After having this board collecting dust for the last year or so I thought it was time to put it to good use.I already have a very capable DAC so I was in no hurry to get it working.It is evaluation board that is essentially a full functional DAC but without the chassis,power supply and voltage regulators.
This board was designed and built by Burr Brown as a platform to evaluate the performance of the PCM1792 and offered to companies interested in using this chip in their CD/DVD players.The PCM1792 is highly regarded and used in a number of hi-end CD/DVD/SACD players.Its a 24 bit /192k Dual Differential device meaning both channels are on one chip and the outputs are balanced.
The eval board is nicely done with lots of ground plane and some high quality parts such as ELNA Cerifine electrolytic decoupling caps and some nice film caps in the low pass filter section.The input reciever chip is the Crystal CS8414 but I would have preferred they used the CS8420 for its upsampling and jitter reduction capabilities.Because the DAC chip has current outputs an op amp is needed to convert the current to voltage.Strangely for this I/V conversion BB used an op amp from a competitor the very old NE 5534. They must think its good if they used it instead of one of their own.
Thankfully all the the op amps are socketed so it will be a simple matter to try different ones.After I get acclimatized to the sound with the 5534's I will try some others.Tops on the list will be BB's own OPA627.(Their kinda pricy at $18ea and I'll need 6.)
I will be using completely separate supplies for the analog and digital section each with their own toroidal transformer.The regulators feeding the analog section will be a low noise low output impedance discrete design insted of the cheap and noisy 3 IC pin regulators.It is shown in pic #5
Pic #1-3 shows the DAC board, and #4 is the transformer and the 5 volt IC regulator
for the digital section.