– Audio Precision APx555 B-Series Analyzer with 200kOhm input impedance
– Audioquest Mackenzie RCA Cables (1.5m)
– APx555 Coaxial out
– Audioquest Carbon SPDIF cable
– All measurements shown in this post are taken with coax SPDIF input, 44.1khz sample rate
– ifi iPower 5v power supply
The Prozor DAC was ‘Amazon’s Choice’ for some time and is still a #1 bestseller.
It’s a low cost unit designed mostly for those needing to connect a TV which only has SPDIF out, to a set of 2.1 speakers. BUT, it’s so hilariously bad that I honestly wonder how anyone ever thought “Yes, this is a finished product”.
I gave this DAC the best possible chance, using a high quality ifi iPower power supply, and feeding it an incredibly clean, low-jitter signal from the APx555 itself (this dac does not have USB input). It’s likely that if you were to feed it 5v power from the USB port of a TV, and a high-jitter signal from a TV optical out, it would be even worse than shown below.
I’ve not done full reports for this, because quite frankly as you’ll see from the measurements below there is nothing that could possibly redeem it and I don’t think it’s worth anyone’s time.
Additionally, this is not just a dud unit, in fact this is the third unit of this DAC I’ve owned. I purchased one a year or so ago which was so awful I thought it was broken. I got that unit replaced, and it was just as bad. That particular unit has now been sent to Zeos Pantera.
A year on, I’d hoped that maybe they would have updated or fixed this product, and so I purchased another and it arrived today. So lets see how it does….
Dynamic Range (AES17): 99.9dB
Noise Level RMS (20-20khz): 8.8uVrms
Noise Level RMS (20-90khz): 170.2uVrms
DC Offset: 2.7mV Active, 2.7mV idle
Perhaps the most basic thing a DAC should do is provide a flat frequency response. Maybe some earlier treble rolloff if it’s using a slower filter or NOS, but other than that, it should be pretty flat right?
Well….what about distortion?
I’m pretty certain I could whistle a cleaner 1khz sine myself!
In fact….let’s find out…for science!
THD alone of the prozor is 5.4%:
And when whistling I could get down to about 0.3%:
Obviously when looking at THD+N I can’t get low enough cause there will always be too much noise (and width of the fundamental), but still, I thought that was pretty funny….
Anyway! What about if we turn down the signal a fair bit to make sure that it’s not just clipping? Let’s do -6dB to be safe:
A little better, but still awful!
It turns out that the dac doesn’t stop clipping until you get to about -10dB:
THD+N / Frequency:
Lots more distortion in the upper and lower frequencies.
-90.31dBfs 1khz Sine (Recorded with 192khz ADC Sample Rate):
Idle Noise Spectrum upto 1.2Mhz:
So…..in case it wasn’t obvious, this is a product so horrible it’s almost hilarious. Please please please please please do not buy this. If you need to convert SPDIF to analog for use with a TV, get something else. ANYTHING else.