[sdiy] FETs for distortion

[Seb Francis]

Scott Gravenhorst wrote:

>>Do you mean 4049UB (actually it's not very obvious from the datasheets 
>>what the difference is between 4049 and 4069)?  This is another thing 
>>that I've been intending to try out (I've seen it used in a few 
>>distortion circuits, but until now I didn't think of it as a MOSFET).
>>    
>>
>
>Actually, I meant the 4069UB.  The difference is that the 4069UB has
>"symmetrical" MOSFETs, whereas the 4049UB does not.  I believe the 4049 will
>sink more current than it can source.  For a 4069UB, sink and source are
>equal.  To me, this fact makes the 4069UB more appropriate for this
>particular kind of thing.  However, if you are looking for asymmetrical
>distortion, then the 4049 is something worth trying.  In my circuit the
>clipping action of negative and positive peaks is essentially equal.
>
>
>
>  
>
Sounds like I will have to listen to them both!



René Schmitz wrote:

>
> The 4049s switching threshold is lower than the 4069s (which sit near 
> Ub/2). So its compatible with the lower TTL switching threshold.


I've also noticed (now I've got hold of comparable datasheets from the 
same manufacture) that ..

"The HEF4049B provides six inverting buffers with high current output 
capability suitable for driving TTL or high capacitive loads."

"The HEF4069UB is a general purpose hex inverter."


Seb