Measurements of the Marantz CD52-Mk2 Special Edition cd player

[horias2000]

After reading @NTTY 's review of the Dedon DCD SA-1 cd player, I was curious how my old CD players would perform. With the test CD made by @NTTY and with some help from him (thanks for that) I was able to measure both my CD players. This post is for the CD52-Mk2 Special edition and another post will follow for the CD67 Mk2.
The CD52-Mk2 Special Edition was released in early 90s and it featured a cast-iron swing-arm CD transport (CDM 4/19) made by Philips and it was (to my knowledge) the first bit-stream implementation by Philips, using the SAA7350 DAC chip. I bought this player a few years ago as I was curious how it sounded. Overall, I like the sound, it's clean and I can't really hear any distortion or any other sorts of artifacts.

Here are some pics of the device:

I think that the "Special Edition" treatment is found on the transformer that is covered in some sort of resin and the reinforcement of the enclosure. Everything is made out of glorious 90s plastic and the display is the blue neon type (fitting for the 90s).

Overall, I think internals look pretty well made and using SMD's for that day and age is pretty awesome. The DC67 uses only THT components.

The measurement setup is made out of the Cosmos ADC set to the 1.7Vrms input range (lowest) in MONO mode and REW. The thing with the Cosmos ADC is that I can' set the actual gain to 0dBFS as it has the internal input attenuator and I do not know how to compensate for this. I can add a preamp at the input but this will have an effect on the absolute performance of the device. So you will see that most of the measurements have an attenuation of -8dB.

Now onto some measurements.

As I said, I used the test CD made by @NTTY.

First is the 1kHz, 0dBFS:

This looks pretty good to me. A THD+N measurement of about -88dB is really good for such an old device. The ENOB measurement (16.2 bits) is not correct due to the gain issue I described above. It is around 14.6 bits. Again, not too bad in my opinion.

Next I looked at the multi tone:

This shows almost 100dB of range and this is pretty good again.

Next, the J-test

There is some random noise but it's below -90dB and it should not be audible, at least not to my ears.

Next I had a look at the frequency response:

It start attenuating at around 21kHz and max attenuation is around -90dB. I used the measurement from the CD67 as I realized that the one for the CD52 was not correct. Both measurements were identical in terms of frequency response. When I get the chance, I will update the post with the actual FR of the CD52 Mk3 SE.

Next I looked at the transport performance by using a D50s external DAC and feeding the digital output via a COAX cable. This player only has the option of COAX digital output. Here are the results:

As it can be seen from the measurements above, the performance increases considerably and it is clear that as a transport, this is pretty good. I mostly use it as a transport feeding into my SMSL SU9-n DAC.

Overall I have to say that I'm pleased with the performance of the CD52 Mk2 - SE as a device. Its DAC performance is decent and the transport is pretty good. I'm using it mostly with an external DAC anyways but I listen using the internal DAC from time to time.

Stay tuned for the CD67 Mk2 (no Special Edition)...

 

[staticV3]

First is the 1kHz, 0dBFS:

-8.22dBFS into the Cosmos ADC set to 1.7V would mean a rather low output voltage of 0.7Vrms from the CD52-Mk3.

That's pretty surprising since the CD players measured by NTTY all output about 1.9-2.1V

Have you tried double-checking the output voltage with a multimeter?

 

[horias2000]

-8.22dBFS into the Cosmos ADC set to 1.7V would mean a rather low output voltage of 0.7Vrms from the CD52-Mk3.

That's pretty surprising since the CD players measured by NTTY all output about 1.9-2.1V

Have you tried double-checking the output voltage with a multimeter?

Indeed, looking the the 1kHz output with the scope tool in REW, I get around 1.4Vpk-pk. This is around 1Vrms. I think that the standard for CD players in the past was 1Vrms output. I might be wrong but I clearly remember reading this in one of Douglas Self's books. I will try to measure the output with a multimeter and a 50Hz fundamental.

 

[staticV3]

Indeed, looking the the 1kHz output with the scope tool in REW, I get around 1.4Vpk-pk. This is around 1Vrms.

1.4Vpp = 0.5Vrms

Are you sure that you've properly calibrated REW before using the scope tool?

I will try to measure the output with a multimeter and a 50Hz fundamental.

Many multimeters are flat to ~1-2kHz actually, in which case you could use the same 1kHz CD that you've used above.

For example, here's my Aneng AN870:


Measuring your DMM's response once, can save you time down the line

 

[restorer-john]

Indeed, looking the the 1kHz output with the scope tool in REW, I get around 1.4Vpk-pk. This is around 1Vrms. I think that the standard for CD players in the past was 1Vrms output. I might be wrong but I clearly remember reading this in one of Douglas Self's books. I will try to measure the output with a multimeter and a 50Hz fundamental.

