Marantz CD-17 measurements

[audio_tony]

Measurements of my slightly modified Marantz CD-17 (it's an early player so I think it's a MK1 or MK nothing lol).

In the audio section, The HDAM section has been removed, muting transistors bypassed and the OPAMPS replaced with NE5532 (I tried LM4562 but they were difficult to stabilise, and the sound was a bit harsh because of this).

Other mods include larger smoothing caps in the main PSU, and all OSCONS in the digital section. These mods were done probably 20 years ago now, but the player has seen little use. Imagine my surprise when opening the top cover to find two bulging caps (PSU section 2200uF 130degs C caps - Samwha branded so yes...).

My test setup: Asus Xonar STX sound card with a self built buffer / gain box in front of that. Host PC is an Intel i7 running Windows 10 with 32G RAM and SSD - no mechanical disks or CDROM drive present.
I also use an Altor Audio Olivine-2 ADC (which was used for these measurements).
Sound card input was set to 24bit/96kHz
REW was configured as per the recommendations in the post from @NTTY

 

[AnalogSteph]

Other mods include larger smoothing caps in the main PSU, and all OSCONS in the digital section. These mods were done probably 20 years ago now, but the player has seen little use. Imagine my surprise when opening the top cover to find two bulging caps (PSU section 2200uF 130degs C caps - Samwha branded so yes...).

That may have been a classic case of misimprovement. They were neither underrated nor installed backwards by mistake?

1 kHz has an unusually wide skirt, but I suspect that may be a windowing-related artifact rather than anything real.

BTW, I would encourage anyone doing this to always state their equipment / mesaurement setup as a matter of habit.

Had a look at the CD-17 service docs.
Which caps in particular did your bulging ones replace? I can see a pair of 3300µ/25V ones in unreg +/-16V, but that wouldn't have been an upgrade then. Maybe the two 470µ/16V ones on +/-12 V?

In the audio section, The HDAM section has been removed, muting transistors bypassed and the OPAMPS replaced with NE5532 (I tried LM4562 but they were difficult to stabilise, and the sound was a bit harsh because of this).

NJM2114 to NE5532? Isn't that, like, a downgrade? I always had the '2114 pegged as a 5532 on steroids.

Cool, a DAC7 combo with SM5841D digital filter, I wonder what that could do with @NTTY's shaped dither test tone.

The output stage looks quite similar to the TDA1547 datasheet suggestion except they left out the passive de-emphasis (which is done by the digital filter) and gave it some more gain. I somewhat have to frown at their combination of 10k/12k with 3.3k/3.9k, which is a nominal 1.5% mismatch in divider ratio from the outset... mind you, these were 5% resistors to begin with. 1/2 W chip, I'm guessing that's thick film?

This output stage design is a bit baffling in general to be honest... the insides of the DAC appear to be symmetrical but the next stage (bal/SE) clearly isn't, with different impedances on both legs and CMRR degradation in the treble (since the 56p has no counterpart on the lower leg). What did Philips know that I don't? (Maybe the NE5532's unbalanced input capacitances?) Or did they just suck at balanced receivers? Or were NP0 caps of ~150pF considered vastly too expensive?

 

[tmtomh]

20 years ago would put those replacement caps right in the middle of the Capacitor Plague, so probably just defective from the get-go.

 

[audio_tony]

That may have been a classic case of misimprovement. They were neither underrated nor installed backwards by mistake?

1 kHz has an unusually wide skirt, but I suspect that may be a windowing-related artifact rather than anything real.

BTW, I would encourage anyone doing this to always state their equipment / mesaurement setup as a matter of habit.

Had a look at the CD-17 service docs.
Which caps in particular did your bulging ones replace? I can see a pair of 3300µ/25V ones in unreg +/-16V, but that wouldn't have been an upgrade then. Maybe the two 470µ/16V ones on +/-12 V?

I have updated my post with my test setup.

The caps were definitely installed correctly as can be seen below - the originals were 1000uF - I have now changed them back to 1000uF.

The 3300uF caps were changed to 10000uF (probably unnecessary looking back...)

I have highlighted the changes in the schematic below. For what it's worth, I have struggled to find a schematic for this very early CD17.

NJM2114 to NE5532? Isn't that, like, a downgrade? I always had the '2114 pegged as a 5532 on steroids.

I tested those very NJM2114 opamps (that were removed from the CD17) and you can see they measure slightly inferior to the 5532.

I have wondered if it would be beneficial to add a second stage, and swap out the 5532's for NJM2043DD and the second stage (just a simple buffer) would use 5532s or even NJM2068DD

Link to the tests: https://gtkc.net/opamp-tests-into-a-2k7-load

As for the design decisions around the TDA1547.. As I said above, this appears to be a very early version of the CD17, and later revision schematics don't match the layout of my player.

 

[NTTY]

Cool, a DAC7 combo with SM5841D digital filter, I wonder what that could do with @NTTY's shaped dither test tone.

@audio_tony : File #23 of the latest Test CD for 0dBFS.

I can do the same with the Teac VRDS-20 over the course of the weekend (SM5840 and DAC7). The review needs a refresh anyways.

 

[AnalogSteph]

For what it's worth, I have struggled to find a schematic for this very early CD17.

So it's not one of the variants covered by the 1995 SM on HFE either?
74 CD17/01B/02B/02G
CD-17/ DFN/FB/FN/KBL/KGL

As if MkI - MkII - Mk3 wasn't enough already.

 

[audio_tony]

So it's not one of the variants covered by the 1995 SM on HFE either?
74 CD17/01B/02B/02G
CD-17/ DFN/FB/FN/KBL/KGL

I see a new manual has been added since the last time I looked (which was several years ago) - the '17/17D service manual' (74 CD17/01B/02B/02G) which looks closest to the player I have which is an 02B - but I'm confident the original caps were 1000uF (as per the schematic I posted) vs the 470uF stated in the 01B/02B/02G schematic you posted (and even in my maddest modding days, I wouldn't have gone from 470uF to 2200uF!!!).

It's also worth noting that the schematic I obtained at the time (which was a couple of gif files and incomplete) was labelled Philips CD17....?

 

[AnalogSteph]

It's also worth noting that the schematic I obtained at the time (which was a couple of gif files and incomplete) was labelled Philips CD17....?

Makes sense since Philips had the rights to the Marantz name from about 1980 (except US/CA 1990) until 2001. Philips still sold CD players into the mid-'90s under their own brand but all the higher-end offerings would be Marantz.

 

[audio_tony]

@audio_tony : File #23 of the latest Test CD for 0dBFS.

I can do the same with the Teac VRDS-20 over the course of the weekend (SM5840 and DAC7). The review needs a refresh anyways.

@NTTY Having now sorted out my test rig, I went looking for your latest test CD but all the links I tried are dead?

Where is the latest download?