This is a bare PCB of an audiophile grade stereo preamplifier. Each channel makes use of a single low noise tube to implement the amplification. Either 6922 or 6N11 can be used. The preamplifier can allow balanced or unbalanced input. The output is in unbalanced mode. This allow for the input of any balanced and unbalaned sources. Supply voltage : rail voltage - AC 48V to 90V; filament voltage - AC 6.3V Board Dimension : 152mm x 136mm. Board Thickness : 2mm Copper thickness : 75um ( 4 times normal thickness) ; gold-plated surface. We provide schematic and part list to buyers by EMAIL, attaching the information to the shipment notice. We do air shipping worldwide at US$4.50. We welcome combine shipping. Track Page Views With Auctiva's FREE Counter Powered by SoldEazy