[sdiy] synth power supply

[Derek Holzer]

Hi Kevin,

Thanks for the advice. I've had trouble with switching power supplies 
using laptops and soundcards before, so it makes sense that they would 
cause bigger troubles with synths. Because I travel to gigs with my 
synth quite a bit, I'm using a Doepfer "suitcase" currently. And so I 
would like to build another similar one. Keeping the PS "more than a 
foot" away from the modules isn't really an option here. Think: carry-on 
luggage ;-)

Then, is the best solution to build something around a ring transformer? 
  Or use the wallwart after all? I guess I'll be asking some 
electricians in Berlin for solutions.

best,
d.

Kevin wrote:
> The power supply you linked to on mouser.com is a switching power
> supply.  You don't want a switching supply for a modular synth - they
> are noisy.  You can see the doepfer yahoo group archives, about a
> month ago Dieter Doepfer tried out some switching power supplies and
> found them to be totally unsuitable.
> 
> You want a regulated linear DC power supply that has trimmable output
> voltages and is a dual +/- 12V supply (plus maybe +5v, if you care
> about the small set of modules that require it).  It should also have
> over voltage protection and a fuse.
> 
> I think any power supply like this you buy will require you to attach
> wires to the AC/DC transformer which then go to your power socket.
> The power socket will most likely be the place that has a fuse.  So
> you will be doing your own mains wiring.  You may want to consult an
> electrician or other qualified person to help with that to avoid any
> dangerous errors.
> 
> Another DIY doepfer case example (geared towards people in the US, sorry):
> 
> http://blue.netnation.com/~nop/diy/doepfer/
> 
> I used a power one power supply also.  I can dig up the model number
> if you want.  It does not use a toroidal transformer core like the
> doepfer PSU2.  However I keep it more than a foot from the modules.
> 
> On Nov 22, 2007 4:17 AM, Derek Holzer <derek at umatic.nl> wrote:
>> New thread for a slightly different question, related to how much EMI
>> can a power supply give.
>>
>> I'd like to build a new Doepfer case for less than the EUR 350 they
>> charge for a new one. And the DIY power supply kit they provide uses a
>> 15VAC 2.5A external wall wart which then gets rectified and regulated by
>> their DIY PS unit in the case, which I would like to avoid unless
>> necessary. I'd rather not mess with 220V myself, so I was looking at the
>> following power supply:
>>
>> http://tinyurl.com/2n3vmk
>>
>> (Sorry, German only...)
>>
>> Mouser:
>>
>> http://www.mouser.com/search/refine.aspx?Ntt=552-PSA-60-301
>>
>> But I have no idea how much EMI this might introduce into a small flight
>> case with modules mounted next to the PS. Doepfer use a very large ring
>> transformer which they say is quite clean. How would a PS like this
>> stack up against theirs?
>>
>> What other options would people recommend, keeping in mind that I don't
>> feel "qualified" to wire 220V?
>>
>> best,
>> Derek
>>
>> --
>> derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
>> ---Oblique Strategy # 84:
>> "How would you have done it?"
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
> 

-- 
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 111:
"Lowest common denominator check
-single beat
-single note
-single riff"