This is a review and detailed measurements of NuPrime uDSD DAC and headphone amplifier. I purchased this summer of last year from Amazon for USD $179 including Prime shipping.This is a cute and very sturdy portable amp and dac:It has really beefy RCA connectors in the back, the likes of which I have only seen in Khadas Tone Board. They would feel at home in gear retailing for a lot of money.The enclosure is metal and while it is sturdy, cables can pull it around some.Let's get into measurements and see if she is worth the extra premium over cheaper offerings.As usual I start with Dashboard measurements and there, I was initially very unimpressed with the results:Remembering that some devices deteriorate in performance when their volume control is at max -- even though I am testing RCA out -- I lowered the volume to min and the situation improved significantly:This is now pretty decent with respect to distortion and noise:Jitter and noise likewise is very good:Broadband THD+N shows elevated noise in lower frequency but good performance in highs:Intermodulation distortion shows similar issue with respect to noise:Our 32-tone signal cause the uDSD fair amount of pain, resulting in elevated noise in low frequencies again and source sensitive noise modulation:Switching to headphone out, we see an "OK 5.7 ohm output impedance (prefer less than 1 ohm):The real disappointment is in power output as this 300 ohm load demonstrates:Just 7 milliwatts of power in a desktop/portable product? Can we hang our hat on at 33 ohm?Nope. Power remains quite low relative to competition. And this is on top of much elevated noise and distortion levels. Heck the Topping DX3 Pro beats it handily even in low gain mode!I started testing the NuPrime uDSD with my Sennheiser HD-650 headphones. Here the mid-range power was just enough but the moment the bass notes came in, the uDSD got severely distorted. Avoiding that distortion caused the output level to be totally unsatisfying.Switching to HiFiman HE-400i did not change the situation a lot. At modest levels, it could drive them fine but if you push it even slightly, the bass notes got distorted almost as badly as HD-650.The DAC portion of the NuPrime uDSD is fine as is its unique and quality build. The problem is in its headphone output which simply does not have enough power. Competing products like Topping DX3 Pro which go on sale at nearly the same price have far more features and tremendously better headphone output subsystem. As such, I can't really recommend this unit.My NuPrime uDSD is available for sale. Start a conversation with me if you are interested.-------------As always, questions, comments, recommendations, etc. are welcome.Please considerfunds using: https://www.patreon.com/audiosciencereview ), or https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054 ).