after all these years we have finally found a solution for the power supply modules at a rational price. which means we can make a transportable electrostatic amplifier.
similar to srmxh,srm252,srm270 etc. 3 times the power, +/-400v power supplys, no obsolete components etc. designed to be mounted to the bottom as a heatsink with silicone thermal sheet in between. should be about $250 in parts unless you go nuts with the volume pot. not sure of casing yet.