smsl su-8 v2 dac

In the past few days of listening to my HE560v2 the left channel would cut out and a few hours later come back. The day after it went out again and I couldn't get it to come back. My listening set up is PC to SMSL Su-8 to Cavalli Tube Hybrid to headphones. The Su-8 are also connected via...

I did a frequency response test (using miniDSP EARS & REW) on my SMSL SU-8 v2 DAC and found that the phase performance is strange. I used 2 headphones: Sennheiser HD650 & Hifiman HE-4XX, both single-ended. I also compared the SU8 to 2 other DACs: Grace SDACB & XiangSheng DA-05B. All DACs were...