This is a review and detailed measurements of the Onkyo C-733 CD stereo player and transport.
This is my first for me on your site, so I'm bit stressed
and please accept my apologies in advance for any mistakes. And of course, as I'm eager to learn and improve, so feel free to ask and/or challenge what I published.
Before starting, please note that I'm not using an AP but REW software with a Motu Ultralite MK5 pro interface. This setup has its limitations, but to test a pure CD Player, it's good enough.
Over the last two years of experiencing CD Players measurements, I came to make myself a Test CD, after having tested those of Denon and Sony. I've already talked about the 44 tracks of that CD here. If you'd like to receive a copy and/or the excel file with the description of the tests and how I run them in REW, please pm me.
One important note: since the input gain of my measurement interface (Motu) can only be adjusted by steps of 1dB, and because not all CD players output a precise exact 2Vrms output, I had to set a convention for my tests, which is
The reason for this review is mainly after I read the review of the Cayin Mini-CD MKII. Since I'm used to test old CD Players, I wanted to perform measurements of an older Japanese mini CD Player.
Onkyo C-733 - Presentation
This CD player is from 2005 and was part of the top line of mini components from Onkyo. It was available as part of the PHA-933 combo including an integrated amplifier, a tuner and this CD player.
The C-733 features a 24bits/192kHz converter from Cirrus Logic (CS4396-KS). Back panel shows two optical digital outputs (to compare DACs) and RCA connectors. That's all, no phones out.
Inside, all electronic cards are labelled Onkyo and well arranged, as far as I can tell. Output stage uses the infamous NE5532. I'll add some pictures later on if you're interested.
I got it for 120$ or so, and that was including the amplifier and tuner from the same combo (PHA-933).
Onkyo C-733 - Measurements (Analog out)
The Onkyo C-733 outputs exactly the standard 2Vrsm..
Here you go with the standard 1kHz sine @0dBFS (dithered) from my test CD (RCA out):
Right and left channels are shown and are identical, it's not so often. THD sits at -100dB and so will clear CD Audio content.
SINAD and ENOB are limited by the dithered noise of the test CD, but could be almost 2dB better, as what we'll see later from the digital output.
You probably already noticed that this is a very quiet CD player, with minimum power supply–related spuriae in its output (below -120dB at 50Hz) :
Bandwidth is nearly flat (-0.8dB @20kHz) and the two channels are matching at 0.05dB (very good) :
The roll off at 20kHz is due to the oversampling filter, and this is below of view of its behavior (from white noise) and together with dual tones 18kHz+20kHz (AES17) :
As you can see, the out of band attenuation is 90dB, which is decent. Artifacts of the conversion (aliases) are therefore well reduced. No sign of massive Noise Shaping either, at least up to 48kHz.
From the above, you can also see that the IMD is quite low (-92.3dB).
Multitone (1/20 decade) shows a happy CD player, not having issue to clear 16bits of data:
The player does not add jitter, as per the below view:
This is an overlay of Analog (bleu) and Digital outputs (red). The Onkyo C-733 does not add jitter on top of what's potentially on the Test CD. Note only very low level additional rays of no concerns.
Started with the Teac VRDS-20 review, and on your request + support to get it done (more here), I'm adding now an "intersample-overs" test which intends to identify the behavior of the digital filtering and DAC when it come to process near clipping signals. Because of the oversampling, there might be interpolated data that go above 0dBFS and would saturate (clip) the DAC and therefore the output. And this effect shows through distorsion (THD+N measurement up to 96kHz):
I kept some references and will keep the same for other reviews, so you can quickly compare. The results of the Onkyo C-733 mean the oversampling filter has roughly 1dB headroom, which is good because it will prevent intersample-overs and therefore clipping where it's most likely to happen. The Yamaha CD-1 shines here because it's old enough not to have an oversampling filter.
Onkyo C-733 Measurements - Optical Out
I've seen several of you reviewing CD players using their digital outputs, in case the results could be improved from an external DAC.
