a pretty easy, zero financial investment, and GREEEIT
upgrade has so far been hidden inside my AI S400.2 amp, but today it has been revealed by chance to my greatest surprise.
what happened was that i - due to pure sound's help - got the schematics for the AI S300.2 and wanted to convert it to 110V operation for a friend, as it seemed manageable from the instructions embedded in the text of the papers. however, as it turned out, at least the S200.1 and .2 power, S300.1 and .2, and the S400.1 and .2 can not work on a different voltage than what is actually written to their backs as the transformers have no taps for a different voltage connection.
having learnt that, i wondered why then there are dotted lines around certain components in the schematics noted as "cut for 120/240V operation". there is a resistor and 2 links to be cut off the circuit noted as such, and then i gave a try to it for the voltage here is 235-238V.
it took only 10 minutes to remove the lid, cut off the pieces, then put the lid back, and switch the amp on. and THEN... believe me, my lil' ol' S400 was transformed into a miraculous wonder machine: presence, transparency, naturalness, details, space, smoothness came out of the speakers in abundance fooling me to believe a new equipment was put into my system without letting me known
i dunno what those parts had been doing in the amp, but without them a new lease of live was given to my amp. i phoned some friends owning S300, 400 and 200 amps and suggested them to do the trick - and it worked for all of them, too
thus, if there is anyone here possessing any of the above amps, and have voltage around 230+ V, do the following (all must be done in the PSU; you need ony a cutting pliers, and can do it without being deeply skilled in electronics): cut off the link next to the 0.10R or 0.15R green resistor on the right edge of the pcb, just below the diode bridge, also cut off an other link by the 5401 diode just above the 4700/6800uF caps in the direction of the output transformers, and, finally, cut off the legs of the uppermost of the piggybacking 2 pcs. 220R resistors just in front of the big blue BHC cap in the middle of the PCB. do not forget to remove the stuff and legs, too!
and now, switch the amp on, sit back - and enjoy