At 2:27 PM +0000 8/26/04, Rich Peet wrote:
>--- In "Rich Peet" <>
>wrote:
>> Well that is neat.
>> > http://www.uwm.edu/PSOA///Film/Danielson/Mic%
>> 20Preamps/AudioBuddy_PCBoard.jpg
>> > Hope you see something interesting, Best, Rob D.
>
>Looking at the photo more I don't understand why it will not work on
>dc. You just need to supply the correct polarity at 2.5 volts over
>the output of those regulators. The 4 digit number on the regulator
>chips will tell you the voltage out of them and just add 2.5 to 5.0
>volts. I also don't see that it would hurt it to supply the wrong
>polarity other than to make it not work.
>
>Are you sure you supplied the correct polarity when you tried it on
>dc?
With which power connection? For the most recent simple headed test,
I ran the postive to the center pen of the factory 10VAC connecter at
the back. I didn't think polarity would matter because it goes
through a rectifier doesn't it? Our mod, as below, worked.
>
>Looks like a simple full wave bridge conversion from ac to dc.
>filtered with just 2 large caps on both the + and - sides. then the
>outputs of that go to the two regulators.
Using Evert's suggestions, Bill tied in +/- 18 volts before the two
regs. it worked except for the CAD 179 phantom demands-- which was
the application I had in mind, M-S with NT1A and CAD-170.
>
>Rich
>
>Rich
--
Rob Danielson
Film Department
University of Wisconsin-Milwaukee
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