[sdiy] Two more questions

sbernardi at attbi.com sbernardi at attbi.com
Tue Aug 6 21:51:30 CEST 2002


Here's a 78xx, 79xx regulator based design:
http://home.attbi.com/~sbernardi/elec/og2/og2_powersupply
.html
Also take a look on eBay - they often have linear triple 
supplies (don't buy switchers) for cheap. 

As for PCB's, a lot of people have different preferences 
for what they like to do.  Certainly if you were going 
to go in quantity, I would have them done 
professionally.  In all the synth building I've done, 
however, I don't believe I have more than two of one 
kind of board (well, maybe some VCA's). I'm always 
trying new designs.  At about $66 for two boards 
(cheapest rate I've seen), that is more than I like to 
pay. So I make my own. Now my boards aren't very 
complicated, (not like the gargantuan PCB's that Jim 
Patchell designs), and I used fairly wide traces (30 
mil).
I use the photo-etch process. Print the pattern on 
transparency with a laser printer with fresh toner (con: 
sometimes I still need to touch it up with a marker). I 
buy presensitized PCB's from Circuit Specialists 
http://www.web-tronics.com/, which I expose with a 
flourescent light for about 10 minutes a side.  I etch 
them in a etchant tank with Ammonium Persulfate (both of 
which I also got from Circuit Specialists). Then I use 
Tinit to plate the traces. Then drill, drill, drill.
It is a lot of extra work. I guess I'm weird - it's one 
of the parts of synth building that I enjoy doing. 
> I've got a couple more questions :)
> 
> First, I'm having trouble finding a schematic for either a 15 volt bipolar power 
> supply, and/or a +5 volt, does anybody know of a good design they could point me 
> towards?  
> 
> My other question is; when you are finished a design and are putting it on a 
> pcb, do you use vero, etching, or photo-etching? (sorry if those aren't the 
> proper names).
> 
> I made a circuit a long time ago from an old magazine, I used a permanent marker 
> on copper and then etched it, but I don't have a steady hand and it was sloppy, 
> some parts were thin, some were thick, etc.  The etching where you use light 
> sensitive chemicals seems to be way too much work but maybe it's easier than it 
> sounds.  I've also seen rub-on decals which I'm guessing are used instead of a 
> marker.  
> 
> Vero board looks like it could get sloppy in inexperienced hands.
> 
> So I'm just wondering, is this a matter of preference, or is there really only 
> one good way to do it?  
> 
> 
> > Steve Begin
> > 
> > 
> > 



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