First the digital output (optical only) is as what we expect it to be, perfect :
Distortion is buried in the dither noise and therefore non existent. By the way, about the digital output quality, I already suggested here the use of an undithered 1kHz sine at -90.31dBFS to verify the quality of the drive, should we have doubts. With 16bits, the signal should appear (on a scope) as the 3DC levels of the sign magnitude smallest digital signal, which is what we get with the Onkyo :
The ringing is due to Gibbs Phenomenon.
Since we are on this view, let's quickly come back to the analog output of the same. Stereophile was often using the measurement as a prof of low noise DAC. Let's see if our smallest signal can be recognized from the analog outputs:
Not so bad, I must say, and in par with several much more high end players.
Last but not least, and to mix again Analog and Digital outputs, I like to have a look a the THD vs Frequency when using a -12dBFS signal. This has proven to me to be a key differentiator, especially when I'm measuring an old CD Player using R2R conversion. Here are the results with the Onkyo (Left and Right analog Channels shown, with one digital channel) :
It is the best measurement I've seen (of this one), equal to the best CD Players I own. The red trace is the digital out. This view restricts the measurement to THD over 5 harmonics only. What we see is that the DAC of this player adds only 2dB of distortion at 1kHz (plot), and more at low level, but of no consequences. I am impressed simply because I've never seen better and often (much) worse.
Conclusions
The Analog output of this player is close to what's digitally recorded on my test CD. If we can probably find a better external DAC, there's obviously little more to expect.
Well done to Onkyo, and for those of you still enjoying spinning a CDA, you have more than a competent player here, which you can also use as a transport.
I hope you enjoyed the review, and again let me know how to improve and if you have questions. I have recorded all the 44 measurements and if you want me to publish others or run one of your choice, feel free to ask.
Thank you.
————
Flo
This is my first for me on your site, so I'm bit stressed
and please accept my apologies in advance for any mistakes. And of course, as I'm eager to learn and improve, so feel free to ask and/or challenge what I published.Before starting, please note that I'm not using an AP but REW software with a Motu Ultralite MK5 pro interface. This setup has its limitations, but to test a pure CD Player, it's good enough.
Over the last two years of experiencing CD Players measurements, I came to make myself a Test CD, after having tested those of Denon and Sony. I've already talked about the 44 tracks of that CD here. If you'd like to receive a copy and/or the excel file with the description of the tests and how I run them in REW, please pm me.
One important note: since the input gain of my measurement interface (Motu) can only be adjusted by steps of 1dB, and because not all CD players output a precise exact 2Vrms output, I had to set a convention for my tests, which is
- If the 0dBFS output of the CD player matches the input of the Motu no higher than -0.6dBFS, then I don’t adjust the input gain of the Motu.
- From -0.59dBFS up to 0dBFS, I reduce the input gain by 1dB to prevent clipping the Motu ADC.
The reason for this review is mainly after I read the review of the Cayin Mini-CD MKII. Since I'm used to test old CD Players, I wanted to perform measurements of an older Japanese mini CD Player.
Onkyo C-733 - Presentation
This CD player is from 2005 and was part of the top line of mini components from Onkyo. It was available as part of the PHA-933 combo including an integrated amplifier, a tuner and this CD player.
The C-733 features a 24bits/192kHz converter from Cirrus Logic (CS4396-KS). Back panel shows two optical digital outputs (to compare DACs
) and RCA connectors. That's all, no phones out.Inside, all electronic cards are labelled Onkyo and well arranged, as far as I can tell. Output stage uses the infamous NE5532. I'll add some pictures later on if you're interested.
I got it for 120$ or so, and that was including the amplifier and tuner from the same combo (PHA-933).
Onkyo C-733 - Measurements (Analog out)
The Onkyo C-733 outputs exactly the standard 2Vrsm..
Here you go with the standard 1kHz sine @0dBFS (dithered) from my test CD (RCA out):
Right and left channels are shown and are identical, it's not so often. THD sits at -100dB and so will clear CD Audio content.
SINAD and ENOB are limited by the dithered noise of the test CD, but could be almost 2dB better, as what we'll see later from the digital output.
