NVA amplifier cases are made entirely of non-magnetic acrylic materials. The sides are bonded together with acrylic weld and the top plate with structural adhesives to avoid the magnetic contamination of steel screws. Here's what NVA Hi-Fi founder, Richard Dunn, said in 1992...
“It all started because when I first put the circuit together, I was listening to the amplifier in early bread boarded state, and I was very happy with the circuit. I designed a case, I put it in the case, and it was not as good. I could never understand this, so I started to investigate. The first thing I came up with was that it was steel that was the major problem. You see, a case of steel has a very strong effect on the sound. My theory on this is that there is a lot of magnetic field, that is not only coming off the transformer, but it comes off all AC circuits, comes off the capacitors, comes off the transistors. Now, with a steel case, it cannot get out of the amplifier, just bounces around inside, that turns the sound muddy and loses information.”
So far, so good, but while NVA acrylic cases can 'let out' internal interference, the same properties mean that external interference can be let in. This makes it important to maintain adequate spacing between components (especially those that contain transformers) and follow some common sense practices for wiring your NVA hi-fi system together...
Use tables and other furniture that allow for plenty of space between components and easy access when setting up.
If the phono stage head unit and power supply have to be side by side due to space constraints, make sure the phono stage output sockets are on the opposite side to the power supply case(s).
Keep hi-fi signal cables away from power cables.
Allow space between cables (close proximity can cause unwanted capacitance).
For best sound the amplifier should be left powered up. Electricity consumption is very low. It is for this reason that the power switch is located on the back panel, where it may not be easy to reach.
Try a Balanced Mains Unit. UK mains quality can be very poor. There's a strong possibility that you won't hear your system at it's full potential until you try our BMU.
Don't use tightly spaced metal racks. If you need a dedicated rack, buy one that is deep enough to allow easy access from the rear and with plenty of spacing between the shelves.
Don't sit head units (Phono 2 / 3, AP10H) on top of their power supplies. Use the umbilical leads provided to keep as much distance between them as possible without stretching the leads or stressing the connections.
Never twist or tie cables together - let them run independently.
Don't use cable risers - electrons don't get OCD, but snakeoil salesmen do get rich!
Don't forget to check out the extensive archive of NVA advice, discussion and user reviews at our Hi-Fi Subjectivist Forum
Stock expected - mid February NEW! Now with Toroidy Audio Grade transformer and soft-start feature. Normal mains is single ended. By changing this to balanced you remove noise and distortion. UK mains quality can be very poor. There's a strong possibility that you… read more
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