I wish! Essentially, it is one of the many available CD-Rom controller boards that makes the whole thing work nicely. I produced a giant PC board that makes +5, +6.3, +12, +125V all regulated to run the CD drive, its controller board, the DAC, and the tube buffer. Total parts cost for this guy was around $1500.
When Doc is done with his DAC project, I may revisit this piece and consider a revamp. For now, it uses a DAC from Scott Nixon.