In article , Peter Chant
wrote:
Jim Lesurf wrote:



And the AU-D3 seems to be designed for 5V rail. So a PP9 would be
risky due to the higher voltage. FWIW I've asked the makers for more
info on the AU-D3 so may know more later. If so, I'll report anything
useful.

You could stick a voltage regulator in there for the DAC.

Yes. But for the prototype that would have added components/complications,
and in my experience the 'one chip' regulators tend to cause problems -
more details required to then prevent that. And it would be wasteful to
drop 9V to 5V when 4 x AA NiMH gives about 5V anyway.

Used the HeadDAC this afternoon to listen to a DVD I made of last nught's
AYO Prom. Another hour and the batteries still seem fine on their first
charge. The PSU that came with the AU-D3 says "0.3 to 0.5A" for its dc
output so I'd wondered if the AU-D3 was current hungry. The AAs I'm using
are rated as 1700mAh which implies from that somewhere in the 3 to 6 hour
range between recharges. Not been keeping notes, but I'd think I'm now well
over 3 hours of use.

For split rails from one set of cells it occurred to me that the trick QUAD
used for the PSU in their 34 preamp might avoid switchon thumps/clicks.
That uses an op-amp to center the ground about the polarities of a single
psu potential difference. Means 'both rails come on together' as soon as
that op amp wakes up. :-)

Slainte,

Jim

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