This is a review and detailed measurements of the all-in-one Marantz HD-AMP1 DAC and integrated amplifier. It is on kind loan from a member and retails for USD $1,100 including free Prime shipping from Amazon.The unit has a somewhat retro looking of other Marantz audio products with the round digital display and wood sides:There are both digital inputs and analog allowing one to build a complete system around the HD-AMP1. I was surprised to not see RCA outputs though so no convenient way to use its internal DAC by itself.Amplification is through class-D technology which allowed the unit to run cool. Without permission from its owner though, I did not put it through thermal stress.In addition to speaker output, there is also a headphone jack so I tested the output through that too.There is a lot of functionality in HD-AMP1. I chose to test a few of them in this feature and will test more based on requests.I started by testing the DAC+headphone stage using our usual dashboard:As you see, I set the output to 2 volt which is the nominal output of stand-alone DACs. Alas, performance is nothing to write home about. Second harmonic distortion is quite high, setting the SINAD at just 85 dB. This would put in the fourth quadrant of DACs tested (with one being the best). We also have fair bit of harmonic spikes from the power supply from 180 Hz and up (multiple of 60 Hz mains frequency in US).Loading down the headphone output with 300 ohm, we get this:There are internal gain settings but I did not mess with them. As it is, level of noise and distortion is quite high relative to desktop DAC+amp products. Power output however is decent.Switching to the power amplifier, here is the power versus distortion+noise measurement:I have plotted three graphs using three different volume controls with input being swept up to 2 volts. Distortion climbs less steeply than other amps so hard to know where to stop and measure the wattage. I selected a conservative point and got 47 watts. I believe the rating from Marantz is 70 watts using my 4 ohm load. You could certainly get there and beyond if you tolerate more distortion.As I have noted, the performance is similar to budget amplifiers like NuForce STA-200 (dashed green) but not even remotely getting close to our best in class Hypex NC400 amplifier (dashed blue). Best case performance is about SINAD of 72 dB or so.Above is with my 40 kHz AES-17 filter by the way.Frequency response was very good for a class D amplifier:And here is the broadband spectrum analysis of a 1 kHz tone:The first large spike comes at nearly 500 kHz which I am assuming is the switching frequency of its class-D amplifier. Its second harmonic is at nearly 1 Mhz and down -60 dB.Finally, here is the harmonic distortion+noise versus frequency at 5 watts of output using 90 kHz of bandwidth:Once again, it is not on the same planet as the Hypex NC400. It also has instability when the analyzer switches its frequency as indicated by the "T" symbols. It takes some 5 seconds for the readings to become stable. We saw this in the Behringer A500 amplifier review.I wanted to like the Marantz HD-AMP1. It has been in demand for quite a while on the forum to measure it. Having done that, I see no signs of excellence. It follows the drifting backward industry trend of "good enough" performance specs. This is reflected in lack of hardly any specifications provided by Marantz. On feature side, it is very strange that there is no RCA outputs to use the DAC and pre-amp with a different power amplifier.Needless to say, I can't recommend the Marantz HD-AMP1.------------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 ).