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This is a detailed review and measurements of the Topping DX7 DAC and integrated headphone amplifier. Frequent readers of this forum know that I am a fan of Topping D30 DAC . It measures excellently and is a bargain at $130 shipped. While the D30 has distinctly budget feel to it, such is not the case with Topping DX7. From cardboard packaging and custom foam to the heavy aluminum case the DX7 brings a much higher quality feel. It nearly rivals my Exasound E32 at 15 times the price. I purchased mine through Amazon for $299 shipped. Strangely it shows not available anymore: https://www.amazon.com/Balanced-Headphone-Amplifier-Topping-384KHz/dp/B073TRX2WC Front panel as is an OLED display which has great contrast and gives nice confidence of what is being played as far as sample rates and formats (DSD and PCM).Power supply is built-in which I appreciate very much. Topping boasts having regulatory certification which I appreciate (FCC and CE labels are underneath). It amazes me that audiophiles sweat noise/EMI yet go and buy hobbyist designed equipment that has no such certification and hence is likely to be bleeding badly on both fronts. That is on top of safety risks of mains powered equipment.The Topping DX7 comes with an amazingly high quality custom remote control. It is made out of machined aluminum with excellent button tactile feedback. This picture does not do justice to it:You can cycle through the filters with a dedicated button. The display can be dimmed but not turned off.Connectivity is superb. We have both balanced and unbalanced analog output. There is also S/PDIF coaxOn the input side, we have full array of inputs from USB to Toslink and S/PDIF Coax input in addition to balanced AES. Most excellent!The unit is heavy for its size and stays put when you mess with it.The simple printed material comes with full suite of measurements made on $28,000 Audio Precision analyzer! It shames so many high-end companies that just provide useless specs or countless hobbyist DACs or China-special products that never verified their product to work properly.Format support is also excellent with PCM sampling up to 384 Khz/32-bit and DSD up to DSD128. Wish it had DSD256 for completeness. Here is what Roon says about formats it detects from the DAC:Really, I can't find anything to complain about here. For $299 this level of quality and feature set is a steal.Due to extensive functionality of the Topping DX7 I am dividing this task into two parts. What follows is the performance measurement of the DAC portion using USB and S/PDIF Coax input. In part 2, I will perform headphone measurements and comparisons.Speaking of comparisons, the natural test was against Topping's own D30 stand-alone DAC. All testing is performed fresh (i.e. D30 measured together with DX7 for every test using identical cables/setup). Windows 10 in-built USB class driver is used (i.e. nothing installed).First, our friend the J-test jitter and noise measurement at 24-bits/48 KHz sampling:Looks like we have a linear power supply in the DX7 (good) which is generating that extra blip at 120 Hz (2X mains frequency) noise component (red). Pretty harmless though at such a low amplitude. Otherwise the rest of the performance is identical. For that reason, I almost stopped here thinking the rest of the measurements would be the same. I am glad I did not as that didn't turn out to be the case.Here is a linearity test using S/PDIF input. The analyzer outputs a digital signal whose PCM representation gets smaller and smaller in amplitude. The measured analog output is compared to expected value and deviation plotted. An ideal DAC would have a flat line:We see a remarkable improvement here in low level linearity/error. The Topping DX7 performs far better, easily delivering more than 18 bits of resolution. The D30 though only does well up to 15 bits or so.Nex test is harmonic distortion of 1 Khz tone. Unlike previous measurements thought the 1 Khz tone is filtered out of the measurements. This reduces the noise level of the analyzer allowing us to really dig deep and see the spectrum of noise and harmonic distortion of the DAC being tested:We see that the Topping DX7 (in red) has much lower noise floor. Its distortion spikes are more visible as a result but most of them are lower levels than Topping D30. Using the THD+N measure we have some 7 db of improvement.Skinning this cat differently by sweeping our source signal frequency, we get a plot of distortion+noise relative to frequency:Here, I have also included the Exasound E32 as I was starting to get worried that the Topping DX7 was as good as it. Looks like it is not quite but the DX7 easily beats the D30 again.This is better seen in this new test: SMPTE IMD. This is a 60 Hz signal modulated by a 7 Khz tone with a 4:1 ratio. What is seen is the residual noise+distortion:Good to see our measurements are consistent with Topping DX7 DAC beating the D30 again by a healthy margin. The Exasound E32 does even better (sigh of relief).Here is another new measurement: phase error between the left and right channels, given identical signal:The Topping DX7 wins again but these are small numbers with the D30 maximum error of just 0.4 degrees.Lastly let's look at the frequency response measurements given the fact that the DX7 has three separate filters for PCM:I am not sure if I messed with this before or not (I think not) but the default filter was the slow roll off which in my book is too slow. I like life in fast lane so I changed it to Fast setting which has the same steep drop off as minimum phase.The topping DX7 DAC substantially raises the bar on functionality and performance in budget DACs. It is full featured and comes with everything you need. Measured performance is the best in this class so far with no fault to be seen. Yes, my $3,500 Exasound E32 beats it but this is remarkable performance at just $299 shipped!The mechanical feel, volume control, remote, etc. are all excellent.I have no choice but to declare theAs always, comments, corrections, questions, are welcome.If you like this review, please consider donating funds for these types of hardware purchase using Patreon ( https://www.patreon.com/audiosciencereview ), or upgrading your membership here though Paypal ( https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054 ).