It is all relative, if you think SU-1 is good, a fully modified Amanero is a cut above that, that was when I realized how much of the LKS potential performance was left on the table when using the SU-1 once I started looking at the native DSD mode on the Amanero.
For a long time SU-1 was the only native DSD option that works with the linux based streamers like the SMS-200 and the LKS.
SU-1 is a very jittery device, the link below is a measurement on SPDIF.
Given that one of the main selling features of the unit is the low jitter re-clocking the results are a disappointment.
https://www.audiosciencereview.com/...f-singxer-su-1-usb-to-s-pdif.7095/post-161505
Compare the Gustard U12 (blue) to the SU-1 (red).
This tends to aggravate certain kinds of music like the early redbook stuff.
Bass playing from a speaker in a room is part from the speaker and part the room resonance modes, it makes it hard to do a comparative evaluation.
With that said, with the SU-1 I could feel the bass going over my concrete floor and up my chair, with the modified Amanero the walls shook as well, was not expecting that from the speaker that has 2 pairs of 10in woofers.
(This is part room resonance, my room has a mode at 26Hz, there was simply not enough energy at 26Hz to excite that mode when it was playing out of the SU-1)
Hence my comment about the SU-1 being bass shy.
Real bass can definately be present on headphone as it causes the skull to vibrate, but it will not be able to shake the whole body like a standalone speaker.
If the bass performance is good on the HD800, I have found the speaker performance will good as well.
Additionally I also have the Audeze LCD3 just to make sure
Early Redbook recordings do quite well with HQP, if you use an apodizing filter to get rid of the pre-ringing in the signal.
This some of the silly stuff the industry used back in the 80's on the digital data to make it sound acceptable on cheap equipment by actually pre-distorting the signal.
The SU-1 is injecting a lot of noise into the LKS, I had it plugged into the I2S input but idle, unplugging it lifted a veil on the music.
Self noise from various interfaces is potentially a problem on the LKS,
@MartinWT noticed a similar behavior when the unused Amanero was removed from the DAC.
The updated Amanero is a much cleaner presentation, it goes the next step in extracting even more performance out of the LKS 004
...but it is not completely free from issues, I am still quite concerned with the 44k/48k loud cracks I am hearing on my unit