This is a review and detailed measurements of the NAD 7050 integrated DAC, amplifier and streaming playback. It is on kind loan from a member. It appears the product was announced in 2014 and since discontinued as I can't find it on sale anywhere. The cost was USD $999 from what I can gather.
The unit can be used both horizontally and vertically. A rotational sensor changes the display orientation conveniently. Here is its upright position which I consider better for sound since the electrons can naturally free fall into the speaker terminals:
The outside has what appears to be some sort of rubber glued to it. It is soft to touch but picks up dirt very easily and is impossible to clean due to sticky nature of it.
The large knobs imply great feel which they don't have. They wobble as you rotate them. The larger knob is the volume control which had an odd delay in updating the display as you rotated it. Overall, a good effort has been made to create an unusual design but didn't quite get there in feel and functionality.
The back panel shows off the inputs and speaker output:
For my testing, I focused on USB input as I suspect that is the most common interface for consumers. Alas, the USB interface is class one so only goes up to 96 kHz. To get the advertised 192 kHz you need to use the other inputs. I downloaded the NAD drivers which nicely gave me ASIO interface for testing.
There is an app to control it and I downloaded it from Android play store. It is a simple remote control but allowed me to change the audio-out to be full range so I could use it for DAC testing. Otherwise it is filtered for subwoofer out. Despite its simplicity the app crashed on me once.
There is no analog input so I had do all of my testing with USB digital interface.
As expected from a brand name company, the NAD 7050 comes with full set of safety and emissions regulatory certifications.
The amplification in NAD 7050 apparently is a scaled down version of what is in NAD M2. Here is what NAD says about it:
View attachment 23134
My read is that it is a power DAC similar to
Lyngdorf TDAI-3400 I reviewed recently. Measurements will confirm if so.
DAC Measurements
As usual, where possible I try to isolate the performance of the subsystems, in this case the DAC. Here is our dashboard view using USB input/Line Out. I hope you are sitting down if you owan the 7050 and use it as a DAC:
View attachment 23135
What the heck is going on here? Even at 0 dB the unit doesn't get to 2 volts yet it severely clips resulting all of those harmonic distortions. Dialing down to -2 dBFS improved performance but just to 83 dB. By then the output voltage was even lower, making it not so useful as a DAC anyway. My thinking is that this is a split off output from the power amplifier as opposed to a traditional DAC output. I guess for the assumed subwoofer duty it may be OK.
Naturally, with the SINAD as measured falls at the bottom of the graph of DACs tested:
View attachment 23138
After the first bad impression, the 7050 almost nails the rest of the measurements such as linearity:
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And jitter:
View attachment 23137
Since USB doesn't support 192 kHz, I had to run a different multi-tone test at 44.1 kHz:
View attachment 23140
Amplifier Measurements
As usual, the dashboard view is at 5 watts of power into 4 ohm:
View attachment 23139
As power amplifier measurements go, this is not too bad actually and almost matches the vaguely stated 90 dB spec by NAD.
Power versus distortion+noise is also pretty decent:
View attachment 23141
The downward part of the curve is always dominate by noise as the output level is low. Here, that part of the curve is flatter than I am used to seeing which is good as far as level of noise. Likewise, distortion is kept under complete control until onset of sudden and massive clipping at 54 watts. This too is good (sans the clipping). Stated rating is 50 watts at 4 ohm and we beating that a bit which is nice. Then again, 50 watts is not that much power in grand scheme of things.
THD+N versus frequency using my default 45 kHz bandwidth shows pretty awful results (in red):
View attachment 23142
Suspecting ultrasonic noise at play, I re-ran the test with 22.4 kHz (as with the dashboard) in blue which shows that effect quite conclusively. One channel is worse than the other though which is strange. Note that the drop above a few Khz is due to bandwidth of the test being too low to capture all the harmonics (and hence the reason I like to use 45 kHz bandwidth normally).
Broadband FFT shows of 1 kHz tone shows us what is going on:
View attachment 23143
This is without my Audio Precision high-frequency filter (AUX-0040). All the other tests used that filter.
On the extreme left we see our 1 kHz tone as a spike rising to 0 dB or so. We have a single and large spike at 850 kHz. That seems to indicate to me that 850 kHz may be the switching frequency. Given its high frequency, the power DAC is running likely with as a single bit converter which would create a lot of quantization noise. Noise shaping is used to push that above 30 kHz or so with the peak at about 80 kHz. This is the drawback of power DACs as we have seen in the Lyngdorf and SONOS Amp versus class D amplification which doesn't need noise shaping. You can see the effect of high frequency noise in the thickened sine wave of the same signal in the inset.
Conclusions
Usually, by the time I get to the end of testing, I have a good idea of if I like or don't like a device. Here, I am not quite sure. Let's agree that no one should be using the NAD 7050 as a DAC with external amplification as NAD suggests in the manual. You will be listening to a heap of distortion products with anemic output to boot.
The amplifier seems to have some good tricks under its sleeves with lower than normal noise and very controlled distortion until a very hard limit. My issue there is the 50 watt rating for a $1000 device. That is just not enough power for a product in this category.
Seeing how the NAD 7050 is discontinued, maybe it doesn't need my recommendation or lack thereof anyway. So I will leave it at that.
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As always, questions, comments, recommendations, etc. are welcome.
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