This is a review and detailed meausrements of the Roksan Attessa streaming stereo amplifier with phono stage. It was kindly drop shipped to me by a member and costs US $3,199.
Company nails the "high-end lifestyle" look with this differentiated and attractive style. I like the feel of the main control knob but the likes stop there. A tiny orange OLED (?) display behind that sticker is the only user interface. I can't imagine a streamer in this and age to have such a tiny and non-informative display. Product is designed in UK but manufactured in China which I find surprisingly at this price:
I was disappointed that no balanced inputs are provided, nor is there a USB DAC interface. Company website said there was an update and said mostly to use the app to get it. So I downloaded and ran it. It found the unit which was nice. But then it asked me for a Bluetooth pin that I could not find in the manual! How did it find it without Bluetooth? Over Ethernet? If so, why does it need Bluetooth to continue? Anyway, I had to ditch the app. Manual has cryptic instructions for firmware update using the power button. I followed that and I *think* it updated. Net, net, very poor experience overall.
I warm up amplifiers at 5 watts for a few minutes. I was shocked that while producing this level of modest power, the right side of the amplifier was almost too hot to touch! Underneath those vents is a compact heatsink. If the case is so hot, I can just imagine how hot the heatsink had gotten and with it, the junction temperature of the output stage.
Edit: could not test streaming because Roon complained that their endpoint implementation was not certified.
Roksan Attessa Measurements
As usual we start with our dashboard. Unit ships with variable gain with default of Low. Having no idea how to change it, I ran with that and adjusted the volume to get 29 dB gain:
Upon seeing all that low frequency noise, I thought I could reduce it with various grounding schemes. But nothing made any difference whatsoever. What you see is intrinsic to the amplifier, picking up power supply noise that way. The noise then overwhelms distortion but even that metric is not that great. Overall showing is very poor for an amplifier in this price range:
I wanted to see if it operated better with digital input so connected Toslink input and disconnected RCA cables as to eliminate any chance of ground loops. Identical performance was seen:
Edit: forgot to post the SNR graphs:
The "good" news here is that the DAC is much better than the amplifier so it is not the bottleneck (see measurements later). From here on, I stayed with analog input so that we can compare performance to other amplifiers. Here is our frequency response:
Strange to see a slight peaking of the response below 20 Hz. Overall response is flat enough and not load dependent which is likely due to class AB design.
Crosstalk was about average (which is again poor for this class of product):
19+20 kHz intermodulation test shows good performance:
This is due to no rise in distortion with frequency as we see in multitone test:
In other words, performance is good at high frequency, but so so at lower.
With the compact traditional amplifier in there I didn't expect a ton of power and that proved to be the reality:
Ditto for 8 ohm:
Sweeping power with different frequencies showcases the frequency independence:
I saw this strange pattern on the blue channel during warm up:
I measured the highest levels I have seen for both power on and off:
So best not have sensitive speakers paired with this amplifier.
Roksan Attessa DAC Measurements
I ran a quick dashboard measurements on the DAC, measuring the preamp output:
Quite disappointing performance although as noted, better then amplifier:
Didn't see the need to keep going.
Conclusions
I really like the look and feel of the Attessa amplifier. It is slick and modern. Sadly the likes stop there. Out of box experience with the app was very poor. The user interface dates back to 1980s. And measured performance shows an amplifier with major weaknesses in noise and distortion. It also runs hot despite not being very powerful.
Company needs to ditch the amplifier and put in a performant class D amplifier in there. No lifestyle product should run this hot and at this price point, they can easily afford a proper class D amplifier. While there, get a proper DAC in there or license one for $99.
I just can't see a reason to recommend the Roksan Attessa streaming amplifier. It is clear all the innovation went into the looks of the unit, and not performance or ease of use.
-----------
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/
Company nails the "high-end lifestyle" look with this differentiated and attractive style. I like the feel of the main control knob but the likes stop there. A tiny orange OLED (?) display behind that sticker is the only user interface. I can't imagine a streamer in this and age to have such a tiny and non-informative display. Product is designed in UK but manufactured in China which I find surprisingly at this price:
I was disappointed that no balanced inputs are provided, nor is there a USB DAC interface. Company website said there was an update and said mostly to use the app to get it. So I downloaded and ran it. It found the unit which was nice. But then it asked me for a Bluetooth pin that I could not find in the manual! How did it find it without Bluetooth? Over Ethernet? If so, why does it need Bluetooth to continue? Anyway, I had to ditch the app. Manual has cryptic instructions for firmware update using the power button. I followed that and I *think* it updated. Net, net, very poor experience overall.
I warm up amplifiers at 5 watts for a few minutes. I was shocked that while producing this level of modest power, the right side of the amplifier was almost too hot to touch! Underneath those vents is a compact heatsink. If the case is so hot, I can just imagine how hot the heatsink had gotten and with it, the junction temperature of the output stage.
Edit: could not test streaming because Roon complained that their endpoint implementation was not certified.
Roksan Attessa Measurements
As usual we start with our dashboard. Unit ships with variable gain with default of Low. Having no idea how to change it, I ran with that and adjusted the volume to get 29 dB gain:
Upon seeing all that low frequency noise, I thought I could reduce it with various grounding schemes. But nothing made any difference whatsoever. What you see is intrinsic to the amplifier, picking up power supply noise that way. The noise then overwhelms distortion but even that metric is not that great. Overall showing is very poor for an amplifier in this price range:
I wanted to see if it operated better with digital input so connected Toslink input and disconnected RCA cables as to eliminate any chance of ground loops. Identical performance was seen:
Edit: forgot to post the SNR graphs:
The "good" news here is that the DAC is much better than the amplifier so it is not the bottleneck (see measurements later). From here on, I stayed with analog input so that we can compare performance to other amplifiers. Here is our frequency response:
Strange to see a slight peaking of the response below 20 Hz. Overall response is flat enough and not load dependent which is likely due to class AB design.
Crosstalk was about average (which is again poor for this class of product):
19+20 kHz intermodulation test shows good performance:
This is due to no rise in distortion with frequency as we see in multitone test:
In other words, performance is good at high frequency, but so so at lower.
With the compact traditional amplifier in there I didn't expect a ton of power and that proved to be the reality:
Ditto for 8 ohm:
Sweeping power with different frequencies showcases the frequency independence:
I saw this strange pattern on the blue channel during warm up:
I measured the highest levels I have seen for both power on and off:
So best not have sensitive speakers paired with this amplifier.
Roksan Attessa DAC Measurements
I ran a quick dashboard measurements on the DAC, measuring the preamp output:
Quite disappointing performance although as noted, better then amplifier:
Didn't see the need to keep going.
Conclusions
I really like the look and feel of the Attessa amplifier. It is slick and modern. Sadly the likes stop there. Out of box experience with the app was very poor. The user interface dates back to 1980s. And measured performance shows an amplifier with major weaknesses in noise and distortion. It also runs hot despite not being very powerful.
Company needs to ditch the amplifier and put in a performant class D amplifier in there. No lifestyle product should run this hot and at this price point, they can easily afford a proper class D amplifier. While there, get a proper DAC in there or license one for $99.
I just can't see a reason to recommend the Roksan Attessa streaming amplifier. It is clear all the innovation went into the looks of the unit, and not performance or ease of use.
-----------
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/
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