Hi guys, RE the Musical Paradise DAC, I actually have MP D2 DSD DAC here, with AKM DAC chips, Mundorf coupling caps and USB input.
I am shipping the first unit today, with the following mods:
Re-biased tube analog stage (optimized for 6922 driver tubes) and replaced signal path resistors with Tantalums.
Revised power supply operating voltage as part of bias revision.
Added our own SS High Voltage Regulator circuit to provide rock solid regulated B+ to the tube output stage.
Bypassed the B+ and regulator rails with MWI custom capacitors.
It sounds MUCH better than stock now!
It is actually a well designed and built DAC. In stock form, I found the soundstage to be too diffuse and the tonal balance off. When I looked at operating bias and where the 6922's were operating on the tube curve, I could see that they were operating in a VERY non-linear region. Once this was resolved, alone, things got much better! I then added our own SSHVR (Solid Stage High Voltage Regulator) with MWI bypass and the B+ became VERY clean and VERY tight!
This translated to tighter and better defined bass and control across the frequency spectrum. The combination now, of proper operating bias, upgraded tube signal path resistors and regulated supply, gives the music a controlled but natural and organic flow.
I am very pleased with the result!
Finished photos to follow.