This is a review and detailed measurements of the new Topping DX7 Pro DAC and headphone amplifier. It was kindly sent to me by the company. The DX7 Pro costs US $599 but they usually go on sale for less on sites such as drop.com.The DX7 Pro has the most refined look of any Topping produce with the curved machine front giving it an elegant look:There are small touches such as beveled volume control edge which helps you grab it there and quickly jog it to the volume you want. The wheel is very responsive allowing you swiftly change volume despite its wide range of 0 to -99 dB.The same remote that powers the rest of Topping line is included. Indeed I used my Topping DX3 Pro remote to control it.The back panel shows high quality connectors and construction:Bluetooth seems to have become a standard feature now in Topping product (I did not get a chance to test it though). In my book any DAC over a few hundred dollars should have balanced XLR outputs which the DX7 Pro has.The inclusion of AC mains power supply means no dongle hanging from the unit.Overall, the mechanical look and feel is very solid and unit easy to operate with the remote.While Topping provides drivers, I used the Windows 10 class drivers with no issues.As usual, we start with our dashboard while feeding the unit via USB and measuring what comes out of XLR output:Great to see 4 volt output right on the money. But even greater is the incredibly low distortion spikes that are clocking at less than -132 dB or so! SINAD is the amplitude of our 1 kHz tone relative to both noise and distortion. It is translating into 119 dB which means it is the noise that sets that, not distortion. With best case threshold of our hearing being -116 dB, there just isn't any audible noise or distortion here.The noise is however a bit higher than our best in DAC ever, placing the DX7 Pro just a hair below the peak:The DAC above it costs almost twice as much so this is a great accomplishment.Back to noise, here is our dynamic range:This is an excellent number although about 5 dB worse than our best of the best.Jitter test shows some inconsequential mains related noise spikes:Intermodulation+noise shows the slightest hint of famous ESS DAC IMD Hump where distortion rises at mid levels. Topping has done a great job of suppressing this:As a result the DX7 Pro essentially outperforms its smaller brother, DX3 Pro in the entire range.Linearity shows perfection in one channel but slightest deviation in the other:My cutoff is 0.5 dB so we can still consider the DX7 Pro resolving the full 120 dB which translates into 20 bits of accuracy.Simulating "music" using 32 tones shows us very low levels of intermodulation distortion:High frequency tones do generate ultrasonic tones which thankfully we don't hear but impacts THD+N versus frequency:Edit: forgot to include the filter response in the original review:Measuring noise when the unit is outputting very little voltage (50 millivolts) gives us very good but not great results:The gain setting I suspect is just a digital attenuation so doesn't get a chance to reduce the noise level like an analog control in a dedicated headphone amplifier could.Power into 300 ohm using 1/4 passes my 100 milliwatt requirement meaning it can easily power high impedance headphones to super loud levels:I only plotted the more noisy channel as inclusion of the other made the graph hard to read. The omitted one was better performing. Basically we have the same performance as the DX3 Pro but with reduced distortion at the highest volume.Switching to the other extreme and testing with a 33 ohm load emphasizing current delivery we get:Here the noise level was higher but again, distortion was lower at the extreme compared to DX3 Pro.Switching to 50 Ohm load and measuring both 1/4 and XLR balanced output shows that the latter produces more power:At 1.6 watts, the XLR output easily clears my 1 watt hurdle for power needed to drive low impedance headphones well. And we also get lower noise to boot.Channel balance shows perfection due to digital level control in the DAC:Which is a great advantage of these DAC+Headphone amplifiers over most dedicated amplifiers.Output impedance is a bit high though:If your headphone has an impedance curve that is a) less than 60 ohm and b) is not flat, then its frequency (for better or worse) may change a bit.I started with my very low impedance (25 ohm) closed back Drop Mrspeakers Ether CX using XLR "balanced" headphone output. In high gain the DX7 Pro had no trouble pushing these headphones to skull resonating level.These are tough to drive headphones but despite that, there was no issue whatsoever in driving them to get maximum bass punch, detail and fidelity.Next up was the Sennheiser HD-650 which the DX7 Pro drove with fantastic dynamic range, detail and performance. You just listen for a few seconds to know that the amp is both transparent and the boss.So subjectively, there is no concern whatsoever in driving such low and high impedance headphones to very high, ear damaging levels.The Topping DX7 Pro betters the DAC performance of all the produces Topping had produced. On SINAD measurement, it lands in the coveted range of near 120 dB, proving beyond a shadow of doubt that it is transparent to any content you attempt to play. This is a super challenging bar to reach and I congratulate Topping for getting there.The headphone is a step below state-of-the-art from measurement point of view. Subjectively however, it is very powerful and clean and satisfies every need I personally have. Some of you know that I use a Topping DX3 Pro as my everyday DAC and headphone unit. Given the performance of the DX7 Pro, looks and usability, I am going to replace that with DX7 Pro.Needless to say,------------As always, questions, comments, recommendations, etc. are welcome.It was bound to happen: the panthers have unionized and now demanding raises through collective bargaining. They are threatening a walk-out leaving me with no panthers for product reviews. In other words, they have me by the neck. So, pleasegenerously to keep them modeling for us using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/