You probably already noticed that this is a very quiet CD player, with minimum power supply–related spuriae in its output (below -120dB at 50Hz) :
Bandwidth is nearly flat (-0.8dB @20kHz) and the two channels are matching at 0.05dB (very good) :
The roll off at 20kHz is due to the oversampling filter, and this is below of view of its behavior (from white noise) and together with dual tones 18kHz+20kHz (AES17) :
As you can see, the out of band attenuation is 90dB, which is decent. Artifacts of the conversion (aliases) are therefore well reduced. No sign of massive Noise Shaping either, at least up to 48kHz.
From the above, you can also see that the IMD is quite low (-92.3dB).
Multitone (1/20 decade) shows a happy CD player, not having issue to clear 16bits of data:
The player does not add jitter, as per the below view:
This is an overlay of Analog (bleu) and Digital outputs (red). The Onkyo C-733 does not add jitter on top of what's potentially on the Test CD. Note only very low level additional rays of no concerns.
Started with the Teac VRDS-20 review, and on your request + support to get it done (more here), I'm adding now an "intersample-overs" test which intends to identify the behavior of the digital filtering and DAC when it come to process near clipping signals. Because of the oversampling, there might be interpolated data that go above 0dBFS and would saturate (clip) the DAC and therefore the output. And this effect shows through distorsion (THD+N measurement up to 96kHz):
| Intersample-overs tests Bandwidth of the THD+N measurements is 20Hz - 96kHz | 5512.5 Hz sine, Peak = +0.69dBFS | 7350 Hz sine, Peak = +1.25dBFS | 11025 Hz sine, Peak = +3.0dBFS |
| Teac VRDS-20 | -30.7dB | -26.6dB | -17.6dB |
| Yamaha CD-1 (Non-Oversampling CD Player) | -79.6dB | -35.3dB | -78.1dB |
| Onkyo C-733 | -79.8dB | -29.4dB | -21.2dB |
| Denon DCD-900NE | -34.2dB | -30.4dB | -19.1dB |
I kept some references and will keep the same for other reviews, so you can quickly compare. The results of the Onkyo C-733 mean the oversampling filter has roughly 1dB headroom, which is good because it will prevent intersample-overs and therefore clipping where it's most likely to happen. The Yamaha CD-1 shines here because it's old enough not to have an oversampling filter.
Onkyo C-733 Measurements - Optical Out
I've seen several of you reviewing CD players using their digital outputs, in case the results could be improved from an external DAC.
First the digital output (optical only) is as what we expect it to be, perfect :
Distortion is buried in the dither noise and therefore non existent. By the way, about the digital output quality, I already suggested here the use of an undithered 1kHz sine at -90.31dBFS to verify the quality of the drive, should we have doubts. With 16bits, the signal should appear (on a scope) as the 3DC levels of the sign magnitude smallest digital signal, which is what we get with the Onkyo :
The ringing is due to Gibbs Phenomenon.
Since we are on this view, let's quickly come back to the analog output of the same. Stereophile was often using the measurement as a prof of low noise DAC. Let's see if our smallest signal can be recognized from the analog outputs:
Not so bad, I must say, and in par with several much more high end players.
Last but not least, and to mix again Analog and Digital outputs, I like to have a look a the THD vs Frequency when using a -12dBFS signal. This has proven to me to be a key differentiator, especially when I'm measuring an old CD Player using R2R conversion. Here are the results with the Onkyo (Left and Right analog Channels shown, with one digital channel) :
It is the best measurement I've seen (of this one), equal to the best CD Players I own. The red trace is the digital out. This view restricts the measurement to THD over 5 harmonics only. What we see is that the DAC of this player adds only 2dB of distortion at 1kHz (plot), and more at low level, but of no consequences. I am impressed simply because I've never seen better and often (much) worse.
Conclusions
The Analog output of this player is close to what's digitally recorded on my test CD. If we can probably find a better external DAC, there's obviously little more to expect.
Well done to Onkyo, and for those of you still enjoying spinning a CDA, you have more than a competent player here, which you can also use as a transport.
I hope you enjoyed the review, and again let me know how to improve and if you have questions. I have recorded all the 44 measurements and if you want me to publish others or run one of your choice, feel free to ask.
Thank you.
————
Flo
Last edited:
