This is a review, detailed measurements, and listening tests of Innuos PhoenixUSB Reclocker. It is on kind loan from a member and costs US $4,349 (not a typo).
The front panel is quite attractive and gives the impression of a high-end product. Alas, I would have expected to see an indicator that the unit is on, and another that would say it is doing something useful (clocking). The back panel is sparse as well:
Not happy about the stamped sheet metal enclosure and crooked safety sticker. And what is there to read in the manual? It is just a couple of pages and says to connect the source to the USB In and the DAC to USB Out. Pretty sure if you don't know this, you need to get out of computer audio.
If you don't know what this box does, here are the statements from the company:
Innuos applied 3 main design approaches learning from their experience with the Innuos flagship music server, the STATEMENT:
01.
The USB chip regenerating the signal contains no switching regulators. All 3 independent voltages to the chip originate from an independent linear power supply with further regulation provided by 3 sets of LT3045 regulators.
02.
The use of a 3ppb OCXO clock running directly at 24MHz and connected via a board track just a couple of inches away from the USB chip. Therefore, no precision is lost within cables and connectors, as is the case when using an external master 10MHz clock with an additional 24MHz clock generator.
03.
Two independent Statement-level linear power supplies, one dedicated to the OCXO clock and the other used for powering the USB chip/5V USB line.
This is what I would expect it to have. They are capturing the USB signal and retransmitting it with presumably a more accurate clock. They also use their own independent power supply to generate the USB 5 volt signal. Any decent high-end DAC would generate its own power so not sure why this is needed.
As to reclocking, in asynchronous USB which we use today, the USB clock is only used for communicating with the host to gather the audio data. The DAC has its own clock. A buffer holds intermediate data in case the DAC is running faster in which case, the USB interface is sped up (logically) to keep the two clocks close together. At no time is the USB clock used to drive the DAC so having a fancy clock for that would be of no audible value.
But maybe we are wrong so let's measure it.
Innuos Phoenix USB Reclocker Measurements
For this testing, I used the Topping D70s that is my desk for testing. I connected a standard USB cable, set the measurement bandwidth to 90 kHz (instead of usual 22.4 kHz) and this is what we get:
We lose good bit of SINAD due to inclusion of spikes around 50 KHz due to lack of brickwall filtering. I increased the bandwidth to deal with claims that there is some kind of ultrasound components due to USB that needs to be fixed.
To give the Phoenix every chance to do its thing, I created a nasty USB cable chain. I used two USB mating cables to build a 4-segment USB cable. The intermediate connections will cause impedance mismatch and reflections. This should degrade the USB clock fairly well. Let's test the D70s with this ridiculous USB cable:
Other that negligible run to run variations, the D70s handled the degraded USB signal with aplomb, generating the same results as far as noise and distortion.
Let's now insert the Innuos Phoenix in this chain, at the end of the long cable:
As expected, it made no difference. Thankfully it didn't get worse either (I have tested USB reclockers that did make things worse).
After running the above tests, I found another USB cable extender. I attached it and called this cable "Frankenstein."
We now have 6 cable segments and some 10 to 15 feet of length. Let's compare again:
Once again there is no difference. The D70s is very capable of extracting USB data.
Claims of jitter difference is always made in these cases. Let's run the jitter test with wider bandwidth than normal:
As you can see, the two are overlaid right on top of each other. Not a single artifact is changed. Nor is the noise floor any different.
Oh, I know what you are asking: "how about music?" Well, we do have a complex test tone, the multitone, which mimics such. This is its time and frequency domain make up:
Looking at the left, you can see that it is nothing like a single sine wave.
Here is the D70s by itself and then with Innuos Phoenix:
Performance is superb either way with nearly 22 bits of distortion-free range!
Innuos Phoenix USB Reclocker Listening Tests
I connected the output of the D70s to Topping A90 and drive my Dan Clark E3 headphone with it. This is an excellent closed back headphone. This means it isolates environment noise that you would have with speakers, allowing you to much more into the noise floor of the music. It also has lower distortion than just about any speaker so please don't say this testing should have been done with speakers. Headphones are the gold standard in audibility tests of small impairments.
