diod compressor..will this work?..

[skipwave]

RE: Controls

Threshold - The 100k in the feedback loop of first IC in the sidechain. More gain here lowers the actual threshold.

Attack  - The 100k in series with the sidechain diodes.

Release  - The 1M shunting the 1uF capacitor.

Ratio - The 50k in series after the meter.

Take a look at the Forsell Opto Comp (which has a similar sidechain) description here: http://www.diyfactory.com/projects/forsselllimiter/ffosc.htm

 

[Johan]

Could you post back if you get the metering or other quirks ironed out? Also, how's the hiss/noise level?

I think it ( the meter) would work the regular way, just tapping the sidechain between the ratio pot (50k)and the 10k resistor, send it through a voltage follower to the meter and have a bias feed the meter from the other end, to set the meter at "0" at idle..  but it work just the way it is..it just goes up instead of down to show gain reduction...simple and effective...

I havn't got it boxed up yet, and dont have a reliable way of measuring noise level, but just playing music through it, it's not enought to bother me..
j

 

[skipwave]

Thanks for the update, Johan.

I looked at this again today and realized I don't understand the motivation for feeding V-Bias to the sidechain, rather than grounding there. What's the benefit of the sidechain riding atop that bias?

 

[Johan]

Thanks for the update, Johan.

I looked at this again today and realized I don't understand the motivation for feeding V-Bias to the sidechain, rather than grounding there. What's the benefit of the sidechain riding atop that bias?

the idea was that if the diodes are allways switched on, it would/might eleminate any noise from the on/off action..so the sidechain is elevated two diode voltage drops plus one base/emitter voltage drop...I don't know if it makes any reall differance, but better safe than sorry..
j

 

[abbey road d enfer]

It would be interesting to see (hear?) what happens when you vary the bias voltage. Obviously that will change the threshold and initial ratio, maybe in an interesting manner.

 

[skipwave]

Ah, I hadn't considered switching noise. I like your simple, straightforward solution.

abbey's suggestion is interesting, maybe we could tweak the bias from your initial value of "just enough" up to some value of "just how I like it." That'd be cool, if perhaps overly tweak-y.