[sdiy] L(cheapo)FO

[Michael Ruberto]

Harry, of course I'm interested :)

M. A. Ruberto

>From: harrybissell <harrybissell at prodigy.net>
>To: Michael Ruberto <frankentron at hotmail.com>
>CC: synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] L(cheapo)FO
>Date: Sun, 26 Jun 2005 18:07:13 -0400
>
>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
> > >
>