Dave Smith Instruments SYNTHESIZERS

I'm going to stick my neck out here and say the concentric plug style that
the evolver uses is fine to unplug, without causing any shorting problems
in-and-of iteslf.

Pull it out, and look at the black insulation between the inside and the
outside of the barrel. nothing's going to get shorted to the wrong thing
here. The only really bad design for power supply connectors is those 1/8"
jacks used on some PSU pedals... because its possible to short sleeve and
tip of the plug together on the sleeve part of the jack when pluggihng or
unplugging a live connector. Still, this will only blow the power supply,
not the equipment itself... .

Obviously there is some instability in the PIC firmware that allows it to
unprotect itself and write over itself in the wrong situation, but since
this is an intermittent thing (affecting what? 5 to 10 evolvers in total so
far? and many of these fried during updating, but some just fried during
normal use!!!) it'd be hard to track down. perhaps it's not even *all* the
fault of the firmware? maybe a case of power spikes getting into the EVO
from the power lines at a certain time? Or maybe just a case of the power up
reset chip moving too slow??

BTW, often the wallwart isn't the only thing storing charge. Any synth will
have capacitors in it, for smoothing out the power supply rails and
decoupling AC out of them at all the different parts of the circuit...

oh, and if you *really* want a power switch for your evolver, get a simple
inline one installed near the end of the power plug! it's be a $2 part, and
about 5 minutes work for someone who knows what they're doing.


Julian


----- Original Message -----
From: graeme
To: DSI_Evolver@yahoogroups.com
Sent: Friday, October 31, 2003 11:05 PM
Subject: [Evolver] Evo Killing


Just a general point re un/pluging units , IMO i find it a def *No No* to
directly unjack a PSU supply from the body of a synth/module, as metioned,
an unintentional short can wreak havoc with the gubbins.
I would strongly recomend getting some power boards with individual switches
so wall warts can be individually isolated.
Its worth noting too that most WW's carry a residual capacitance charge even
after they have been unplugged (note how slowly the power LED "dims" on some
WW units) so even when the "wart" end of a WW is unplugged it is still
capable of discharge via the instrument end.

OTOH, a simple Evo on/off mains switch would save me from grovelling on the
floor every time i need to power down the wee blue beasite and solve an
unintentional shorting.
;o)