[sdiy] Cheap ccts....

[Jim Patchell]

    Well, I have good news and bad news.

    In general, the actual circuits are not all that expensive
themselves...this is the good news.  Depending on your skill level, you
probably want to select circuits that have the fewest number of components to
increase the odds you will get the circuit working with the minimal amount of
debugging (more compoents = longer debugging time squared).  Pretty much, any
circuit can be implemented with inexpensive parts.  The bad news is there are
a few exceptions.

    Off the top of my head, the two most expensive circuit components you will
run into are Matched Transistors and Tempco Resistors.  Premium matched
transistors come at a premium price ($7 US in some cases).  You can get around
this in several ways.  You can match your own transistors (buy a big bag of
2n3904's for cheap, and hand match the parts and glue them together with
epoxy).  You can also use some of the cheaper matched transistors, like the
CA3046.  Tempco resistors (the +3300ppM one) are not only difficult to find,
but also quite pricey when you do.  When building VCO's, you must have some
sort of temperature compensation for exponential oscilators to keep them in
tune.

    Now for some more bad news...Even if you can build the circuit for cheap,
you are going to have to do a bit of work getting the components for the front
panel.  The panel cost is a major component in the dent in your checking
account when building a synth.  You are going to need to search the surplus
houses to find pots and jacks at a reasonable price.  If you can't find decent
pots cheap surplus, you can get new pots from Mouser (http://www.mouser.com
).  They sell Xicon pots, and only cost about $1 each (about 80 cents if you
get them 100 at a time).  Knobs are another big problem.  Radio Shack used to
sell some really nice knobs are a good price, but have discontinued this
service (the only ones they have left are the ones they haven't sold yet).
Knobs can cost more than the pot does.  Which is pretty bizzare, if you ask
me.  You are also going to have to select the kind of Jacks you want to use
(which always sparks a debate here).  Keep in mind, you can get a lot more
cheap jacks for your dollar, but, you will end up paying for this with
frustration, but, you have-ta do what ya have-ta do.

    -Jim

Alan Podjursky wrote:

> What are the cheapest synth circuits (in terms of construction costs) that
> I could build, yet still get a halfway-decent sound from? (I have a local
> copy of TomG's Cookbook, if that's any help.) Being a student with little
> money majorly blows.