[sdiy] power supply pain

[Tony Allgood]

>There's a +/- 18.5V regulated supply in the cabinet, and smaller +/-
15V supplies on the various PC boards. Seems to work well. Keeps the
heat on the PCB's to a minimum.

Yes, I like pre-regulators. But it does increase the overall heat
dissipation in the whole unit. You have to consider the input voltage
overheads for the both the regulators, 5V as opposed to just 2.5V for
78s, which would double the heat loss in regulator system for worse
case. However, with the newer low drop-out stuff, this is less of a
problem. Stability is worse though for the LDO regulators.

Mind you this is insignificant when you consider that for European
supplies you can get, in theory, a range from 200V to 264V from the AC
line. So you design for worse case headroom at 200V only to find in the
UK, we are (still) using 240V and dissipating heaps.

Regards,

Tony Allgood  Penrith, Cumbria, England

Oakley Modular Synth and TB3030:
www.techrepairs.freeserve.co.uk/projects.htm
My music: www.mp3.com/taklamakan