Odp: [sdiy] 1/8th inch questions

[Seb Francis]

Roman wrote:

> For 'audio' outputs with 1k ussual impedance, even with connected 10 modules,
> 100k impedance each, it introduces attenuation of (100/10)/(1+100/10)=0.909
> that is less than 1dB. For tuning VCO it can be disaster, as it takes now more
> than 13 semitones per octave. So for tuning outputs (midi2cv, sequencer, etc.)
> one can use opamp with feedback taken from output resistor, put there for
> stability purposes, and not from opamp's output directly.
> No matter how many modules connected, this circuits maintains proper voltage,
> up to opamp's current limits.
>

Wow, that's an interesting point .. especially for me building a MIDI2CV converter at the moment.  I was just going to run the outputs straight from the unity gain non-inverting S&H opamps.  What's this resistor for stability purposes?  Is increasing the output impedance a desirable thing?

Seb