CD "standard" was 2.0V RMS from the introduction of the format in March 1983. Prior to that, it was to be 1.4V RMS.

The output impedance of the CD-52mk2 is approximately 200R.

So, with the Cosmos ADC presenting a rated input impedance of 640R on the 1.7V range, your ~2.0V RMS is driving a total of 840R, with 200R of that in the player itself. The NE5532 can drive 600R loads, but you are losing nearly 24% in the player's resistors. Basically, you need a low distortion buffer between your source (CD player, whatever) to present essentially no load of significance to the source, otherwise your THD, output levels and even noise figures will be totally wrong. Proper analysers have a 100-200k Ohm input impedance so they are not loading down and distorting the source. The Cosmos is fine for amplifiers, but not for high impedance (relatively) sources- it needs a buffer.

 

[horias2000]

My bad. I just measured the output when it was playing a 100Hz 0dBFS tone. The output is 2.3Vrms

 

[horias2000]

CD "standard" was 2.0V RMS from the introduction of the format in March 1983. Prior to that, it was to be 1.4V RMS.

The output impedance of the CD-52mk2 is approximately 200R.

View attachment 394017

So, with the Cosmos ADC presenting a rated input impedance of 640R on the 1.7V range, your ~2.0V RMS is driving a total of 840R, with 200R of that in the player itself. The NE5532 can drive 600R loads, but you are losing nearly 24% in the player's resistors. Basically, you need a low distortion buffer between your source (CD player, whatever) to present essentially no load of significance to the source, otherwise your THD, output levels and even noise figures will be totally wrong. Proper analysers have a 100-200k Ohm input impedance so they are not loading down and distorting the source. The Cosmos is fine for amplifiers, but not for high impedance (realtively) sources- it needs a buffer.

I was thinking of making a high impedance, variable gain stage using something like the OPA1612. This should be good enough for the input of the Cosmos.

 

[staticV3]

I was thinking of making a high impedance, variable gain stage using something like the OPA1612. This should be good enough for the input of the Cosmos.

If you want something premade, the Cosmos Scaler is an ideal buffer+autoranging preamp for the ADC.

If you just need the buffer, all Cosmos ADC boards come with unpopulated solder pads to add an Op-amp buffer stage.

 

[horias2000]

If you want something premade, the Cosmos Scaler is an ideal buffer+autoranging preamp for the ADC.

Yes, the Scaler is also a very good option. It uses the OPA1612 as well but it might be cheaper than me making the PCBs and finding an enclosure.

 

[restorer-john]

I just measured the output when it was playing a 100Hz 0dBFS tone. The output is 2.3Vrms

Love that Keysight 34461A. Nice piece of gear.

 

[horias2000]

Love that Keysight 34461A. Nice piece of gear.

Yes, I agree. It's a really nice tool. I have one in the lab where I work and I found a really good deal a few years ago and I didn't hesitate. Really good DMM.

 

[GXAlan]

The Cosmos is fine for amplifiers, but not for high impedance (relatively) sources- it needs a buffer.

The alternative is to use the 10V or even the 43V input. Even though your noise is higher and you don’t see the 120+ dB SNR, the impedance is better .

 

[horias2000]

I ordered the Cosmos Scaler. I will measure again when it arrives.

 

[AnalogSteph]

Measuring in mono mode with one output split into two inputs could explain why there was such substantial attenuation - that would halve ADC input impedance to 320 ohms, bringing input level down to about 1.4 Vrms. If the output opamp wasn't a 5532 but one of the lesser parts of the day (say a 4565), you would have seen a fair bit more distortion. This part can drive like 6-8 Vrms into 600 ohms without breaking much of a sweat, so 2 Vrms into 520 ohms isn't a major challenge. I still have a little headphone amp using one floating around.

In the meantime, as suggested just use the 8.5 Vrms or 10 Vrms range and only one input channel in stereo mode. A 5532 should be driving 2 V into 3.12 / 3.48 kOhms with ease, and you should still have plenty of ADC dynamic range for a measly CD player even when leaving ~12 dB of headroom. Even the 1.66 kOhms of the 4.5 Vrms range should not stress it very much, NwAvGuy got over 7 Vrms into ~1.3 kOhms out of it at <-100 dB THD at a gain of 7.

So yes, the output stage actually is substantially overbuilt for the job. And that's not nearly the end of it - in some TOTL models I've seen constructions that would make a dedicated headphone amp proud, with discrete medium power transistors and all.

 

[restorer-john]

in some TOTL models I've seen constructions that would make a dedicated headphone amp proud, with discrete medium power transistors and all.

This springs to mind as such an example...

Sony CDP-X777es.

And this is the headphone stage and variable line out stage too.

Overkill if ever I saw it.