I totally understand the concerns with publishing the raw numbers, because there's always more to it than that. I was hoping there may be a 'worst case scenario' figure for some of them - obviously the more supplies, the better the results, however I'm sure there must be an 'overkill' point as well - I can't imagine there's any sense in dedicating an entire Blacet PS500 for every Wiard module!
I will probably make up a little test rig so I can get a rough idea how much I'm pulling from my supplies - or just use the VCO trick!
One last question - is the fact that the PS500's power inlet ground lug is NOT wired up a concern for the 'built-in' star grounding the Wiard 300 modules employ? The way these PSU's ship there is no path to earth ground through them.
Thanks again everyone!
Best wishes,
Mike
From: "Grant Richter" <grichter@asapnet.net>
Date: Sun, 19 Oct 2008 18:26:24 -0000
To: <wiardgroup@yahoogroups.com>
Subject: [wiardgroup] Re: Power supply question
This discussion has occurred many times in the past.
If you look in past discussions, they will detail the legal and technical problems with
publishing that kind of specification.
Put simply there are many measurements of current, peak, average, RMS.
The only way to be safe legally is to use NIST traceable instruments and that service is very
expensive.
The method I recommend doesn't need any math, and is more practical. Connect a VCO
first to the power supply, then add modules until the VCO starts to become unstable and
remove one.
VCO stability is the first thing to be affected when the power supply is overloaded.
Wiard VCOs normally show stability of +/- 1 cent. As the supply gets overloaded, they will
start to wander +/- 3 cents or worse. This is you best indicator, and the most important
parameter in the system (to some people).
Other put Variacs on the supplies and reduce voltage to deliberately destabilize oscillators
and make the whole system behave chaoticly, to my knowledge, this does no harm and is
a kind of circuit bending without opening the covers.
The creative techniques this group originates continues to blow my mind.
--- In wiardgroup@yahoogroups.com, "Muff" <muff@...> wrote:
>
> Good to know, thanks!
>
> It would be great if Grant or someone could provide some specs on each module
estimating the amount of current they use. I know these aren't always absolute numbers
though, perhaps that is part of the concern with posting them.
>
> -----Original Message-----
> From: atonal <atonal@...>
>
> Date: Sun, 12 Oct 2008 12:50:37
> To: <wiardgroup@yahoogroups.com>
> Subject: Re: [wiardgroup] Re: Power supply question
>
>
>
> My six module system is nearly the same configuration as yours, with the
> exception that I have a Waveform City instead of a Classic VCO. As I
> mentioned in my earlier post to Tommy, Grant measured the draw on my
> system to be 475 mA with all LED's illuminated. I would imagine that
> your system will be in that general vicinity, which would mean that one
> PS500 will be pretty close to capacity, with perhaps a bit of headroom.
> Grant also measured the draw on my New Controller to be 125 mA, which
> is why he recommended a second power supply for maximum stability.
>
>
>
> muffwiggler wrote:
> > Speaking of current draw, a couple of questions...
> >
> > I've got a 6 module system on order with Grant which I'm expecting in
> > a few months. I have some unused Blacet PS500's that I'm planning to
> > use, but I'm wondering if anyone has measured or knows the current
> > draw of the various 300 series modules. I have never come across
> > this information anywhere, and I'd like to know if I can power my 6
> > module rack (VCO, Wogglebug, Sequantizer, Borg I, Envelator,
> > Mixolator) from one PS500.
> >
> > I believe that Grant once said the 1200 Series JAGs pulled about
> > 100ma each, and the joystick no more than 20. So that would mean the
> > New Controller would be pulling something like 240ma - almost half
> > what a PS500 can manage. I assume that's a lot more than any single
> > 300 Series module.
> >
> > John Blacet told me the PS500 is very conservatively rated and one
> > can safely draw up to 550ma from it.
> >
> > A second question - it seems the PS500 doesn't have the ground prong
> > of its power inlet wired up. I have quite a few of these supplies
> > and they are all configured this way by Blacet. I know the 300
> > series has been designed to automatically provide star grounding, but
> > does it not compromise this when the path to ground through the power
> > inlet is not available?
> >
> > thanks everyone
>