[sdiy] Re: P5

[harrybissell]

My (long gone) P5 tuned with the pot at 12:00 high.

I'd check the voltage of the wiper with the pot centered.

H^) harry

Oakley Sound wrote:

> Hi Harry,
>
> Many thanks for your reply.
>
> > I just put a bigger heatsink on my P5 ...
>
> Oddly enough I never thought about that, I guess I was looking for a more
> refined solution to the problem :-)
>
> The rev 3 heatsink is quite sizable really and miles better than the rev
> 2 which has nothing of course. But you're right a bigger one will
> certainly help get it cooler.
>
> In theory it should be easier than putting a second transformer into the
> unit.
>
> Incidentally, does your Prophet 5 tune up correctly with the tune pot in
> the middle position? Mine tunes up so that the pot always has to be set
> at around 10 o'clock to get A440. The internal A440 is indeed 440Hz, and
> keyboard tracks wonderfully. The circuit that disables the tune and pitch
> bend pots is working correctly, ie. its output doesn't change when the
> tune routine is initiated with the pitch bend and tune pots are set in
> their middle positions.
>
> Beats me how mine is offset in this way. Surely, if the only common
> things to all VCOs are apparently negated I can't see why its auto-tune
> doesn't pull all the VCOs in correctly. Its like something common to all
> the VCOs is acting on them once the auto-tune routine is finished.
>
> Many thanks,
>
> Tony