[sdiy] Prebuilt bipolar 15v supply?

Fri Oct 12 15:23:50 CEST 2007

hi Kevin,

Thanks for the info. I probably should have been a bit more  
forthcoming with my plans, because I think you would have answered  
differently. Anyhow, here's a bit more in-depth explanation of what  
I'm planning to do....

Ray Wilson has kindly granted me permission to build and sell some of  
his modules commercially. I'm going to be offering them in Frac  
format in which case the power supply isn't a problem because that's  
up to the user. However, I realized that I could reach a wider  
audience if I also offered an optional wooden case for the sequencer  
where the wide (9 space!!) frac module could slide in and become the  
front panel. The only little hang up I'm faced with is providing a  
power supply. As I said in my original post, this is not something  
I'm comfortable building myself (at least not at the moment). So, I  
was hoping to find a pre-built supply, preferably a wall-wart sort of  
affair, because if the user has the option to open the case to put in  
or remove the sequencer for racking/unracking, I don't want high  
voltages floating around in there where some one could get hurt. Thus  
the appeal of a wall wart. The other really appealing thing is that  
the wall wart is pre built and all I would have to do is just buy  
them from Mouser, and I can get more of them as time goes on (hence  
my lack of interest in power supplies from Ebay). So... knowing the  
complete circumstances behind my question, what would anyone on the  
list recommend? Perhaps a wall wart with an voltage regulation system  
inside the case that would be completely low-voltage?

Regarding my blacet supplies, yes they are expensive, but the reason  
I went with them is that I had originally thought I'd need only 3 (ha  
ha) and that would power all the modules I'd ever have or want.  
(Funny how that works, isn't it?) So, they've just accumulated over  
time. I'm very pleased with them, however, and wouldn't consider  
selling them. Plus, given that my modular is bolted to the wall,  
whatever solution I go with has to be accessed strictly from the  
front of the unit, so implementing a system where I have a wiring  
harness would be difficult at best. It's just one of those things  
where at the present time, I know I could actually make money by  
selling off the Blacet supplies and buying one huge supply, but it's  
just not worth the time I'd have to spend to make it happen. Plus, I  
don't have any real worries about dirty power as the studio has a  
$50,000 power conditioning unit in the basement which (supposedly)  
keeps everything really clean electrically. I've never had an issue  
with a ground loop.

Thanks guys...

Sam E.

On Oct 12, 2007, at 2:46 AM, Kevin wrote:

> I should probably mention that if you are uncomfortable getting
> something like that used, Allied Electronics is their distributor.
> They cost quite a bit more new, but not so much compared to what you
> should be able to sell your 6 blacet power supplies for.
>
> https://www.alliedelec.com/default.asp
>
> On 10/12/07, Kevin <kevingeo at gmail.com> wrote:
>> Hi,
>>
>> You probably don't want a wall wart.  You want a regulated linear
>> supply where the output voltage is trimmable.  A lot of wall warts
>> like this will have voltages that fluctuate a lot.  It wouldn't be
>> unusual for 15v to really mean 17 or 19v.
>>
>> The specs say that supply regulates to +/-5%, which would be from
>> 14.25 to 15.75 volts.  If you use this power supply to power an
>> oscillator I suspect it will cause the pitch to drift.  If it goes
>> over 16 or 17 volts you may be into the range of possibly damaging
>> components on modules, so be careful.
>>
>> You might be interested in one of these two power supplies:
>>
>> http://cgi.ebay.com/ws/eBayISAPI.dll? 
>> ViewItem&rd=1&item=7596518741&ssPageName=STRK:MEWA:IT
>>
>> http://cgi.ebay.com/ws/eBayISAPI.dll? 
>> ViewItem&rd=1&item=7602669028&ssPageName=STRK:MEWA:IT
>>
>> I have the 5 amp version and am using it to power a bunch of Doepfer
>> modules.  It will output +/-15v or +/-12v.  I bought it from that  
>> same
>> ebay seller.
>>
>> You do have to wire an electrical plug to it, but that isn't
>> exceedingly difficult.  If you are uncomfortable doing that part
>> yourself you could probably find someone to do it for you.  The only
>> other thing you have to do is calibrate the output voltage with the
>> trimmers, which requires a voltmeter.
>>
>> This is basically the same power supply used by Cynthia/Cyndustries,
>> people use it for MOTM systems, and also the plan B space case uses a
>> similar supply from the same company.
>>
>> I have a link somewhere with someone showing how they wired their  
>> MOTM
>> system with this type of power supply if it would help you.
>>
>> Thanks,
>> Kevin
>>
>> On 10/11/07, Sam Ecoff <secoff at execpc.com> wrote:
>>> Hi All...
>>>
>>> Can anyone recommend a cost effective prebuilt power supply? I am
>>> aware of the Blacet PS 500 (great supply, already own 6 of them).  
>>> I'm
>>> planning to build Ray Wilson's 16 step sequencer (http://
>>> www.musicfromouterspace.com/analogsynth/SEQ16_2006/SEQ16_2006.php)
>>> and put it in a separate case.  Hence, another PS500 would really be
>>> overkill. I did a bit of searching, and came across this supply...
>>>
>>> http://tinyurl.com/yt67t9
>>>
>>> Seems like it would do everything I want it to do, but this is
>>> uncharted territory for me, so maybe there's something I'm  
>>> missing...
>>> The only problem I see with it is that it terminates in a five pin
>>> DIN plug, which means that at some point some student or an  
>>> intern is
>>> going to say "Oh... I found the other end of that MIDI cable!" and
>>> plug it into a MIDI jack on whichever piece of gear would cause the
>>> greatest catastrophe at the moment...
>>>
>>> I know that I could save a lot of money by building my own supply,
>>> but this is not something I'm currently comfortable doing. I don't
>>> feel that it is safely within my skill set, which means that it's
>>> probably best that I don't attempt it. ;-) I'm also aware that there
>>> are some prebuilt supplies that I could put in the enclosure, but to
>>> keep the unit as small as possible, I'd like to go with an external
>>> supply.
>>>
>>> Thanks in advance...
>>>
>>> Sam E.
>>> _______________________________
>>> Sam Ecoff
>>> Tanner/Monagle
>>> 1120 N. Market St.
>>> Milwaukee, WI 53202
>>> (414) 727-8190
>>> www.samecoff.com
>>
>