Hello everyone,
This is a review and detailed measurements of the Revox B 226-S CD stereo player and transport.
This player is a higher level clone of the Revox B 126, which I already reviewed. The main technical difference between the two is the presence of the Philips DAC TDA1541A in the "Crowned" version here (S1).
At the time there were a lot of folks claiming all sorts of extraordinary improvements related to the use of this selected DAC, and since it is implemented here in the same good quality environment, time has come to know the truth, at least on a measurements perspective.
Revox B 226-S - Presentation
This CD player was released in 1991 at nearly twice the price of the B 126, yet featuring the same internals with variable outputs on top. So we find the Philips Oversampling filter SAA7220P/B and the DAC TDA1541A-S1 (instead of the standard TDA1541A in the B 126).
So the main differences are on the outside. Other than the color, there also wooden side panels piano black painted and golden feet... Buttons are golden too on their top edge. The display is fluorescent (blue).
At the back, we get holes, this time, to access the variable outputs since it has the circuitry inside:
Inside, I let you compare with the B 126, for fun:
We have the TDA1541A-S1 with its surrounding decoupling caps, that are different from the B 126, and that could be due to the different production date of these two as I could not find a difference, or recommendation for it, in the service manual.
We see the circuitry for variable outputs, which was empty on the B 126.
The drive is extremely fast to skip one or multiple tracks, similar to the B 126. Scanning a track is little slower than others (again same).
EDIT (20/12/2024): When using the Revox, I noticed some slowness to read the TOC of my test CD and others, so I went for a little refresh:
The intention was not to improve the measurements, but it couldn't do harm and some caps looked tired.
That said, it gained 1dB in noise and distorsion, so I updated couple of measurements without further mention, as it's not of big significance. Other than that, I achieved my initial goal which was to make the drive faster at reading the TOC, and it’s too at skipping a track (I think, not really sure, it could be an impression).
Revox B 226-S - Measurements
From now on, I will be consistent with my measurements as I described them in the post “More than we hear”, and as I reported them for the Onkyo C-733 review. Over time, this will help comparing the devices I reviewed.
The Revox B 226.S outputs 2.10Vrsm, and there was a slight channel imbalance of around 0.13dB, the B 126 did better (0.04dB only). The single-ended outputs are non-inverting.
Here you go with the 999.91Hz sine @0dBFS (without dither) and updated after servicing the unit:
I'll let you compare with the B 126, and this is very close.
THD at -103.7dB, instead of 102.5dB, so that's an equal wow! This is impressive result for the time, one that we don't always find in recent CD players... The two channels have near identical performances, similar to the B 126.
We continue at lower level, that is same 999.91Hz @-6dBFS (without dither):
Again, basically the same performances as the B 126.
Same relatively quiet power supply section too:
Not much leakage from the mains (50Hz in Switzerland).
The below is a new measurement with shaped dither added to the signal and compared to no dither, to see if the DAC has the necessary resolution to benefit from it:
And again, similar to the B 126, nothing to gain from shaping the noise unfortunately, at least at full scale, the conversion generates too much noise, I'd say.
That said, at very low level, noise shaping still helps to have a very decent linearity, here below a tone at -110dBFS which is correctly represented:
It again is the same thing you can see with the B 126 and its non-crowned DAC.
You might have noticed that the pitch error is a little higher with this one (1000.07Hz for 999.91Hz requested and the B 126 was at 1000.02Hz).
Anyways, what you see above means we are way below the strict resolution of the CD Audio. The software calculates a resolution that is near 18bits in this context. Thanks to noise shaping!
Bandwidth (now measured from a long term average of periodic white noise) is nearly flat:
You can see the ringing of the oversampling filter at the upper frequencies. And we also find our 0.13dB channel imbalance (vs 0.04dB with the B 126).
Let's continue with the oversampling filter behavior (from white noise) and together with dual tones 18kHz+20kHz (AES17):
Again, same as what we saw with the B 126 and that is logical because it's the same digital filter, so we find the same attenuation (-50dB minimum) out of band and the same ringing of the filter.
Multitone is also the same as the B 126:
It clears CD Audio data from unwanted distortion and noise.
This is the Jitter test:
On more time, it's nearly identical to that of the B 126, and that is normal for a clone CD Player.
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 Revox B 226.S mean the oversampling filter has roughly 1.5dB 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.