Since I already had the D70s looped through Innuos Phoenix, I started with this chain. I queued up one of the popularly played "audiophile" tracks and listened. It sounded fine.
I then pulled the Innuos out and connected the D70s direct using the same Frankenstein USB cable. I was immediately impressed with the difference: the volume appeared louder, and noise floor sank very low. I was able to hear very subtle differences that I had not heard when I had the Innuos being in the loop!
Let me repeat: the chain that sounded worse was with Innuos! Why did I hear a difference? The measurements indicate that none should be audible. Well, the brain is not influenced by just sound. When I changed the setup to just D70s, my mind became a detective, focusing and analyzing the track I was listening to. Not surprisingly, it started to hear detail, openness, air, etc. that it missed the first time. In other words, the comparison is invalid because the state of the brain is changing due to test being sighted.
Conclusions
As a matter pure engineering, we know a reclocker can't do much because as I explained, the DAC clock is independent of USB. Sure, there can be noise that can bleed from USB clock onto the main clock or analog output of the DAC in less than well designed products. But why would you start with such a poor DAC? The D70s costs 1/7th of the cost of the Phoenix. It clearly has circuitry to deal with noise and clock issues of USB. You can get an $80 DAC that is so situated based.
Even when trying to create an unrealistic situation, the D70s handled the USB signal perfectly. Seeing how everyone likely has a single 3 to 6 foot cable, we have huge amount of headroom here. Should the USB signal degrade too much, you will clearly hear artifacts in which case, you should get a standard USB hub/repeater for next to nothing instead of spending so much on Phoenix reclocker.
Company can also dispute all of this by a) providing their own measurements that show any improvement in the output of the DAC and b) performing blind listening tests showing audible. Instead, the website is bare with nary any information beyond what I post in the introduction. They do quote some reviews that talk like I did in my listening test section. My testing validates the imaginary improvements one can hear. So that is not of any value.
I can't recommend the Innuos USB Reclocker. It is huge amount of money to solve a problem that doesn't exist.
EDIT: Video review is out:
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The front panel is quite attractive and gives the impression of a high-end product. Alas, I would have expected to see an indicator that the unit is on, and another that would say it is doing something useful (clocking). The back panel is sparse as well:
Not happy about the stamped sheet metal enclosure and crooked safety sticker. And what is there to read in the manual? It is just a couple of pages and says to connect the source to the USB In and the DAC to USB Out. Pretty sure if you don't know this, you need to get out of computer audio.
If you don't know what this box does, here are the statements from the company:
Innuos applied 3 main design approaches learning from their experience with the Innuos flagship music server, the STATEMENT:
01.
The USB chip regenerating the signal contains no switching regulators. All 3 independent voltages to the chip originate from an independent linear power supply with further regulation provided by 3 sets of LT3045 regulators.
02.
The use of a 3ppb OCXO clock running directly at 24MHz and connected via a board track just a couple of inches away from the USB chip. Therefore, no precision is lost within cables and connectors, as is the case when using an external master 10MHz clock with an additional 24MHz clock generator.
03.
Two independent Statement-level linear power supplies, one dedicated to the OCXO clock and the other used for powering the USB chip/5V USB line.
This is what I would expect it to have. They are capturing the USB signal and retransmitting it with presumably a more accurate clock. They also use their own independent power supply to generate the USB 5 volt signal. Any decent high-end DAC would generate its own power so not sure why this is needed.
As to reclocking, in asynchronous USB which we use today, the USB clock is only used for communicating with the host to gather the audio data. The DAC has its own clock. A buffer holds intermediate data in case the DAC is running faster in which case, the USB interface is sped up (logically) to keep the two clocks close together. At no time is the USB clock used to drive the DAC so having a fancy clock for that would be of no audible value.
But maybe we are wrong so let's measure it.
