Hello all,
This is a review and measurements of the Unico CDP CD Player from Unison Research (version with one tube). The company is from Italy and I'm not sure if they still exist or not. As with most of the units I get to measure, this came in as defective. The drive was not reading discs.
The unit is rather simple without any extra features. One of the main advertising point of these units was that it had a vacuum tube output buffer. The back of the unit is even simpler and I didn't consider it worth photographing. It has a mains input connector, the analog outputs and a COAX digital output. I was not able to use the later and I'm not sure why. Another "special" feature of these units is that it does not use a "classic" laser unit from Philips, Sony, etc. Instead, it uses a Teac CD-ROM unit with IDE interface. Yes, you read it right. It has a 5.25 inch CD-ROM unit made by Teac (52X if it matters
). This is an older (2002) IDE unit.
The problem with the drive was that it wasn't able to fully load the disc. There was a lot of dust and debris in the mechanical part of the tray and the belt was also worn. After a thorough cleaning and lubing and with the help of a new belt, the drive was loading and readinig the discs pretty nice.
On the inside, it's pretty straight forward:
There is a toroidal transformer for power and the CD-ROM drive is connected to the main board via de IDE ribbon cable. On the main board we see the power supply stage, the DAC IC (CS4392). This is a 24-bit and 192kHz DAC IC that boasts 100dB of THD+N in the datasheet. We can also see the tube buffer made with an ECC82 tube from JJ. Not sure if this is the original one or if it was replaced.
As you cabn see, there was a lot of dust inside and I tried cleaning it as much as possible.
Below you can see the detailed specs of the unit:
General
Technical Data
For the measurements I used @NTTY 's test CD, version 7.2 (again, many thanks) and my Cosmos ADC (gdare A) + Cosmos Scaler.
Here is the 1kHz test tone:
WOW! This is really bad. The second harmonic is through the roof at around -60dB and this dictates the overall performance of THD+N at -57.5dB. We can also see the evidence of high noise as the graph is tiled towards the high frequencies. The two channels were pretty well matched and the output level at 0DBFS was 1.7V. That being said, the third and fourth harmonics are pretty low. There is a debate on the audability of the 2nd harmonic and I can clearly say that I can't hear it at -60dB. I used my headphones and REW and added distorsion over the 1kHz test tone and I was not able to hear when the 2nd harmonic was added. I could clearly hear the 3rd and 4th but not the 2nd. This is just on the test tone. In real life, with a complex signal as music is, there's a high chance that you will hear it. Nevertheless, this is rather poor performance as I was expecting when seeing the tube buffer.
Let's see at -6dB:
We can clearly see the tube at work. With a lower amplitude signal. the 2nd harminic is lower, giving us a slightly better THD+N of -63dB. This is still abismal in my oipinion.
Frequency response looks pretty flat:
Here is the oversampling filter response:
The filter starts attenuating at around 21kHz and at 23.5kHz it hits it's maximum attenuation of around -75dB. Not great if you ask me. We can see rather large ultrasonic artefacts between 30 and 40kHz at around -60dB. We can clearly see the noise shaping happening after 30kHz.
Let's see the multitone:
As expected, this is not great. We have around 75dB of useful range, that is 12.5 bits.
Jitter:
This looks good.
THD vs frequency at -12dB:
Being at a lover level, this is not as bad as the full scale signal, but still pretty bad for a CD player. It's 20dB shy of what it should do.
Now the "intersample-overs" table with the units I measured so far:
I did not perform the measurement for 11025Hz and +3dB as I could see clipping already at -1dB. The graph looks pretty bad when moving from +0.01dB to +1dB (see below):
@+0.01dB
and @ +1.01dB
This tells me that already at +1.01dB it is clipping and it going higher will not give us a diferent result.
Now let's see some IMD graphs:
The performance is poor at around -60dB. I like seeing the IMD graphs but maybe I'll switch to a list like @NTTY is doing in his reviews.
I did not perform any tests on the speed of the drive but I can tell you it's slow. For starters, it take 30s for the unit to warm up as it waits for the tube to get up to temperature. In this time, there's a countdown on the screen and you can't do anything but wait as the buttons do not respond. When going from one track to another it's ok, but when you want to skip several track, it takes a long time as you can't skip several tracks at once by clicking on the buttons, you have to wait for the next track to start and only after this, you can skip to the next one. This might be due to the fact that it uses a computer drive instead of a dedicated drive for audio.
Conclusion:
Well the measurements speak for themselvs. This is not a well pwerfoming device and I can't see any reasons why you would buy one, considering the price of around 1000EUR. There are many new options that perform far better. It doesn't sound bad as I can't really hear the 2nd harmonic but we can't deny what the measurements show. For some reason I was not able to test the digital output of the unit. I suspect it's a far better option to use an external DAC in order to avoid using the internal one. The internal DAC itself is not bad, but the analog stage containing a valve is not doing a good enough job.
I hope this review helps you if you were lookinmg at the uinit second-hand.
All the best,
Horia
This is a review and measurements of the Unico CDP CD Player from Unison Research (version with one tube). The company is from Italy and I'm not sure if they still exist or not. As with most of the units I get to measure, this came in as defective. The drive was not reading discs.
The unit is rather simple without any extra features. One of the main advertising point of these units was that it had a vacuum tube output buffer. The back of the unit is even simpler and I didn't consider it worth photographing. It has a mains input connector, the analog outputs and a COAX digital output. I was not able to use the later and I'm not sure why. Another "special" feature of these units is that it does not use a "classic" laser unit from Philips, Sony, etc. Instead, it uses a Teac CD-ROM unit with IDE interface. Yes, you read it right. It has a 5.25 inch CD-ROM unit made by Teac (52X if it matters
). This is an older (2002) IDE unit.The problem with the drive was that it wasn't able to fully load the disc. There was a lot of dust and debris in the mechanical part of the tray and the belt was also worn. After a thorough cleaning and lubing and with the help of a new belt, the drive was loading and readinig the discs pretty nice.
