terrapin77 OP
The DAC is currently going straight into the amp
You really need to spend just the $49 on the Schiit Sys first. ( you can send it back for full refund)
As I’m sure 100% you were "bit stripping" the dac with 5.4v output "turned way down", into the Quad which only needs 0.5v in for full clipping wattage.
Cheers George