Innuos Phoenix USB Reclocker Measurements
For this testing, I used the Topping D70s that is my desk for testing. I connected a standard USB cable, set the measurement bandwidth to 90 kHz (instead of usual 22.4 kHz) and this is what we get:
We lose good bit of SINAD due to inclusion of spikes around 50 KHz due to lack of brickwall filtering. I increased the bandwidth to deal with claims that there is some kind of ultrasound components due to USB that needs to be fixed.
To give the Phoenix every chance to do its thing, I created a nasty USB cable chain. I used two USB mating cables to build a 4-segment USB cable. The intermediate connections will cause impedance mismatch and reflections. This should degrade the USB clock fairly well. Let's test the D70s with this ridiculous USB cable:
Other that negligible run to run variations, the D70s handled the degraded USB signal with aplomb, generating the same results as far as noise and distortion.
Let's now insert the Innuos Phoenix in this chain, at the end of the long cable:
As expected, it made no difference. Thankfully it didn't get worse either (I have tested USB reclockers that did make things worse).
After running the above tests, I found another USB cable extender. I attached it and called this cable "Frankenstein."
We now have 6 cable segments and some 10 to 15 feet of length. Let's compare again:Once again there is no difference. The D70s is very capable of extracting USB data.
Claims of jitter difference is always made in these cases. Let's run the jitter test with wider bandwidth than normal:
As you can see, the two are overlaid right on top of each other. Not a single artifact is changed. Nor is the noise floor any different.
Oh, I know what you are asking: "how about music?" Well, we do have a complex test tone, the multitone, which mimics such. This is its time and frequency domain make up:
Looking at the left, you can see that it is nothing like a single sine wave.
Here is the D70s by itself and then with Innuos Phoenix:
Performance is superb either way with nearly 22 bits of distortion-free range!
Innuos Phoenix USB Reclocker Listening Tests
I connected the output of the D70s to Topping A90 and drive my Dan Clark E3 headphone with it. This is an excellent closed back headphone. This means it isolates environment noise that you would have with speakers, allowing you to much more into the noise floor of the music. It also has lower distortion than just about any speaker so please don't say this testing should have been done with speakers. Headphones are the gold standard in audibility tests of small impairments.
Since I already had the D70s looped through Innuos Phoenix, I started with this chain. I queued up one of the popularly played "audiophile" tracks and listened. It sounded fine.
I then pulled the Innuos out and connected the D70s direct using the same Frankenstein USB cable. I was immediately impressed with the difference: the volume appeared louder, and noise floor sank very low. I was able to hear very subtle differences that I had not heard when I had the Innuos being in the loop!
Let me repeat: the chain that sounded worse was with Innuos! Why did I hear a difference? The measurements indicate that none should be audible. Well, the brain is not influenced by just sound. When I changed the setup to just D70s, my mind became a detective, focusing and analyzing the track I was listening to. Not surprisingly, it started to hear detail, openness, air, etc. that it missed the first time. In other words, the comparison is invalid because the state of the brain is changing due to test being sighted.
Conclusions
As a matter pure engineering, we know a reclocker can't do much because as I explained, the DAC clock is independent of USB. Sure, there can be noise that can bleed from USB clock onto the main clock or analog output of the DAC in less than well designed products. But why would you start with such a poor DAC? The D70s costs 1/7th of the cost of the Phoenix. It clearly has circuitry to deal with noise and clock issues of USB. You can get an $80 DAC that is so situated based.
Even when trying to create an unrealistic situation, the D70s handled the USB signal perfectly. Seeing how everyone likely has a single 3 to 6 foot cable, we have huge amount of headroom here. Should the USB signal degrade too much, you will clearly hear artifacts in which case, you should get a standard USB hub/repeater for next to nothing instead of spending so much on Phoenix reclocker.
Company can also dispute all of this by a) providing their own measurements that show any improvement in the output of the DAC and b) performing blind listening tests showing audible. Instead, the website is bare with nary any information beyond what I post in the introduction. They do quote some reviews that talk like I did in my listening test section. My testing validates the imaginary improvements one can hear. So that is not of any value.
I can't recommend the Innuos USB Reclocker. It is huge amount of money to solve a problem that doesn't exist.
EDIT: Video review is out:
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Last edited:
