@PYP The Singxer is a fine bandaid but not a top shelf solution. I used several iterations and they did a fine job when I was handcuffed to USB out but also handcuffed at the time to AES in. Its a great device to convert USB to other spdif formats (AES being the one I relied upon). Im not arguing that Hans B isnt bright and sincere, I’m just saying his reviews in the future utilizing the USB output from either Grimm will be handicapped. Listen for yourself As its easy to compare with a Singxer….connect it and listen back to back with the AES/RCA outputs of the MU1 into your dac. Disbale the fs upsampling out from the MU1 and connect its rca spdif to your dac. Then immediately switch to the MU1 usb to aes output of the Singxer feeding your dac. Sounds pretty good but not in the same league as the MU1 AES output.
Regarding the Muon and Muon Pro filter. I was an ealry user of the Muon when I had an Innuos Zenith. I “believe” i heard a positive difference but the more I reflect on it, I’m just not so sure. I then upgraded to the MU1 and could not discern whether there was any difference. I was then provided with an early version of the Muon Pro System. (I had also inserted a NA Rubicon swith, which is still in my setup although I cant really hear any difference today). I just couldnt hear any difference and believe me please….I LOVE to spend money on audio gear. Believe what we all want to believe….it matters not in the whole scheme of things. Grimm, Antipodes, Aurender, Taiko, et al do a wonderful job advancing the real science behind getting good sound and it certainly does no harm to insert exceptionally made cables and switches. But Hans B using the USB port out of a Grimm to evaluate anything in the future wont inform any gear decision I might contemplate.
Absolutely, MU1‘s magic is via the AES digital out (with clock signal). I also understand that Hans B is currently using the MU2’s USB out with Singxer for DAC review purposes (and luckily he still can use the MU2 to compare with other digital players, using MU2’s digital inputs).
In his reviews he covers a wide range of performance/price levels. At the time stamp ‘Then why sell?’ he explains MU1’s (magic) effect on more modest DAC’s at review (=majority of DAC’s he reviews). I can imagine that it is quite a puzzle to find a good overall balance in his more than 5 test setups/chains.
That said, he only just bought the MU2 and his test setups evolve. So I wouldn’t be surprised that later on other (higher level) D2D converters will be added in his top test setups for future DAC reviews.