TOPPING D10 USB MINI DAC audio amplifier Decoder with Line out and Coaxial Optical out Support DSD256(Native) PCM32bit384kHz|Digital-to-Analog Converter| - AliExpress
Model 994Enh Discrete OpAmp
Archimago's Musings: MEASUREMENTS: Topping D10s - an inexpensive high performance basic USB DAC with S/PDIF outs. And on "perceptibly perfect" DACs.
Topping D10 balanced DAC review
5% off] Topping D10s - USB DAC with Swappable Op Amps ES9038Q2M OPA21
Review and Measurements of Topping D10 DAC | Page 19 | Audio Science Review (ASR) Forum
Sparkos Labs, Inc. Discrete op amps for amplifying audio signals