Doing it all in 4069s (Was: Re: [sdiy] New Vco (new images))

[tomg@efm]

What Magnus wants to do is use inverters to build opamps 
and replace the 072 still using  the dual npn.  Both of the 
opamps used are inverters. You might have to run a separate 
4069 on a split supply of some sort or maybe use a split 
supply for the whole thing....but maybe......It should be 
possible... 

Of course it's not really necessary...Rene did it without any 
opamps at all...Using something like that Tau vco Jim posted
as an example you can build a discreet current sink. Then
all you need is a discreet mixer......you can eliminate opamps
and inverters.  

Tom


> Rene's original design did this, tom put the 072 in there.
> 
> > Magnus Danielson wrote:
> > 
> > >
> > > Hmm interesting!
> > >
> > > This kind of rings a bell in me, I've actually considered the oddball
> > > idea of building a synthesizer with 4069s as the only active
> > > component.
> > >
> > > A 4069 is basically a high gain inverting amplifier. If you look at
> > > the above VCO, you should be able to remove the TL072 by using two
> > > more of the 4069s inverters. Just think of it, it is indeed possible
> > > even if it requires some more thougth.
> > >
> 
>