The Amp section provides a pair of RCA inputs for use with the DAC, as well as RCA outputs for connection to separate powered speakers. Although there is only a single-ended input, A50s has a built-in balanced amp circuit. Therefore, it can drive single-ended headphones by 6.35mm output, and drive balanced headphones by 4.4mm balanced output. Portable Chain 1: CA Andromeda with Gold Plated OCC Silver wires + Gold Plated Silver Gold Alloy OCC Hybrid wires + OCC Silver wires -> AK SP2000 (Minimum Phase Apodizing) My current headphone amp is a Peachtree Decco2 (which I also use for desktop speakers). Its very old and likes to 'pop' when turned off. It also has groundloop noise which I haven't been able to get rid of completely. With the L50, due to the pass-through, I assume the volume knob doesn't work with the pass-through signal, as it would with the headphone output. I guess that means that to control a powered speaker with, say, a PC's streaming input signal, the volume control for the whole system could only be the PC's volume control or an external DAC, if there is one?

NFCA modules result from TOPPING’s intensive research and development into headphone amplification technology, and the flagship A90 was the first amplifier from TOPPING that incorporated these modules. NFCA modules ensure low noise levels and distortion under all conditions and when used with all headphones.And I assume the A50s, by contrast, could be the volume control for the whole system. (Or the DAC could if it has a volume knob.) Greetings bass head and welcome aboard. Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions leading to a beautiful audio experience that will make you fall in love with music… All over again so… Topping A50/D50S

Really there is very little to say here; it is a headphone amp and a fantastically transparent one. If you don’t know what an amp is meant to do, please read our explanation of how to choose a headphone amp. There’s not really much else to say with Amps & DACS like this, no matter what some audiophile a**hole says. The A50s also features a ultra wide frequency response, which exceeds the CD and Hi-Res Audio standard, which can be sent to the three outputs 6.35mm single ended and 4.4mm balanced headphone outputs and RCA pre outs. The near 0-Ohm output impedance of the A50s produces a high damping factor that minimizes frequency-based reactive-load impedance shifts and ensures a predictable frequency response. The high damping factor ensures adequate control over the connected headphone's drivers, allowing for powerful bass and accurate sound reproduction. What‘s in the box:The obvious reason is that the A50/D50s is horribly overpriced. I’d absolutely never under any circumstance fork over that much for an amp and DAC. How does it compare with the similarly priced iFi Zen CAN Signature 6XX and the more affordable E30/L30 combo? The NFCA modules of A50s are not only able to drive the headphones but also apply to be a preamplifier with the same ultra-high performance. When it is in preamp mode, output impedance is as low as 20ohm, which is widely suitable for various devices.