Greetings!

Have an interesting situation here. Own Buffalo II DAC for several years (2nd owner). It's powered from half of the LCDPS (version with 2 power resistors) and have full set of first rev (probably) Trident regulators. USB interface (JLSounds I2SoverUSB v.III) powered from another half and is configured for ES90XX. DAC (with power transformers and PSUs) is assembled in a shoes box with double aluminum foil coating. ES9018 chip covered with flat 1,5mm cooper heatsink (grounded).

The thing is, while playing Hi-Res PCM audio (88.2Khz+) over I2S, I have frequent lock drops. While 192Khz, lock is missing, inconsistently, for about 30 times per minute. 384Khz is unplayable. DSD64 and DSD128 over the same connection is super stable. Consumer level and TTL level SPDIFs are stable too at 192Khz. I have two sets of I2S cables: one from CAT6 0,52sq.mm twisted cooper wires and another from coax 50 ohm silver-plated RG178 cables. Both less than 10cm and all wires have equal size. Both sounds equally. Tried different XMOS based interfaces - same problem.

Any ideas, what might cause this behavior?

P.S. Previous owner used it in SPDIF coax only mod. IDK, how this could affect, but still.

UPD: Problem solved. Bought new Attiny85 and flashed it with hex from download section on Documents page.

Edited by user Sunday, April 5, 2020 11:06:04 AM(UTC)  | Reason: Not specified

K, I have an update. Measured voltage on 1.2v Tridend shows significant drops when playing content over 192k (very distorted noise like sound). After going back to stock for 1.2v rail, I'm actually able to play 300k+ content (with very frequent unlocks, but still). There still unlock issues on 192k, but is noticeably better then previously. A year a go playing 192k content were much stable. Removing other Trident regulators gave no improvement.

So, here are options left to do:
1. Swap AVCC module (I have ~3.49v on AVCC pin)
2. Swap XO
3. Swap ES9018S IC for new one ore ES9028Pro
4. Desolder input terminals and try direct wire soldering.

What do you think would benefit the most for this issue?

Problem solved. Bought new Attiny85 and flashed it with hex from download section on Documents page.