Although you don’t see them pictured here, those four op-amps in the middle of the board will be replaced with discrete op-amps including Burson Audio’s new V6 line. I have two V6-OPA “Bright” and V5-OPA + V5i models all from Burson. Burson Audio began releasing voiced op-amps, with Bright and Classic as the two options (V6 line only). I also have two of Orange Amplification’s discrete op-amp designs. Burson’s op-amps run around $75-$100 a pair and Orange Amplification’s are about $60 a pair.
I will be giving listening A/B comparisons with many other non-discrete, but still high end op-amps. Then I will be using a range of equipment to literally measure the performance of this DAC. I’ll send a sine-wave in one end and then read it on the RCA output jack of the DAC with my Potomac AA-51A Audio Analyzer! I’ll also be using my Agilent Discovery2 and many other pieces of equipment to give you guys a real review this time!
I hit some some really annoying speed bumps along the way including having a leg of one my Amanero’s “Golden” TCXOs break a leg. I actually got a Crystek oscillator this time after reading up on the real effects of long term vs. short term clock/oscillator stability. I went with the CCHD-575-25-22.5792 from Crystek, this only runs about $15 on Mouser.com and offers performance above most TCXO packages. More on this subject later (in the real review), but this wasn’t even the most annoying of my speed bumps with this project.
So on the front of the OLED screen (pictured above), there is an IR remote receiver/transceiver that talks with the remote control for the DAC. The long pins on this small part were extruding enough to touch the metal enclosure after tightening the screen down completely, thus causing a dead short. My buddies on FreeNode’s IRC Electronics channel called this right off the bat, it just took me a while to run it down.
It seemed like none of the hardware fit their holes, many required machining from me by hand. To mount the transformers I had to use countersinking bits to allow the DAC to sit down flat (I’ll have a video of this part and others of the construction). Then to add a female USB port from Switchcraft required cutting a 7/8″ to a 1″ round hole into a square hole! I used a titanium (coated) step bit. These are the bits that look like cones that gradually get bigger.