[sdiy] L(cheapo)FO

[harrybissell]

Hello Michael

I think you could easily configure this as a voltage controlled LFO ???

interested ???   :^P

H^) harry

Michael Ruberto wrote:

> >
> >So why did you draw the schematic with the non-inverting inputs
> >on the top ???   :^P
> >
>
> yeah I know! the model for the LM324 was drawn that way and I was too lazy
> to make a custom model for it. On the breadboard I have a 200 Ohm resistor
> between the top of R19 and pin 14 on the 324. It's only there because I ran
> out of jumpers so I didn't include it in the schematic. I doubt it has any
> real effect on the range.
>
> >well if that is my only complaint, it looks pretty good to me !
> >I wondered about the LEDs till I saw the 5V / 10V note. OK !!!
> >
> >Is the sawtooth 2X the frequency of the triangle ???
>
> Saw output is the same rate as triangle.
>
> >
> >How good is the sine output (looks good, sounds good ???)
> >
>
> I cannot view the waves but the ear-oscope says yeah! triangle sounds
> perfect to me and the sine sounds like sine but kinda fuzzy like overdrive.
> I guess there must be a glitch in the waveshape but it isn't objectionable.
> After I solder this up on some perf board I'll bring it over to the computer
> and record the waves. Then I can view them in Sound Forge...
> I must say the saw sounds very nice and rude, it's got balls.
>
> M. A. Ruberto
> >
> >Michael Ruberto wrote:
> >
> > > Got in some breadboard time today. Since both of my previous synths
> >started
> > > out with an LFO I felt my new one should too. My design goal was to make
> >it
> > > as cheap as possible and use only the small supply of parts I had on
> >hand.
> > > Unfortunately, I had to desolder many of the resistors from scrap PCBs
> >to
> > > avoid running to Radio Shack.
> > > Anyway, this design works pretty good and has decent range and features
> > > considering the small parts count - just 1 IC and 2 transistors. The
> >outputs
> > > are sine, triangle, square, and saw up or down. I get roughly 7V peak to
> > > peak from the triangle and saw outputs, 6 volts peak to peak from the
> >sine
> > > output and +5V from the square.
> > >
> > > http://frankentron.freezope.org/source/diy_blue/images/LFO1_rev1.gif
> > >
> > > Enjoy!
> > >
> > > M. A. Ruberto
> >