[sdiy] Thomas Henry XR-2206 VCO Page Up

[jays at aracnet.com]

Scott,

Have you tried a switch and a another timing cap to lower the freq?

Sort of a high/low freq switch like on some of the older VCOs. Might even get a LFO out of it.

You'd have to test to make sure the problem is with the linearity of the chip and not the freq it is operating at.

Jay S.

Scott Stites wrote:

> Thanks, Ian!  
> 
> Yes, that lower octave was the heartbreaker.  Tuning for perfect flatness down that low would shift things enough on the high end where the tracking just wasn't terribly good beyond five octaves.
> 
> I guess the main reason one would want to worry about the low end like that is that the ramp wave (from the skew) is double the frequency, so with the wave skewed to the octave up, it would still have the same amount of error.
> 
> Of course I think it's possible to get a ramp wave at the fundamental frequency, but that takes a bit more circuitry than Tom was willing to put in.  
> 
> Cheers,
> Scott
> 
>