NFB-12. An updated version was introduced shortly afterwards with switches for the digital filters, and it looks now to no longer be available at all.
John was kind enough to pass this unit on to me and I have it my bedroom system now. I use it mainly as a stand alone DAC while John, to my knowledge, was using it as a headphone source. The headphone amp is very detailed, but not the last word in musicality. The DAC itself is very nice with a warm, full bass presentation that is the epitome of the Wolfson DAC sound, therefore I feel as though Mr. Qinghua got the most out of this DAC for the price. I haven't purchased his more expensive offerings, the NFB 12 was replaced by the 12.1, and now the NFB-15.32 which appears to be out of stock, possibly discontinued. The switchable output filters got mixed reviews anyway.
It seems as though he is pushing his ES9018 implementations as the best for sound quality, which brings this post full circle back to the OP. The Compass 2, his most configurable preamp/Dac (custom USB drivers, custom Op amps, custom DAC chips with a preamp function for one analog input) has the option of ES9018, dual WM8741 Wolfsons, or the highly regarded PCM5102 chip and Mr. Qinghua recommends the Sabre chip as the best sounding. The unit runs between $399 and $499 depending on chip or options, and at first glance appears to be right in the heart of the price vs performance offering from Audio GD. No SMD's, all Wima caps, Dale resistors, etc. The NFB-11.32 is a great bargain at $299, but I think I'd recommend moving up one step to the better parts quality in the Compass 2.
