Technics SL-PG100
This was my first CD player, bought in 1991. It is based on MN66271 1-bit MASH converter. It is incredible but it works flawlessly till nowadays. However, I never liked the sound of the unit and replaced it soon with SONY XA-2ES. Technics was also responsible for my initial dislike of sound of “digital” music. As it is still in my stock and working, I have decided, after decades, to make some measurements on this unit.
THD at 1kHz and 0dBFS
THD is not bad and SINAD (A weighted) is 88dB. Quite acceptable value taking the age of the unit into account. However, noise floor is not clean and shows quite a lot of spectral lines that I call “digital rubbish”. I think this was responsible for unpleasant sound of early digital CD players.
THD at 1kHz and -60dBFS
Again we can see acceptable distortion, but a lot of “rubbish”.
THD at 5kHz and 0dBFS
Distortion is getting worse and we can see mirror images above 22kHz, clear evidence of sub-optimal digital (and analog?) filter section.
THD at 5kHz and -60dBFS
Low distortion however rubbish is present
THD at 50Hz and 0dBFS
Interestingly we can see much higher distortion than at 1kHz. Output electrolytic capacitors?
CCIF IMD 19+20kHz
This is not good. HF linearity is quite poor and we can also see 2 mirror images near Fs/2.
Digital zero
Not so bad and referred to full output noise is about -96dB(A). This measurement was updated on 11/19/2019.
White noise
White noise test shows digital filter behavior and we can see that attenuation above Fs/2 is insufficient. This explains mirror images seen in previous plots.
HF noise spectrum to 10MHz
This is not bad. We can see usual noise shaping of the MASH converter and quite clean spectrum above 1MHz, with some not too high peaks all below -98dBV. However see that there is quite some energy between 100kHz and 1MHz.
Conclusion
The results are not excellent, but not so bad as well. Show me the newer generation CD player which is still functioning after 28 years .
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Follow up (November 21, 2019)
Two measurements are added, DIM (sine 3.18kHz + square 15kHz) and Multitone
DIM measurement, square 3.18kHz + sine 15kHz. Only 4 spectral lines should appear, 3.18 kHz and its 3rd and 5th harmonics and 15kHz
Multitone test. Not bad at all, however IME this test is much easier than DIM.
Updated on November 21, 2019 by pma
This was my first CD player, bought in 1991. It is based on MN66271 1-bit MASH converter. It is incredible but it works flawlessly till nowadays. However, I never liked the sound of the unit and replaced it soon with SONY XA-2ES. Technics was also responsible for my initial dislike of sound of “digital” music. As it is still in my stock and working, I have decided, after decades, to make some measurements on this unit.
THD at 1kHz and 0dBFS
THD is not bad and SINAD (A weighted) is 88dB. Quite acceptable value taking the age of the unit into account. However, noise floor is not clean and shows quite a lot of spectral lines that I call “digital rubbish”. I think this was responsible for unpleasant sound of early digital CD players.
THD at 1kHz and -60dBFS
Again we can see acceptable distortion, but a lot of “rubbish”.
THD at 5kHz and 0dBFS
Distortion is getting worse and we can see mirror images above 22kHz, clear evidence of sub-optimal digital (and analog?) filter section.
THD at 5kHz and -60dBFS
Low distortion however rubbish is present
THD at 50Hz and 0dBFS
Interestingly we can see much higher distortion than at 1kHz. Output electrolytic capacitors?
CCIF IMD 19+20kHz
This is not good. HF linearity is quite poor and we can also see 2 mirror images near Fs/2.
Digital zero
Not so bad and referred to full output noise is about -96dB(A). This measurement was updated on 11/19/2019.
White noise
White noise test shows digital filter behavior and we can see that attenuation above Fs/2 is insufficient. This explains mirror images seen in previous plots.
HF noise spectrum to 10MHz
This is not bad. We can see usual noise shaping of the MASH converter and quite clean spectrum above 1MHz, with some not too high peaks all below -98dBV. However see that there is quite some energy between 100kHz and 1MHz.
Conclusion
The results are not excellent, but not so bad as well. Show me the newer generation CD player which is still functioning after 28 years .
-----------------------------------------------------------------------------------------------------------------------------------------
Follow up (November 21, 2019)
Two measurements are added, DIM (sine 3.18kHz + square 15kHz) and Multitone
DIM measurement, square 3.18kHz + sine 15kHz. Only 4 spectral lines should appear, 3.18 kHz and its 3rd and 5th harmonics and 15kHz
Multitone test. Not bad at all, however IME this test is much easier than DIM.
Updated on November 21, 2019 by pma
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