On mine, I had different issues, but like this user, at first my synthacon
didn't work. I ended up fixing things by checking each resistor value
with a DVM. I didn't have a value wrong, but, I did find a short (no
resistance, where there should have been some). Correcting this--it was a
solder blob-- fixed my filter, and it's worked ever since.
Just visually inspecting my solder joints, component placement, and what
not has never been that helpful for me solving whatever is wrong with my
build, unless it's something really obvious, like putting an IC or diode
in backwards. I always do a visual inspection, and I usually catch those
really major foul-ups before I power up the board for the first time.
But I never catch them all! For anything subtle, I tend to miss the same
mistake over and over unless I use a scope and/or DVM to troubleshoot.
--CL
didn't work. I ended up fixing things by checking each resistor value
with a DVM. I didn't have a value wrong, but, I did find a short (no
resistance, where there should have been some). Correcting this--it was a
solder blob-- fixed my filter, and it's worked ever since.
Just visually inspecting my solder joints, component placement, and what
not has never been that helpful for me solving whatever is wrong with my
build, unless it's something really obvious, like putting an IC or diode
in backwards. I always do a visual inspection, and I usually catch those
really major foul-ups before I power up the board for the first time.
But I never catch them all! For anything subtle, I tend to miss the same
mistake over and over unless I use a scope and/or DVM to troubleshoot.
--CL
On Wed, 2 Jun 2004, earthtodylan2000 wrote:
> Ken,
> I've gone over the whole board all the whole board and it look
> alright.
>
> 1. I am only getting this very wrong and noisy signal when I put
> something through the Hi Pass filter and nothing when running
> through the Band and Lo pass inputs
>
> 2. I have used the exact transistors(metal can 2N2907, 2N222A)
> you call for. Everything else too is from you exact specs.
>
> 3. Fair enough...I'm sure this will work out once it becomes clear
> how to correctly wire things up.
>
> 4. This is the confusing part. How was I supposed to know the
> frequency pot is wired with its CW end to+15, its CCW end to
> ground/0V and its wiper to one of the CV inputs? Schematics?
> And where is +15 on the board? Is it just one of the +
> openings?
>
> 5. I have a link instead of the pot.
>
>
>
> How simple would it be to have a little diagram that show how to
> wire this thing up like on some of your other PCB pages?
>
> I'm still not so sure that It's going to work after I make these
> changes.
>
> Wire +15(or the + opening)to the Frequency pot.
>
> What are all the other openings for and what goes to them?
>
> The other "+"
>
> "-"
> "+VE"
> "+6V"
> "-VE"
>
> And are all the pots sopposed to get some sort of voltage?
>
> Thanks,
>
> Dave
>
>
>
> --- In cgs_synth@yahoogroups.com, sasami@h... wrote:
> >
> > > I just tried to build up my Synthacon. Total nightmare...
>
>
>
> > I'd suggest you go very carefully over the board looking for
> construction
> > errors. If you have not used the exact transistors specified,
> make sure they
> > are in the correct way around. of the very few that haven't
> worked, it has
> > almost always been a construction error. Once or twice it was
> a faulty
> > transistor.
> >
> > >1. Only getting sound out of the Hi Pass input
> >
> > out of? do you mean that you only get an output when you feed
> the signal
> > INTO the HP input and not when you feed a signal into either
> the band pass
> > or low pass inputs?
> >
> > >2. The sound is super fuzzy with lots of harmonics.
> >
> > If the resonance is too high it can distort some, but I would not
> call it a
> > fuzz box. If you have used the wrong transistors, you may have
> way too much
> > gain. I specified metal can 2N2222 (or 2N222A) and 2N2907
> for a reason.
> >
> > >3. Ground hum.
> >
> > Now that you can only blame yourself for. Wither you have an
> earth loop
> > somewhere in your system, or you have a poorly sheilded input
> somewhere that
> > is picking up hum.
> >
> > >4. Pots dont' seem to control anything.
> >
> > If wired correctly, they will. Is the frequency pot wired with its
> CW end to
> > +15, its CCW end to ground/0V and its wiper to one of the CV
> inputs?
> >
> > The resonance pit needs only two wires - one the the wiper,
> and one to one
> > end. The other end is left not connected to anything at all.
> >
> > >5. My Binary Zone does seem to control the CV frequency
> input.
> >
> > which would indicate there is at least some voltage control -
> ans if your
> > pots aren't doing anything, that means at the very least, the
> frequency pot
> > is incorrectly wired.
> >
> > >Does someone have a wiring diagram?
> >
> > All the wiring info is in the circuit diagram itself. That should be
> all you
> > need.
> >
> > >I did ground all the 1/8 inputs together.
> >
> > Yes, the sleeve of all jacks need to be grounded.
> >
> > >I first tried it with the Level pot and then took it out of the circut.
> >
> > Do you have a link in place or the level pot instead?
> >
>
> __________________________________________________
> _____________________
> > Ken Stone sasami@h... or sasami@c...
> > Modular Synth PCBs for sale
> <http://www.blaze.net.au/~sasami/synth/>
> > Australian Miniature Horses & Ponies
> <http://www.blaze.net.au/~sasami/>
>
>
>
>
> See the following URLS for the CGS Modular Synth home page:
> Main: http://www.cgs.synth.net/
> Secondary: http://otherunicorn.0catch.com/synth/
> Yahoo! Groups Links
>
>
>
>
>