4 Jan 2024 : the boards are now red in color. This is a bare PCB of a tube amplifier. Each channel makes use of a single low noise tube 6N11( or Russia's 6?23? or US's 6DJ8)at the input and proceeded by a power tube EL34 to accomplish power amplification. Depending on whether the output transformer to have center-tap or not, the board can be connected in either triode, ultra-linear or pentode mode of operation. The schematic is shown below for reference. We provide detailed schematic ( with values and rating) to buyers by EMAIL. The area enclosed in yellow line represents the traces that are included on the board. Dimension : 126mm x 185mm Board Thickness : 2.0mm Copper thickness : 75um ( 4 times normal thickness) ; gold-plated surface; double-sided solder resist coating for maximum reliability. We do air shipping worldwide at US$7.00. We welcome combine shipping. Powered by SoldEazy