[TenTec] Switched audio filters

[Al Gulseth]

From what I've seen (these are all duals, there are also quad versions of 
most?) the NE5532 is noted for a good price/performance (low noise) ratio for 
an AF active filter. The LM833, TL072/82, and NJM2068 might also possibly be 
good candidates. Even the lowly LM358 might be usable with the caveat of 
adding a pull down resistor (drawing about 1 ma) to eliminate crossover 
distortion. (Info per ARRL's EMRFD p. 3.25.)

Disclaimer: as they say, YMMV....

73, Al
 
On Wed March 23 2016 12:03:01 pm Tim wrote:

> I copied the 208 filter as well, even etched the pc board. I wired it
> for the 515 and gave it to my Dad for Christmas one year. I have that
> filter, but I know the chip isn't made anymore. I would guess that an
> ordinary audio op amp would work. So yeah we can see what someone else
> might suggest.