+ - 15 volt supply

[jhaible]

> Although I will agree that linear supplies are better suited for our
> particular application, it should be noted that many of today's
top-quality
> professional synthesizers have switching power supplies.  For instance,
the
> Yamaha TX-816, the DX7-II, the Roland XP-80, most Akai samplers, and many
> others.  I have used these instruments in many studios and have never had
> problems with noise (OK... the TX-816 was a little hissy, but that was
12-bit
> FM hash, not power supply noise!)

None of these boxes has VCOs. I wonder if there would be a soft sync
effect between VCOs and switching PSUs. Mind you, I don't really know
because i've never tried, but when VCO -> VCO soft sync over the supply
rails can be a problem in ordinary synths, there might be reason to fear
that all your precious VCOs get soft synced to a switcher frequency.
Remember the Minimoog trick to avoid unwanted soft sync ? Noisy
power supplies. Now imagine a noise that is not random anymore, but
the power supply rails polluted with 100k switcher frequency ...

JH.