[sdiy] newbee! help!

[Scott Gravenhorst]

Assuming that the configuration is really as Scott
has shown in the ASCIImatic below, it may also 
depend on the values chosen.  If the cutoff 
frequency is really really far from the signal
frequency, one filter will pass the signal, while
the other will see it in the stopband.  It may
be that "doesn't work" really means "attenuated so 
much I can't hear it."

Scott Bernardi <sbernardi at attbi.com> wrote:
>The simple RC filters should be connected like a "voltage divider" (in series), not
>in parallel.
>Don't know if this ASCII circuit diagram will come out right:
>
>Low Pass:
>
> Vin o---/\/\/\/\/\-----------o   Vout
>                              |
>                              |
>                         -----+-----
>                         -----+-----
>                              |
>                              |
>                           ---+----
>                            -----
>                             ---
>
>High Pass:
>
>                      | |
>                      | |
>   Vin o -------------+ +-------o   Vout
>                      | |       |
>                      | |       <
>                                >
>                                <
>                                >
>                                |
>                            ----+----
>                             -------
>                               ---
>
>As for the breadboarding, the Radio Shack types work fine.  What are you using for
>power supplies? Opamps need power, usually split (+ and -) supplies.  A couple of
>9v batteries will work if that's all you have. Make sure you get the polarities
>right!
>
>
>
>the-h at mail.utexas.edu wrote:
>
>> Hiya synth diyers. I am just starting up with synth diy and have been testing a
>> few things on breadboard and am getting some strange results. I first made a
>> simple passive high pass filter just a capacitor with a resistor across it. It
>> worked fine but then i switched the capacitor and resistor (to make it low
>> pass) and it just stopped working, no sound at all. Ive also been trying to do
>> some simple stuff (making an inverter or regular amp) with an op amp. and
>> meeting with unbrideled failure, they just don't work. I think my main problem
>> might be my technique for connecting the 1/4" jacks into the breadboard, or my
>> laying out of components on the breadboard. If someone could recommend some
>> construction and prototyping techniques it would help a whole lot. I have one
>> of those minimal type breadboards, no power or oscilator or nothin (its the
>> kind you can get at radio shack). Any help would be great.
>
>--
>Scott Bernardi
>sbernardi at attbi.com
>
>
>

=========================================================  
- Government: The other religion.
- The media's credibility should always be questioned.
- Lambs who lie down with lions are lunch.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.GTE.NET/res0658s/TekLab_FatMan_WebSite/index.html