Why is this please???? Was: RE: [sdiy] MFB SEQ-02 question

[Dave Kendall]

Hi.

On Jan 6, 2010, at 09:26, Neil Johnson wrote:
> Oren Leavitt wrote:
>> As a more permanent solution, you (and MFB) may want to employ an 
>> output buffer design with that small resistor within the feedback 
>> loop of the buffer. That will isolate capacitive loading without the 
>> resistor introducing error when the CV output is loaded.
> Here are a couple of examples:
>
> http://www.milton.arachsys.com/nj71/pdf/cesyg/vcf-sch.pdf
> http://www.milton.arachsys.com/nj71/pdf/cesyg/vclfo-sch.pdf
>
> In both cases the output buffers have a 100R resistor on the op-amp 
> outputs to deal with capacitive loads (long shielded cables, for 
> example).

If using a simple non-inverting op-amp buffer, is it possible to 
include the output resistor *within* the feedback loop, or is it better 
to add it outside, directly on the output?
I've also used a NON-INV buffer before, with a voltage divider between 
output and GND with the wiper wired to the -input of the opamp to vary 
the output level. Would this work with the 330r inside the feedback 
loop, ie between the output and the input to the voltage divider?

cheers,
Dave







>
> Cheers,
> Neil
> --
> http://www.njohnson.co.uk
>
>
>
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