Other measurements (not shown):
And of course, I need to complement this view with a direct comparison between the two bros: B 226-S and B 126:
And voilà, here we see the real difference. The S1 version gets the benefit of improved linearity which shows when the signal goes down. At 1kHz (see the plot), there's almost 2dB less distorsion with the crowned version at -12dBFS.
It's also the same story @-60dBFS. And that's it.
Revox B 226-S - Measurements (Optical Out)
I've seen several of you reviewing CD players using their digital outputs, in case the results could be improved with an external DAC.
First the digital output (coax only) is as what we expect it to be, perfect (999.91Hz @0dBFS without dither):
Similar to the B 126, it was difficult to get a stabilised reading from direct digital feed, and I had to reduce the FFT size to speed the calculation and be able to show an FFT without windowing errors. This is due to pitch error.
Conclusion
As with the B 126, I was positively surprised by this player, especially the first time I read the THD at full scale (wow effect). Of course, as an old R2R not benefitting from laser trimming, it has its limitations, especially at lower levels without dither. The trick of Philips to test low level linearity before stamping those chips below a certain threshold was a nice way to avoid going expensive laser trimming on the production line. In the end, they made it a marketing advantage and it worked. Well done.
Besides the pitch error, I don't see anything to be worried of. We do better today, but it was already crazy good at the time. Noise shaping technique of today saves this DAC at very low levels and since it delivers at high levels, and with a decent resistance to inter-samples over, well... quite modern after all, no?
Now we also get a tangible view at the potential advantages of the "S1" version of the TDA1541A. The improvements are as they were documented by Philips: minimal but tangible.
There’s a lot to like about this player.
I hope you enjoyed the review!
Cheers
PS: I add a link to the nice maintenance guide with many drawings that look to made by hand.
This is a review and detailed measurements of the Revox B 226-S CD stereo player and transport.
This player is a higher level clone of the Revox B 126, which I already reviewed. The main technical difference between the two is the presence of the Philips DAC TDA1541A in the "Crowned" version here (S1).
At the time there were a lot of folks claiming all sorts of extraordinary improvements related to the use of this selected DAC, and since it is implemented here in the same good quality environment, time has come to know the truth, at least on a measurements perspective.
Revox B 226-S - Presentation
This CD player was released in 1991 at nearly twice the price of the B 126, yet featuring the same internals with variable outputs on top. So we find the Philips Oversampling filter SAA7220P/B and the DAC TDA1541A-S1 (instead of the standard TDA1541A in the B 126).
So the main differences are on the outside. Other than the color, there also wooden side panels piano black painted and golden feet... Buttons are golden too on their top edge. The display is fluorescent (blue).
At the back, we get holes, this time, to access the variable outputs since it has the circuitry inside:
Inside, I let you compare with the B 126, for fun:
We have the TDA1541A-S1 with its surrounding decoupling caps, that are different from the B 126, and that could be due to the different production date of these two as I could not find a difference, or recommendation for it, in the service manual.
We see the circuitry for variable outputs, which was empty on the B 126.
The drive is extremely fast to skip one or multiple tracks, similar to the B 126. Scanning a track is little slower than others (again same).
EDIT (20/12/2024): When using the Revox, I noticed some slowness to read the TOC of my test CD and others, so I went for a little refresh:
The intention was not to improve the measurements, but it couldn't do harm and some caps looked tired.
That said, it gained 1dB in noise and distorsion, so I updated couple of measurements without further mention, as it's not of big significance. Other than that, I achieved my initial goal which was to make the drive faster at reading the TOC, and it’s too at skipping a track (I think, not really sure, it could be an impression).
Revox B 226-S - Measurements
From now on, I will be consistent with my measurements as I described them in the post “More than we hear”, and as I reported them for the Onkyo C-733 review. Over time, this will help comparing the devices I reviewed.
The Revox B 226.S outputs 2.10Vrsm, and there was a slight channel imbalance of around 0.13dB, the B 126 did better (0.04dB only). The single-ended outputs are non-inverting.
Here you go with the 999.91Hz sine @0dBFS (without dither) and updated after servicing the unit:
I'll let you compare with the B 126, and this is very close.
THD at -103.7dB, instead of 102.5dB, so that's an equal wow! This is impressive result for the time, one that we don't always find in recent CD players... The two channels have near identical performances, similar to the B 126.
We continue at lower level, that is same 999.91Hz @-6dBFS (without dither):
Again, basically the same performances as the B 126.
Same relatively quiet power supply section too:
Not much leakage from the mains (50Hz in Switzerland).
