This is a review and detailed measurements of the NAD PP 4 Digital USB Pre-amplifier and phono stage. It was kindly sent to me by a member for testing and costs US $199 on Amazon including Prime shipping (retail price $229).
I like the compact form factor:
The variable gain is nice to get the levels to be close to but not exceeding digital clipping. On the latter, it would have been nice to have an indicator.
Rear panel shows independent RCA inputs for MM, MC and Line input which is unusual:
I don't know how old the unit is but the MC to MM switch had already gone partially bad causing one channel to cut out. My just need some lubrication.
NAD PP 4 Pre-amplifier Measurements
I started my testing using Line In:
Performance sadly is pretty low, struggling to get to the equivalent 14 bits, landing the PP 4 pretty low in rankings of ADCs/audio interfaces:
Worse yet is the phase mismatch between channels. I notice this right away. I wonder why whoever designed this for NAD did not catch this simple mistake.
Frequency response is good and it indicates 44.1 kHz sampling:
IMD distortion versus level shows high noise floor (sloping down part of the curve):
All of this sets the upper limit in performance of the phono stage.
NAD PP 4 Phono Stage Measurements
Let's start with our moving magnet dashboard as usual:
Ouch. We have a ton of distortion products on top of mains hum I could not lower resulting in second lowest SINAD we have measured of any phono stage:
Side note: does the red bar look taller to you all than the green one to the left of it with the same height? It does to me.
Testing for overflow shows very low headroom which is something that we see in digital phono stages:
Fortunately tonality should be good given the nice RIAA implementation:
Yes, it is a hair rough but overall tonality should be fine.
Conclusions
It would have been nice to have an ADC with phono stage built-in. NAD gets the packaging right but good bit of performance is left on the table. Granted the LP format itself doesn't need high performance digitizer given its high grove noise and such. But it may need higher overload margin. And for line input, we surely want something cleaner even at $200 price point.
Sadly I can't recommend the NAD PP 4. I liked it going in, didn't coming out. You are better off buying a budget phono stage and an audio interface for digitization.
------------
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/
I like the compact form factor:
The variable gain is nice to get the levels to be close to but not exceeding digital clipping. On the latter, it would have been nice to have an indicator.
Rear panel shows independent RCA inputs for MM, MC and Line input which is unusual:
I don't know how old the unit is but the MC to MM switch had already gone partially bad causing one channel to cut out. My just need some lubrication.
NAD PP 4 Pre-amplifier Measurements
I started my testing using Line In:
Performance sadly is pretty low, struggling to get to the equivalent 14 bits, landing the PP 4 pretty low in rankings of ADCs/audio interfaces:
Worse yet is the phase mismatch between channels. I notice this right away. I wonder why whoever designed this for NAD did not catch this simple mistake.
Frequency response is good and it indicates 44.1 kHz sampling:
IMD distortion versus level shows high noise floor (sloping down part of the curve):
All of this sets the upper limit in performance of the phono stage.
NAD PP 4 Phono Stage Measurements
Let's start with our moving magnet dashboard as usual:
Ouch. We have a ton of distortion products on top of mains hum I could not lower resulting in second lowest SINAD we have measured of any phono stage:
Side note: does the red bar look taller to you all than the green one to the left of it with the same height? It does to me.
Testing for overflow shows very low headroom which is something that we see in digital phono stages:
Fortunately tonality should be good given the nice RIAA implementation:
Yes, it is a hair rough but overall tonality should be fine.
Conclusions
It would have been nice to have an ADC with phono stage built-in. NAD gets the packaging right but good bit of performance is left on the table. Granted the LP format itself doesn't need high performance digitizer given its high grove noise and such. But it may need higher overload margin. And for line input, we surely want something cleaner even at $200 price point.
Sadly I can't recommend the NAD PP 4. I liked it going in, didn't coming out. You are better off buying a budget phono stage and an audio interface for digitization.
------------
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/
