This is the stock configuration (opamps) with all switches. The unit is in perfect working order except for one of the copper contacts in the battery compartment. It's fallen off, so I hotglued a piece of metal I found lying around in it's place, and it works fine. It's easy to get a proper copper contact and glue it there. I doubt it'll make any sonical difference though. The glue I used comes off the casing easily.
Looking for SGD500. You can send it to Dr. Xin for a free upgrade to near SM IV level performance if you want. Unit comes with the stock adjustable wallwart charger/PSU.
