[sdiy] Eurorack Power Protection

[matt holland]

I'm not a euro mfg so take this all with grain of salt.

On Tue, Jan 3, 2017 at 2:35 PM, Jacob Watters <jacobwatters at gmail.com>
wrote:

> Thanks for all of the feedback so far. Here are my notes:
>
> Boxed Header
> This is what I plan to use. Maybe my pin umbers are off. I was going by
> the image linked below. Is pin 1 on the bottom right in this image?
>
> http://www.doepfer.de/a100_man/a100b_e.gif
>

pin1 is not labeled in that image. this gets to the heart of all the red
stripe problems.


>
>
> Diode
> It seems like I should just not use it?
>

diodes are always a good idea where it's possible to connect power
incorrectly.


>
> Resistor
> Don't use it?
>

It doesn't hurt anything, and it's nice to have series elements on power
inputs to experiment with in case you determine filtering is needed, or for
current measurements.


>
> Ferrite Bead
> Some people are telling me outside this list that ferrite is more for
> digital stuff and that the capacitor should be fine. If I don't use the
> ferrite then should I use a resistor instead?
>

If you determine you need a ferrite, you can put it in the spot that
resistor above was using, otherwise don't worry about it.



>
> Capacitors
> Only use the larger one (I use a 0.1uF bypass cap at each IC anyway). Some
> say increase and some say decrease. In non-modular stuff I usually use
> larger ones, so I am leaning towards 22uF.
>

Caps at power entry are "bulk" caps and their value isn't critical as long
as they are large. What is "large" would be relative to the inductance seen
on the ribbon cable, bus board, etc and the instantaneous current draw of
the module as a whole,  but would probably be something like 10uF or 22uF
or higher.



>
>
> I wish that there was a standard for this so I knew what to do :(
>

No standard required. Just pick a reasonable worst case scenario and
design/test to that (easier said than done I know).

mh


>
>
> On Tue, Jan 3, 2017 at 4:52 PM, Andre Majorel <aym-htnys at teaser.fr> wrote:
>
>> On 2017-01-03 12:56 -0800, Tim Ressel wrote:
>>
>> > I found a 22uF bulk cap is the minimum for noise reduction.
>> > Remember the rails in Eurorack case can be noisy. 10 ohms is
>> > okay for a module that pulls little current. I use 1 ohm.
>>
>> Some years ago, Tony Allgood mentioned that he had to switch
>> from 22 to 2.2 µF per rail because the surge current from lots
>> of 22 µF capacitors in parallel made certain Power-one supplies
>> misbehave on power-up. But that was with ferrite beads, not
>> resistors.
>>
>> --
>> André Majorel http://www.teaser.fr/~amajorel/
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20170103/7ef891c0/attachment.htm>