Have been using my DX7s for almost two weeks now – got it from Amazon for $500 – arrived a couple of days before the post that Massdrop was now selling it for $379 – story of my life…
In any case I’m pretty happy with the product. As others have written it unboxes like audio jewelry 2 or 3 times the price – and looks the part as well. Can’t wait for Amir to do the teardown on HIS DX7s – the image of the interior shown on Topping’s website is tantalizing but not detailed enough.
I was using an ancient Benchmark DAC-1 until the DX7s showed up – I sent the Benchmark in to repair the pot as it would occasionally get noisy in the right channel. An equally ancient pair of Austrian-made AKG K 701’s made good music through the DAC-1 and the two have worked flawlessly for over a decade now. I also have a pair of Dynaudio Pro BM6A’s but truth be told in my current environment I don’t play them very often. They are also over a decade old so it was time to make some changes.
The DX7s was able to drive the 60-ohm AKG’s to sufficient volume – at least for my listening tastes - but the 10-ohm output impedance led to some audibly strange results with certain songs – clearly something was amiss with the frequency response curve. For some reason the even lower impedance Etymotic ER3SE balanced armature earphones did not seem to suffer the problem to the same degree but that may be due to their extreme efficiency compared to the AKG’s. Combined with their heroic levels of external noise isolation it made for a VERY quiet listening experience. But the Ety’s are for use on the road with my iPhone SE and 6th Gen iPad. They will soon be joined by the Topping NX4 DSD thanks to Amir’s positive report on that product.
Back at home it became obvious that I needed some new headphones. I had been considering the Etymotic ER4SR earphones since I loved the ER3SE’s so much but with the DX7s output impedance it made more sense to try something with higher impedance – enter the Sennheiser HD600’s. My out of the box impression – WOW! This was a MUCH better match for the DX7s except from the standpoint of headroom – on some tracks I found myself pushing the volume level above -20db on the DX7s display. The background noise was dead silent – my ears are 62-years old so you can take that for what it’s worth – and I found myself listening to CD after CD as if hearing them for the first time. It reminded me how good the DAC-1/K 701 combo sounded when I first heard them back in 2007.
Yes, you heard right, Redbox CD sound courtesy of another ancient device, a Marantz CD5001 CD player into the brand-spanking new DX7s via 1 foot of Belden 1694A coax from Blue Jeans Cable. Since the DAC-1 did not have a USB input the entire computer audio experience was unknown to me except via Apple Music from the iPhone and iPad in the last year. I did have a kluge setup with TOSLINK into the DAC-1 via a Turtle Beach Micro II USB adapter but this was completely unacceptable for music listening – good enough for YouTube but that’s about it.
But now I’ve discovered Tidal HiFi using the stock USB cable from my first ever Mac into the DX7s. I’ve set up the Tidal desktop app and I’m running it in Master with Exclusive mode and the volume maxed so the DX7s display now lights up showing 88.2kHZ or 96kHZ if I pick the right album to listen to. I finally get what the rest of you have known for a while now – maybe I’ve purchased my last CD.
About the headroom with the HD600 – or lack thereof – I got an entry-level “balanced” cable from C3 Audio and I’m now running the HD600's off the XLR connection up front. I’ve gone from 10-ohm output impedance to 20-ohm – YIKES! – but I’ve also got more drive from the second TPA6120A2 now in the loop. I’m seeing an improvement in headroom from 7db to 10db depending upon what album I’m listening to. I’ve only experimented with Tidal so far - waiting for my DAC-1 to get back so I can do some detailed comparisons between the two units using all 3 headphones. I will also loop the USB out of the DX7s via coax into the DAC-1 to see how Tidal sounds through that combination. I have no doubt that the sub-1ohm headphone amp in the Benchmark will blow away the DX7s dual TPA6120A2’s in terms of headroom and drive but I’m hoping the DX7s makes up the difference with the latest ESS DACs and associated circuitry. I’ll be sure to let you know.
Sorry my first post is so long – but it has been over 10-years since I upgraded my DAC/headphone combo so I had a lot to talk about.