Re: [softrock40] OP amp feedback capacitors.
- Thanks, Tony. I thought that might be the case. Glad to have it
On Wed, Jul 25, 2012, at 01:39 AM, Tony Parks wrote:
> Not critical Patrick. The assumption is that the RXTX will be used with
> a soundcard that can sample at a higher rate and thus having the LP
> break at a higher frequency makes sense. The 220pF capacitors will work
> just fine in the Lite II.
> Tony Parks
> On Wed, 2012-07-25 at 03:11 +0000, ac0sr wrote:
> > In the Ensemble Lite II the OP amps use 390pF caps in the feedback,
> > which would imply a low pass cutoff of about 80kHz, while the Ensemble
> > RXTX schematic that I have uses 220 pF caps implying a cutoff in the
> > neighborhood of 140 kHz. So is the value of the capacitor in this
> > application very critical, or are we talking "in the neighborhood"
> > values? I actually have a Combined Lite II kit that was given to me
> > that was missing the 390 caps, but had a pair of 220's instead. I'd
> > like to use them if I can get away with it.
> > Thanks,
> > Patrick AC0SR