[sdiy] More on the AN299 VCO

[flightofharmony at comcast.net]

Which is why it didn't work well the first time around!

This time, I assumed that Q6 in the App Note would correspond to Q5 in the array. So far, it's been pretty stable: after one hour running in open air it has only shifted by ~1.5Hz. I'm assuming proper thermal insulation in a closed box would cure that.

The remaining problem is the max. frequency is around 1950 Hz, then it latches until the CV is lowered. I had this problem the first time as well, any ideas? BTW - I'm using a TL082.


 -------------- Original message ----------------------
From: Ian Fritz <ijfritz at comcast.net>
> At 09:51 AM 4/30/2008, Neil Johnson wrote:
> 
> 
> >Apologies if this has already been discussed, but it seems to me that you 
> >have IC2A the wrong way round when compared to the schematic in AN-299.
> 
> 
> AN299 does not specify which transistor in the schematic is which in the array!
> 
> You can easily see this by the fact that Q6 is part of the array, which, of 
> course, only has five transistors.
> 
> Ian  
>