Having recently measured the regulated voltage from inside a yaion MC-300B, I found it to be way out at 526V when the schematic called for 460V. My mains is a steady 236V in Dorset with the occasional fluctuation up or down of only a few volts. All other voltages off the heaters were high too, (measured when the valves/tubes were in place). My assumption is that this over-voltage cannot be good for the electrolytic capacitors and also the sound quality, so i have decided to replace the transformer with one that has a dedicated 240volt primary and one ht secondary. I will be powering the heater circuits separately with the ability to have them on well before the ht to make everything last longer and at the same time I'm making it so the ht transformer can not be switched on unless the heaters are on as well.
A further point: I thought the UK voltage supply had to be within +10 and -6% of 230V?
A further point: I thought the UK voltage supply had to be within +10 and -6% of 230V?