Audio Note Meishu/P3/P4 instalation

ELECTRICAL KNOWLEDGE IS REQUIRED IN ORDER TO PERFORM THIS CONVERSION SAFELY. POTENTIALLY LETHAL VOLTAGES ARE PRESENT. WE CANNOT BE HELD RESPONSIBLE FOR ANY ERRORS OR ACCIDENTS THAT MIGHT ARISE WHEN PERFORMING THIS CONVERSION. IF YOU HAVE ANY DOUBT ABOUT YOUR ABILITY TO PERFORM THIS CONVERSION SAFELY PLEASE CONTACT US FIRST

PLEASE READ THE INSTRUCTIONS FULLY BEFORE COMMENCING.

KIT CONTENTS: POWER SUPPLY, 4 WAY TERMINATED CABLE, RUBBER GROMMET, HEAT SHRINK, IEC MAINS LEAD. TOOLS REQUIRED. SOLDERING IRON, PLIERS, ALLEN KEY, SOLDER, ELECTRIC DRILL, 10mm DRILL BIT.

DISCONNECT THE AMPLIFIER FROM THE MAINS BEFORE BEGINNING.

If the unit has been used recently, allow sufficient time for the power supply capacitors to discharge before beginning (5 mins is usually sufficient).

This is a two stage conversion. Stage 1 disables the on-board high voltage supply and connects the new off-board supply. Stage 2 enables remote switching of the new supply from the amplifiers on-off switch.

Stage 1.
Remove the lid and locate the printed circuit board (PCB) that carries the 5U4G valve rectifier and remove the 5U4G.
Drill a 10mm hole in the back or bottom of the amp such that the umbilical can easily reach this PCB. Fit the grommet and feed in the umbilical cable. Solder the RED wire of the umbilical to Pin 8 of the 5U4G valve base. Short out the 47R 6W Green vitreous enamel resistor that is also connected to this pin.

Locate the PCB that carries the electrolytic power supply capacitors, normally 220uF/450V or similar and solder the GREEN wire to the negative (-ve) terminal of one of these capacitors or to the solder pad that carries a black ground wire or the fuse holder that sits in the mains transformer H.T. centre tap circuit (if you are in any doubt about which wire or pads are ground connections check them as follows: With an electrical meter, set it to measure resistance and place the BLACK probe in a BLACK speaker terminal. Place the RED probe on the pad or wire in question and measure the resistance. A zero Ohm reading indicates a Ground point.). This completes Stage 1.

DO NOT REPLACE THE 5U4G

Stage 2.
Locate the vertical PCB on the back panel of the amplifier. The top right hand corner of the board will contain two solder pads (with wires attached) that are the heater supply for one of the 300B's. Without removing the existing wires or causing solder to flow between the two pads solder the YELLOW wire to the bottom pad and the BLUE wire to the top pad. Again, check the existing wires are still connected. Dress the new cables tidily, replace the lid and connect the newly installed umbilical lead to the Border Patrol supply. Replace the mains leads to both units. Switch on and amplifier should be ready to play after about 30 seconds. Good listening.