[sdiy] Thomas Henry's Potpourri Module questions

[Rykhaard D.A.M.I.A.N.]

On 12/31/05, Pete <23isgood at gmail.com> wrote:
>
>  Hi everybody. I'm building this circuit at the moment from Thomas Henry's
> old book, "Build a Better Synthesizer", and I wanted to learn how to use it.
> At the moment I got it on the breadboard and while testing, the Lag Time pot
> seems to do nothing. The lag is defiantly there but I wanted to know if I
> should change the pot to a different value?  Now I don't understand what the
> Buffer input on the Lag Processor is for?


Being on a breadboard, make absolutely sure of each connection listed on the
schematic, being exactly as it should be, on the breadboard. :O
Sorry if I'm stating this strongly, but I just destroyed a 20+ year old
breadboard of mine a couple of days ago, due to VERY bad contacts inside of
it.  Opening it up - sure enough, many of the pins were corroded. :(
Also - breadboards CAN be very fussy as to whether they're making the
contact or not. :(

The 1 meg value for the pot, is a very good value, for Portamento.  You
could use a 100k value as well, but you wouldn't be able to have, as long a
time for Portamento, as you would with a 1 meg pot.

The Buffer input in this schematic, is serving 2 potential functions.
- If you're inputing the signal straight to the buffer, then that signal
will be Buffered (exactly the same) at the output of the Buffer's opamp.
- If you're inputting the signal into the Lag input, the Buffer will act as
a buffer to hold the voltage as it grows, across the capacitor.  The pot, is
limiting how quickly that cap will charge up TO, the value that you are
feeding into it.  This is what gives you the slide UP or DOWN in the output
version from the buffer, of your input value. :)

Also what is a comparator and how is it used? I appreciate any help you guys
> could share. I uploaded a small archive with the pages from the book, check
> it out,


A Comparator will output either of 2 voltages:

- a HIGH voltage (almost to the power supply's + level of that opamp /
comparator chip)
- a LOW voltage (almost to the power supply's - level of that opamp /
comparator chip)

How this works.  The Comparator in this circuit, is set up so that you are
able to specify a Voltage Level, that you wish to be told, when it is
crossed, by your Comparator Input voltage.

You may specify this level either with the pot that is hooked up to the +
power supply or the - power supply, or the External Voltage (Threshold)
Input or both at once.

When your Comparator Voltage input is HIGHer than your Threshold, then the
Comparator will output a HIGH voltage.  When the Comparator Voltage input is
LOWer than your Threshold, then the Comparator will output a LOW voltage.

:)

I hope that helps you somewhat, at least. :)  Any other questions - fire
away. :D

<http://s19.yousendit.com/d.aspx?id=2HPG2VCS78I1C2751DLJ7JH2BF>thanks
> pete
>
> --


Nada trubba. :D

www.cubanpetemusic.com
>
>


--
Take care,
Warmth and Peace,
Ryk

http://deathlehem.bravehost.com/damian.html - D.A.M.I.A.N.;s webpage - Dec
2705 update
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