[sdiy] Power supply for Big Briar Etherwave Theremin

[Roman Sowa]

Exactly, it must be "grounded" in a sense of "earthed", and not 
"center-tap".
If you connect center-tap transformer there, it will not be grounded, it 
will be floating. And also it will be very hot, because ground pin on 
the socket is shorthed to one of AC pins.

You need a link from earth protect prong in your AC outlet to one end of 
your supply.
It all becomes so clear when you look at power input schematics on page 4

Do what Gordon says

Roman

W dniu 2022-07-06 o 08:05, Peter Pearson via Synth-diy pisze:
> https://manuals.fdiskc.com/flat/BigBriar%20Etherwave%20Service%20Manual.pdf 
> <https://manuals.fdiskc.com/flat/BigBriar%20Etherwave%20Service%20Manual.pdf>
> 
> Read page 8 of the service manual where it says - and I'm quoting here - 
> "*WHY IS THE POWER ADAPTER GROUNDED?*"
> 
> On Tue, Jul 5, 2022 at 7:04 AM Gordonjcp <gordonjcp at gjcp.net 
> <mailto:gordonjcp at gjcp.net>> wrote:
> 
>     On Thu, Jun 30, 2022 at 02:41:07PM -0400, Peter Pearson via
>     Synth-diy wrote:
>      >
>     https://manuals.fdiskc.com/flat/BigBriar%20Etherwave%20Service%20Manual.pdf
>     <https://manuals.fdiskc.com/flat/BigBriar%20Etherwave%20Service%20Manual.pdf>
>      >
>      > The schematic is here.  A DC supply won't work.  The theremin
>     might be
>      > fussy about grounding though, so you'll definitely want a
>     center-tap on
>      > your power adapter.  I wouldn't recommend trying to cheat a
>     barrel jack AC
>      > power adapter in there.
> 
>     If you look at the power input circuit, there are only two
>     connections.  There's nowhere for a centre-tap to go.
> 
>     It's a simple transformer fed into a pair of half-wave rectifiers,
>     same as the various crappy modular PSUs that are kicking around.
> 
>     Everyone is making this waaaaaaaaaaaaaaaaaaaaaaaaaaaaaay more
>     complicated than it needs to be.
> 
>     A 15V transformer will be fine.  It doesn't need a centre tap. 
>     Anything over 200mA will be fine.
> 
>     -- 
>     Gordonjcp
> 
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