Did you try gaming too? Apex Legends happens when someone is shooting me and Tower of Fantasy when opening the menu. But when listening to music it just works and works. No clipping. I have also tried to increase buffer size if it helps but without success. What is your DAC and speaker amp?L30II is good for >300ohm loads in high gain, no clipping at all, but with lower impedance it can't provide too much current power (which is ok for budget amp's)
I have modified the DX7 Pro. I use Burson's V6 Classic opamps. I also have another unmodified DX7 Pro. I may try that if the DAC is a problem.