My journey of Totaldac started with a D1-Dual and a reclocker, which I loved. I upgraded to D1-Six after holding off for more than a year. For my listening preference, I had reservations with the Six for classical and choral music. I considered the sweet sounding Linn Klimax DS/3, but could not accept the unilateral connector orientations and also valued D1-Six more for dimensionality and transparency. I inquired and learned about the D1-Seven project in July 2017 which I kept quiet for Vincent. I finally upgraded to D1-Seven recently after saving. Kudos to the friendly Vincent for turning around quickly. He received the Six on Saturday and I got the Seven back the following Friday. I have listened to the Seven with the Gigafilter USB for three long sessions in three consecutive days so far. My impression is for the combination of Gigafilter, Totaldac reclocker (unchanged), and D1-Seven.
The combination has the following characteristics: alive in macro and micro dynamics; transparent with excellent timbre; delicate ambiance to project soundstage width, height and depth; weighty/rhythmic tones; layered presentation with my favorite mid-hall perspective; natural openness; bloom and clean textures of complex, combined voices and instruments. These characteristics are notable even over D1-Six based on memory. This setup produces the satisfaction and realism of a live orchestra, which has been illusive so far. Like good equipment, D1-Seven and Gigafilter sounded good from the start after warm-up for an hour. Some manufacturers profess that break-in is for users to adjust to new equipment. I equate that to lowering user expectation.
I had an original Totaldac USB/filter before changing to a much pricier USB cable. It was better and I would not mention the brand name. I grudgingly tried a plain-looking Totaldac Gigafilter USB, because the other brand could not supply a 1.5 meter for my new setup. I went to a concert last night including Rachmaninoff’s Symphonic Dances. I came home to compare Gigafilter USB with the other brand with the last track of Symphonic Dances and the 1st track of Belkis, Queen of Sheba on Reference Recordings 24/176 HRx. I played the two tracks once on each cable and repeated again. It was obvious on the first path that dynamics, ambiance, transparency, tone colors and soundstaging were much better with the Gigafilter. The comparison was over after confirmation in the second path. It is hard to put a sensible margin of superiority but I would venture to guess “roughly 50%”. The significant margin may have resulted from that the Gigafilter enabled D1-Seven to shine. Conversely, that cable costs 30% more than a Gigafilter.
The experience gives me newfound respect for the plain looking Gigafilter USB with, I initially thought, an obnoxious box. I contacted Vincent for an explanation. He pointed out "Try this very high end USB filter and discover the capability of your DAC" on his website. I obviously did not think much of it before. Amusingly, I moved from a DAC with a CNC aluminium chassis to Totaldac's sheet metal, dampened with a copper plate and a 3M sheet nonetheless. My reaction on seeing external/internal Totaldac pictures the first time was .."really?". Then I listened for myself, got the essence, and liked it in person.
My conclusion is straightforward. For existing owners considering a Totaldac upgrade, just save for a D1-Seven and pick up a Gigafilter. The combination is sublime. If you have a Totaldac server or another digital transport (Melco N1 ZH/2 for me), the Gigafilter USB is indispensable for an immediate improvement in the meantime. It is hard to believe the leap until an experiment. I am not interested in qualifying my opinion against other competing equipment or constantly promoting my own. As I finally hear something capable of reproducing the realism of live concerts, I will just spend more time listening.
Cheers!