Panasonic SL-NP40 MASH Portable CD Player Measurements

[tpd]

Promised long ago, I'm finally posting measurements for what I thought might be an interesting CD player from a previous era: a 1994 Panasonic SL-NP40 portable featuring XBS and MASH digital processing.

I tested via line out with no high filter or XBS, and with both AC (via what appears to be the original wall wart) and battery power.

The details of this player are lost to time, but let's see what we have.

Does that take you back to a simpler time? Do you still have a cassette adapter stashed away in a drawer somewhere? Let's see how this measures...

Note that the source file here is the 999.91Hz no dither test track from Flo's test CD. I'm assuming the measured 1002.19Hz tone represents a non-trivial pitch error in playback. That is consistent throughout my tests of this player (I tested three times altogether) and the largest pitch difference of any CD player I've tested so far.

(Updated measurement here retaken with correct settings.)

And finally, here's the 999Hz -6dBFS measurement comparing AC (green) and battery (red) powered playback. Right channel only. It's odd that we see the 60Hz spike even when on battery power (AC completely unplugged from the unit).

Measuring AC versus battery: after some further research and experimentation, it's clear that my plugged in laptop was impacting the test results, injecting some 60Hz noise. I retested on battery power and those updated measurements are included below.

Overall, not great. There's definitely a tradeoff for convenience of a portable player, and I'm not sure this is the best showcase for the MASH processor.

Thanks for your patience. Cheers.

Added note: test setup is NTTY's Test CD 7.2 > DUT > Focusrite Scarlett 2i2 Gen 3 > MacBook Pro M2 Pro

 

[NTTY]

Interesting, thanks for sharing.

There’s roughly 10dB too much random noise, and a bit high distorsion, but it’s still ok. Rest of measurements are decent. I’m surprised of the elevated noise floor for the Multitone Test. What FFT window did you use for this one?

Pitch error is a massive 2300ppm but I guess even that is hard to spot when listening to music, right?

 

[antcollinet]

It's odd that we see the 60Hz spike even when on battery power (AC completely unplugged from the unit).

That must be coming in from your test setup somewhere. Obviously it's not coming from the battery.

Interesting test though. I have no doubt that under the normal listening conditions these things were typically used (out and about with crappy earbuds) - the defects are inaudible. In fact it near as damnit meets my personal "won't go lower" target of 80dB THD+N, and multitone noise floor for any purpose.

 

[Mart68]

Aside from the pitch error and the early HF roll off it seems to clear the 'good enough' bar.

 

[antcollinet]

Pitch error is a massive 2300ppm but I guess even that is hard to spot when listening to music, right?

Aside from the pitch error and the early HF roll off it seems to clear the 'good enough' bar.

0.23% fixed error - no I don't think anyone can detect that with music, without a reference to ab against. Even with a reference I'd not be surprised if people were unable to hear a difference.

 

[necronaut]

I notice noise at around 60Hz.

Are you powering this with a mains power supply? Could there be a difference when powered by batteries?

 

[tpd]

Interesting, thanks for sharing.

There’s roughly 10dB too much random noise, and a bit high distorsion, but it’s still ok. Rest of measurements are decent. I’m surprised of the elevated noise floor for the Multitone Test. What FFT window did you use for this one?

Pitch error is a massive 2300ppm but I guess even that is hard to spot when listening to music, right?

FFT window was 512k as suggested.

 

[tpd]

I notice noise at around 60Hz.

Are you powering this with a mains power supply? Could there be a difference when powered by batteries?

I measured with both AC and batteries. Same result.

Could it be part of my test setup? Perhaps, but this 15-20dB higher than what I see with other players I've tested. I will do some other tests to see whether my gear is impacting the results.

 

[NTTY]

FFT window was 512k as suggested.

I guess the sampling rate of the input interface way 192kHz. Best in class is the below:

Yours is 30dB higher noise floor but that does not correlate with the other measurements. It was Blackman-Harris 7 window, right?

 

[tpd]

Ah, I had the sampling frequency set incorrectly. I will re-measure. Here's a previous test that I measured using the correct settings, I think.

 

[lini]

(...) The details of this player are lost to time, but let's see what we have. (...)

Looks to me like that SL-NP40 would be a Panasonic-labelled model variant of the Technics SL-XP160/165/170/180/250(C) family.

Greetings from Munich!

Manfred / lini

 

[AnalogSteph]

Note that the source file here is the 999.91Hz no dither test track from Flo's test CD. I'm assuming the measured 1002.19Hz tone represents a non-trivial pitch error in playback. That is consistent throughout my tests of this player (I tested three times altogether) and the largest pitch difference of any CD player I've tested so far.

PLL clockgen. Same magnitude as Clip+ pitch error:

Sansa Clip+ Measured

INTRO - DOES THE CLIP+ DESERVE ALL THE PRAISE? (revised 2/23/11) The Sansa Clip+ is a seriously popular player with over 1500 people on Am...

nwavguy.blogspot.com

From memory, the proper fix in that case involved roping in a second PLL what had previously sat dormant. Then the reference frequency for the DAC clock could be chosen more favorably instead of being a compromise.

 

[tpd]

Digging further, it looks like my laptop on AC power is impacting the test results. I re-measured on battery -- both laptop and the cd player. 60Hz spike is gone.

Here we compare the old AC-powered measurements with a new all-battery measurements.

And a revised multitone measurement on battery, using the correct test settings. (I updated this one in the original post as well.)

 

[USER]

For whatever it's worth these are my measurements of the Panasonic SL-S140. Essentially same SINAD and FR. I'd bet they are pretty much the same thing.

I used PMA's 1kHz sine test CD, Line Out, Vol 5 (0.69V), Battery Power -> E1DA Cosmos -> Laptop

Some RightMark numbers

 

[antcollinet]

Digging further, it looks like my laptop on AC power is impacting the test results. I re-measured on battery -- both laptop and the cd player. 60Hz spike is gone.

What is the updated THD+N on all battery?

 

[tpd]

What is the updated THD+N on all battery?

 

[antcollinet]

View attachment 489888

View attachment 489889

So basically unchanged - dominated by the harmonic distortion.

 

[Orion76]

Very interesting, thanks!

Remember when Stereophile went nuts for the $130 Radio Shack Optimus CD-3400 portable CD player back in the mid 90s? All the classic audiophile stuff is there- more air, breathtaking soundstage, palpable sense of space, congested dynamics, Harmonix feet, a Shun Mook Mpingo disc...

Someone even made and sold a fancy $300 power supply for it!

Than along came the measurements here.

 

[SMc]

Very interesting, thanks!

Remember when Stereophile went nuts for the $130 Radio Shack Optimus CD-3400 portable CD player back in the mid 90s? All the classic audiophile stuff is there- more air, breathtaking soundstage, palpable sense of space, congested dynamics, Harmonix feet, a Shun Mook Mpingo disc...

Someone even made and sold a fancy $300 power supply for it!

Than along came the measurements here.

When my car cd player stopped working I was surprised to find my 3400 still works! Seeing the measurements is a nice confirmation of my chosen car eq setting: a mild bass boost and a severe treble cut.

 

[joostdh]

Looks to me like that SL-NP40 would be a Panasonic-labelled model variant of the Technics SL-XP160/165/170/180/250(C) family.

Indeed. I had a Technics that is exactly like the here tested Panasonic.

typically used (out and about with crappy earbuds)

I shudder to think how the earbuds I used back then measured. Certainly a much weaker link than a portable cd player like this.