives, a CD-101 and a Marantz CD-74; but I can not get the CD-54 into NOS for some reason (I can hear music but a lot of white noise together, about 50/50).
I have compared schematics from the CD-104 to the CD-54 and I can see that LAT on the 54 goes straight from the CIM to the DACs, whereas on the 104 the LAT is derived from the SAA7030 filter. Therefore I have used three straps instead of four in the NOS mod (DLFD, CLFD, DRFD) - This should in theory work but it doesn't!?
Can anybody tell me what I'm doing wrong?
Thanks very much.

 

[batteryman]

Hi Guys,
I am a lover of 14 bit early CD players but I always NOS them because the sound quality is way better to my ears. So far I have done all the CD-104 derivatives, a CD-101 and a Marantz CD-74; but I can not get the CD-54 into NOS for some reason (I can hear music but a lot of white noise together, about 50/50).
I have compared schematics from the CD-104 to the CD-54 and I can see that LAT on the 54 goes straight from the CIM to the DACs, whereas on the 104 the LAT is derived from the SAA7030 filter. Therefore I have used three straps instead of four in the NOS mod (DLFD, CLFD, DRFD) - This should in theory work but it doesn't!?
Can anybody tell me what I'm doing wrong?
Thanks very much.

For NOS you need the signals from the filter input, not the output as you are doing.
So connect to:
DLCF
DRCF
STR1
CLCF

 

[phildela]

Thanks for the reply, I am using the same 24 way socket with wiring I always use (successfully) but I removed the LAT strap. I quoted the DLFD etc just to say which lines were connected - It is the standard NOS mod that is used on the 104 in this forum and I have done it many times. On some players like the CD-73 and 74 you need to make an adjustment due to slight differences. The CD-54 looks like the 104 except for LATCH coming from CIM instead of filter.

 

[lcsaszar]

LE (2 x TDA1540P pin #2) should be strapped to STR1 (SAA7000 pin #12)

 

[lcsaszar]

See this description:

https://www.diyaudio.com/forums/digital-source/127279-saa7030-removal-help.html#post1574676

It seems the SAA7000 (concealment, interpolation and muting, CIM) pin #11 outputs STR2 176.4 kHz, pin #12 STR1 outputs 44.1 kHz. The latter is needed for the NOS mod to control the DAC chip LE Latch Enable signal.

 

[phildela]

Thank you very much your suggestion worked! Not sounding as good as a CD-104 though, so will try modifying the output stage. I also need to tackle the 54s refusal to play CDRs.