[sdiy] Overdriving 4069UB

[Scott Gravenhorst]

Very interesting, do you have a schematic up that you can share?

What sort of signal(s) did you test with?

Seb Francis <seb at burnit.co.uk> wrote:
>Well, I've been getting some really nice results with using between 1 
>and 3 stages of a 4069UB for distortion.  The MOSFET clipping has a 
>really warm sound to it.  (Incidently the 4049 really wasn't so good - 
>the clipping was way too asymmetrical.)  Anyway, more on this later .. 
>I'll publish the final circuit in due course.
>
>What I'm concerned about in my circuit design is whether it is safe to 
>drive the 4069 beyond its absolute maximum input voltage.  The quoted 
>absolute maximum range is -0.5V to VDD+0.5V (VDD=15 in my circuit).
>
>The input current is limited by a 10K resistor (with a DC blocking cap 
>in series before it), so although the opamp driving it can kick out up 
>to 28V ptp, the voltage at the 4069 input gets clipped to approx 17V 
>ptp.  This is a bit beyond the quoted absolute maximum, but I guess as 
>long as the current through the internal protection diodes is limited by 
>the 10K resistor then this is ok??  Is this a safe assumption?
>
>Seb
>
>

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