The below is a new measurement with shaped dither added to the signal and compared to no dither, to see if the DAC has the necessary resolution to benefit from it:
And again, similar to the B 126, nothing to gain from shaping the noise unfortunately, at least at full scale, the conversion generates too much noise, I'd say.
That said, at very low level, noise shaping still helps to have a very decent linearity, here below a tone at -110dBFS which is correctly represented:
It again is the same thing you can see with the B 126 and its non-crowned DAC.
You might have noticed that the pitch error is a little higher with this one (1000.07Hz for 999.91Hz requested and the B 126 was at 1000.02Hz).
Anyways, what you see above means we are way below the strict resolution of the CD Audio. The software calculates a resolution that is near 18bits in this context. Thanks to noise shaping!
Bandwidth (now measured from a long term average of periodic white noise) is nearly flat:
You can see the ringing of the oversampling filter at the upper frequencies. And we also find our 0.13dB channel imbalance (vs 0.04dB with the B 126).
Let's continue with the oversampling filter behavior (from white noise) and together with dual tones 18kHz+20kHz (AES17):
Again, same as what we saw with the B 126 and that is logical because it's the same digital filter, so we find the same attenuation (-50dB minimum) out of band and the same ringing of the filter.
Multitone is also the same as the B 126:
It clears CD Audio data from unwanted distortion and noise.
This is the Jitter test:
On more time, it's nearly identical to that of the B 126, and that is normal for a clone CD Player.
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-25X | -30.2dB | -24.2dB | -27.9dB |
| Yamaha CD-1 (Non-Oversampling CD Player) | -86.4dB | -84.9dB | -78.3dB |
| Onkyo C-733 | -88.3dB | -40.4dB | -21.2dB |
| Denon DCD-900NE | -34.2dB | -27.1dB | -19.1dB |
| Revox B 126 | -60.9dB | -41.3dB | -23.3dB |
| Revox B 226-S | -61.1dB | -41.3dB | -23.3dB |
I kept some references and will keep the same for other reviews, so you can quickly compare. The results of the Revox B 226.S mean the oversampling filter has roughly 1.5dB 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.
Other measurements (not shown):
- IMD AES-17 DFD "Analog" (18kHz & 20kHz 1:1) : -96.7dB
- IMD AES-17 DFD "Digital" (17'987Hz & 19'997Hz 1:1) : -90.0dB
- IMD DIN (250Hz & 8kHz 4:1) : -86.8dB
- Dynamic Range : 97.2dB
- Crosstalk: -116.6dB (1kHz), -99.9dB (10kHz)
- Pitch Error : 20'000.17Hz (19'997Hz requested) ie +0.015% this is worse than the B 126
And of course, I need to complement this view with a direct comparison between the two bros: B 226-S and B 126:
And voilà, here we see the real difference. The S1 version gets the benefit of improved linearity which shows when the signal goes down. At 1kHz (see the plot), there's almost 2dB less distorsion with the crowned version at -12dBFS.
It's also the same story @-60dBFS. And that's it.
Revox B 226-S - Measurements (Optical Out)
I've seen several of you reviewing CD players using their digital outputs, in case the results could be improved with an external DAC.
First the digital output (coax only) is as what we expect it to be, perfect (999.91Hz @0dBFS without dither):
Similar to the B 126, it was difficult to get a stabilised reading from direct digital feed, and I had to reduce the FFT size to speed the calculation and be able to show an FFT without windowing errors. This is due to pitch error.
Conclusion
As with the B 126, I was positively surprised by this player, especially the first time I read the THD at full scale (wow effect). Of course, as an old R2R not benefitting from laser trimming, it has its limitations, especially at lower levels without dither. The trick of Philips to test low level linearity before stamping those chips below a certain threshold was a nice way to avoid going expensive laser trimming on the production line. In the end, they made it a marketing advantage and it worked. Well done.
Besides the pitch error, I don't see anything to be worried of. We do better today, but it was already crazy good at the time. Noise shaping technique of today saves this DAC at very low levels and since it delivers at high levels, and with a decent resistance to inter-samples over, well... quite modern after all, no?
Now we also get a tangible view at the potential advantages of the "S1" version of the TDA1541A. The improvements are as they were documented by Philips: minimal but tangible.
There’s a lot to like about this player.
I hope you enjoyed the review!
Cheers
PS: I add a link to the nice maintenance guide with many drawings that look to made by hand.
Last edited:
