[sdiy] SBM - Recommend Panel Pots & Knobs? Is a 'fake' Scope Risky?

[harry]

RE: Fake Scope...

Risky... only if you believe it when (and if) it lies to you. If you keep some
known waveforms handy  (maybe a low voltage transformer so you can use
the 60Hz sine wave for a sanity check...

Also... watch out for loading the circuits with the audio card input. You might
build a buffer amp for the front end  (like a TL071 perhaps?)  and maybe even
connect some switched attenuator at the output. And get a real scope probe for
$20-30 bucks... preferrably a 10X (attenuating) probe. This will load circuirs a

lot less.

Then AC coupling only becomes an issue.  Soon a "real" scope will serve you
better... but till then go for it the way you are...its way better than just
using
a meter alone.

H^) harry

vitreousflux wrote:

> Thanks to all who replied to my questions!
>
> These links helped a lot, I printed that guide out today and studied it
> closely. I think I can do that project without too much trouble - the fact
> that each module is wired separately will help. Adding a few small
> additional protoboards on top for the additional modules I want shouldnt be
> too much trouble.
>
> Panel Design: I think hi-res color inkjet with a laminate should be ok, if
> adhered properly (and if it avoids sunlight). Any thoughts on this? How
> about sources for panel material (aluminum?)
>
> Pots and Knobs: I really like the quality pots on my Mackie mixers, so I
> called them for pricing on parts. 79 cents and 1.59 each, depending on the
> pot. How does that compare to pricing of other quality pots & knobs that
> people have used?
>
> Fake Scope: I don't have a 'real' oscilloscope anymore, but I have a
> roundabout/poor man's version that has worked in the past (being very very
> careful of course). It is limited, in that I can only measure signals that
> are within a line-level audio input. What I do is first check the signal
> with a meter to see if it's within what I can connect to my mixer, then I
> route that into my computer with an oscilloscope program - it has a pretty
> accurate measurement if I calibrate the mixer gain first. Am I a complete
> idiot for even attempting this? It has worked for me in the past, especially
> for calibrating waveshapes and such.
>
> Modding my old MiniKorg has been a good break-in project, as it is almost
> entirely discrete components. In designing what/how to modify it, I dragged
> out my old EET books and cleaned the rust off my schooling. Now I'm
> refreshed and ready to dive into a bigger project. (if you want to see
> pictures of the modded MiniKorg, visit my web page at
> http://zap.to/vitreousflux and click on the synths link.)
>
> I'll post some images of my finished panel pics to my web page if people
> want to see it.
>
> Thanks again, guys - I'll check the EFM list too.
>
> Rob
>
> ----- Original Message -----
> From: "tomg at efm" <efm3 at mediaone.net>
> To: "vitreousflux" <vitreousflux at wwnet.net>; "Synth DIY Maillist"
> <synth-diy at node12b53.a2000.nl>
> Sent: Tuesday, February 27, 2001 12:00 AM
> Subject: Re: [sdiy] Anyone built a EFM SBM?
>
> > > Hmm well, I'm not really a newbie to electronics and soldering. Also I
> > have
> > > much experience using the PC softsynths, designing modular synths from
> the
> > > ground up - some of them very complex. This is where the DIY project
> comes
> > > in, as I would like to break into hardware now that I've "gone modular
> and
> > > can't go back"....
> >
> > We understand. It's ok,  you're among friends here. I should warn you that
> > full blown addiction is quite fast and unexpected....before you know it
> > you'll be
> > shopping for frequency counters and oscilloscopes...;-)
> >
> > > The Fatman was one I was considering but it really seems sonically
> limited
> > > for what I want. Viewing the ASM-1 and SBM PCB's, that should be ok (yet
> > > still a large project) for my soldering skills.
> >
> > Ok.
> >
> > > Ummm well the TB303 sound is not really of much interest/usefulness to
> me,
> > I
> > > mostly use 1 and 2+ osc synths with a lot of slow, flowing filter
> > modulation
> > > and such, customizing is the key. The main idea I have for adding a
> > modular
> > > synth to my studio is the flexibility, control and integration with
> > existing
> > > gear.
> >
> > The BassAce is 1 VCO w/sub-oct generator but the 303C is 1 VCO lean, mean
> > and much more useful than you might think. A didicated midied analog bass
> > synth that you never have to patch is a killer thing to have for bass
> parts.
> > Modulars
> > tend to be mono or occupied doing other things.
> >
> > You'll understand when you see/hear it later this/next week. Maybe
> not...You
> > have to face a pile of  patch cords for a while before normailzed stuff
> > starts
> > looking like a great idea!!
> >
> > > Probably the only thing I don't want to jump headlong into is etching my
> > own
> > > PCB's. I have no problem adding small protoboards if I decide to mod or
> > > change the modular (again, provided I go the route of designing the
> panel
> > > myself)
> >
> > Here's something to think about. I uploaded a 2r normalized idea today.
> How
> > much SBM can you get on a 2r panel?
> > http://groups.yahoo.com/group/EFM_Synth/files/SBM/sbm2r.gif
> >
> > And here is the assembly manual to look over. If you're game so are
> we...;-)
> > http://groups.yahoo.com/group/EFM_Synth/files/SBM/sbm-assembly-manual.pdf
> >
> > You might have to join the EFM list to get these files.
> >
> > Tom
> >
> >