Serge Auckland wrote:

I don't understand what you hope to achieve by changing the transformer.
Apart from the inconvenience of the on-off switch, what is it about the
present arrangement that is inadequate? If you want to add an on-off
switch, then why not make a small mains extension, and put a torpedo
switch near the socket, and position it where you can conveniently reach
it and switch it off when not in use? A new transformer won't be
significantly more efficient than what you have. A bigger one will be
less efficient at lower draws, and as mentioned above, will have an
increased voltage and stress the DAC components more. If you're
concerned about the total carbon footprint of each item, then throwing
away something existing and buying something new will increase the total
carbon footprint, and you won't recover this unless the new one is a lot
more efficient than the old, which is unlikely.

The on/off switch is my main complaint, but I can't help feeling like
the power supply was done by Cambridge Audio on the cheap. For instance,
sometimes the sound drops out for a fraction of a second when I switch
my CRT TV on. I refuse to believe that the design of this PSU cannot be
improved upon.

I am now thinking of moving the transformer part into something like an
old computer power supply which conveniently already has a physical
on/off rocker switch. There must be some modification I can make to at
least improve the sound a bit. Adding capacitors?

Seems you're making this much more difficult than it needs to be.

I seem to subconciously choose the hard way in life!