This is a low noise low distortion JFET-tube hybrid pre-amplifier PCB. The circuit features a low noise low input capacitance J-FET ( 2SK117) input, and followed by 12AX7 as second stage and output. On bench it achieved 0.005% THD at 1Vrms output and 0.008%THD at 2Vrms output. Sonically the preamplifier gives a wide sound stage and finesse sound. We provide schematic to buyers by EMAIL. Operating condition : +250VDC 10mA PCB thickness : 1.6mm Copper thickness : 2 ounce copper ( 70um !) plus gold plated surface for high current. We do air shipping worldwide at US$5.00. We welcome combine shipping. Powered by SoldEazy