NVA has a unique design philosophy that would put many a high-end manufacturer to shame:
- The cases are made entirely of non-magnetic acrylic materials.
- The case sides are bonded together with acrylic weld and the top plate with structural adhesives to avoid the magnetic contamination of steel screws.
- The circuit boards are similarly bonded to the case, themselves bonded to the internal or external heatsinks.
- The output transistors, beefy 10 amp Darlingtons, are also bonded to the heat-sink using heat transfer adhesives.
- No surprise. The diode bridge is also bonded to the case bottom, as are the power supply caps and the transformer.
- Internal high current wiring from the power supply is uncoated, stiff solid-core coated copper of approximately 14 gauge. A real bus. No coating beats even Teflon. The resulting girder-work makes any NVA kit amp a unique proposition to look at with the lid off. However amps are glued shut to keep out the curious.
- The input selector switch, where fitted, is wired to the input RCA jacks with teflon-coated, silver plated copper wire, as is the connection from selector switch to the volume control and thence to the input on the circuit boards. A small compromise.
- The volume control is either high quality plastic film or stepped attenuators types for minimal aural impact. The pot's tracks are specified to Log A to achieve close channel tracking.
- No attempt is made to add output compensation networks, such as an inductor or parallel capacitor network or even fusing. Therefore, the amplifier is not unconditionally stable, and requires low capacitance speaker cable. NVA's LS series cable is the natural choice. It has a separate positive and negative cable for each channel to minimize capacitance, about 7pF per foot, and is made up of individual silver alloy solid core conductors in a black woven sheath terminated in Z plugs.
- NVA assumes that you as the owner will read, understand and heed the caveats regarding speaker wire and not short-circuiting the outputs, in order to obtain truly high-end performance at a fraction of its normal cost. Remember, the payoff is wonderful sound.
- There are NO adjustments for DC balance or output bias current settings -- nothing to go wrong or drift with age. Nevertheless, the amplifiers are direct-coupled, no coupling capacitors to colour the sound. All circuit board electrolytics are bypassed by large value polystyrene caps, to filter the supply over a wide band.
- All NVA amps are quiet -- extremely so.