The specs say the 2192 has a "DC-coupled, fully dual-differential, matched-FET, all discrete Class-A, no-compromises analog signal path" in layman's terms, what does that mean?
Basically, it means the analog signal paths (from the line-ins to the A/D converter, and from the D/A converter to the line-outs) are as good as they can be.
Each element of the description means something different in terms of sound quality:
"DC-coupled" means there are no capacitors in the signal path to introduce phase distortion, which can smear your high frequencies and take the punch out of your low frequencies.
"Fully dual-differential" means there are two independent, identical differential circuits processing both the + and - sides of the differential signals for each input channel. Because there are two differential amps at the input, all internal signal paths are also fully differential. This reduces distortion and noise, and improves common-mode rejection and dynamic range. It also improves imaging by eliminating cross-talk between channels.
"Matched-FET" means we use high quality field-effect transistors (FETs) with matching characteristics. FETs are a special type of transistor that share the good-sounding characteristics of both tubes (low-order, "musical" 2nd and 3rd harmonics) and standard bipolar-junction transistors or BJTs (clarity, transparency, fast transient response). If FET circuits are designed correctly, they don't share any of the negative aspects of tube or BJT circuits (noise, harshness, slow transient response). However, if used incorrectly, FETs can be affected by a type of parasitic circuit capacitance (called the Miller Capacitance) which reduces transient and high-frequency response. We use a special biasing technique in our FET op-amps to eliminate this problem.
"All discrete Class-A" means there are no IC op-amps in the signal path (just individual, discrete parts), and every gain stage is pure class-A biased. Without getting too technical, class-A bias basically means the transistors are always drawing current from the power supplies, and they amplify both the positive and negative half-cycles of the signal. Standard IC op-amps use class AB biasing, which amplify the positive and negative half-cycles using different parts of the circuit. The class-A "constant-current" mode means the circuit doesn't suffer from "supply-droop" distortion when handling low frequencies and sharp transients, and there is no "cross-over" distortion inherent with class-AB IC op-amp designs. Many companies tout their circuits as "class-A", but neglect to tell you they're only using one or a few single class-A transistor stages, and the rest of the circuit is all IC op-amps. This is like calling a VW bus a racecar because it has a turbo-charged engine.