On the inside, it's pretty straight forward:
There is a toroidal transformer for power and the CD-ROM drive is connected to the main board via de IDE ribbon cable. On the main board we see the power supply stage, the DAC IC (CS4392). This is a 24-bit and 192kHz DAC IC that boasts 100dB of THD+N in the datasheet. We can also see the tube buffer made with an ECC82 tube from JJ. Not sure if this is the original one or if it was replaced.
As you cabn see, there was a lot of dust inside and I tried cleaning it as much as possible.
Below you can see the detailed specs of the unit:
General
- Manufacturer: Unison Research
- Model: Unico CDP
- Years of manufacture:
- Made in: Italy
- Color: black, silver
- Remote control: yes
- Dimensions: 435 x 95 x 340 mm (WxHxD)
- Weight: 10 kg
- Original price approx.: 1300,- - 1400,- €
Technical Data
- Output tube: 1 X ECC 83 (Class A triode tube output stage)
- D/A converter: 1 x Crystal CS 4392, stereo converter
- oversampling rate: Crystal CS 8420 24 bit / 96 Khz
- Output impedance: < 100 Ohm
- Display: Toshiba LCD graphic text display. 128x64 pixel resolution
- Remote control: System remote control made of plastic, wooden remote control optional
- Drive: Highly selected Teac CD Rom drive
For the measurements I used @NTTY 's test CD, version 7.2 (again, many thanks) and my Cosmos ADC (gdare A) + Cosmos Scaler.
Here is the 1kHz test tone:
WOW! This is really bad
. The second harmonic is through the roof at around -60dB and this dictates the overall performance of THD+N at -57.5dB. We can also see the evidence of high noise as the graph is tiled towards the high frequencies. The two channels were pretty well matched and the output level at 0DBFS was 1.7V. That being said, the third and fourth harmonics are pretty low. There is a debate on the audability of the 2nd harmonic and I can clearly say that I can't hear it at -60dB. I used my headphones and REW and added distorsion over the 1kHz test tone and I was not able to hear when the 2nd harmonic was added. I could clearly hear the 3rd and 4th but not the 2nd. This is just on the test tone. In real life, with a complex signal as music is, there's a high chance that you will hear it. Nevertheless, this is rather poor performance as I was expecting when seeing the tube buffer.Let's see at -6dB:
We can clearly see the tube at work. With a lower amplitude signal. the 2nd harminic is lower, giving us a slightly better THD+N of -63dB. This is still abismal in my oipinion.
Frequency response looks pretty flat:
Here is the oversampling filter response:
The filter starts attenuating at around 21kHz and at 23.5kHz it hits it's maximum attenuation of around -75dB. Not great if you ask me. We can see rather large ultrasonic artefacts between 30 and 40kHz at around -60dB. We can clearly see the noise shaping happening after 30kHz.
Let's see the multitone:
As expected, this is not great. We have around 75dB of useful range, that is 12.5 bits.
Jitter:
This looks good.
THD vs frequency at -12dB:
Being at a lover level, this is not as bad as the full scale signal, but still pretty bad for a CD player. It's 20dB shy of what it should do.
Now the "intersample-overs" table with the units I measured so far:
CD player | 5512.5 Hz sine, Peak = +0.69dBFS | 7350 Hz sine, Peak = +1.25dBFS | 11025 Hz sine, Peak = +3.0dBFS |
| Marantz CD52mk2 - SE | -34dB | -27.6dB | -16.2dB |
| Marantz CD67mk2 | -37.6dB | -29.1dB | -19.3dB |
| Marantz SA-14 | -47dB | -32.6dB | -21.4dB |
| Unison Reserach UNICO CDP (single valve) | -34.6dB | -27dB | -29.6dB (only at -1.01dB) - H3 dominated |
I did not perform the measurement for 11025Hz and +3dB as I could see clipping already at -1dB. The graph looks pretty bad when moving from +0.01dB to +1dB (see below):
@+0.01dB
and @ +1.01dB
This tells me that already at +1.01dB it is clipping and it going higher will not give us a diferent result.
Now let's see some IMD graphs:
The performance is poor at around -60dB. I like seeing the IMD graphs but maybe I'll switch to a list like @NTTY is doing in his reviews.
I did not perform any tests on the speed of the drive but I can tell you it's slow. For starters, it take 30s for the unit to warm up as it waits for the tube to get up to temperature. In this time, there's a countdown on the screen and you can't do anything but wait as the buttons do not respond. When going from one track to another it's ok, but when you want to skip several track, it takes a long time as you can't skip several tracks at once by clicking on the buttons, you have to wait for the next track to start and only after this, you can skip to the next one. This might be due to the fact that it uses a computer drive instead of a dedicated drive for audio.
Conclusion:
Well the measurements speak for themselvs. This is not a well pwerfoming device and I can't see any reasons why you would buy one, considering the price of around 1000EUR. There are many new options that perform far better. It doesn't sound bad as I can't really hear the 2nd harmonic but we can't deny what the measurements show. For some reason I was not able to test the digital output of the unit. I suspect it's a far better option to use an external DAC in order to avoid using the internal one. The internal DAC itself is not bad, but the analog stage containing a valve is not doing a good enough job.
I hope this review helps you if you were lookinmg at the uinit second-hand.
All the best,
Horia
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