GHR Audio

Those 2.5 - 6 -1.2s might be dual time constants like release time position 5 & 6 in Fairchild 660 viewtopic.php?p=37#p37

That makes sense.

The Recom R12-150B is mighty in price. Is there a cheaper alternative you can recommend?

Or a power toroidal backwards also could work, no?

There are no cheaper alternatives for Recom R12-150B as far as I know. Since the whole thing is powered by 15V DC wall wart you can't use a transformer. You could use a linear power supply and a custom power transformer but it might not be cheaper.

What meter is good on this? 200mA? 1mA?

200 uA meter should be used. LED D7 is also gain reduction indicator. If I were to build another one I would just wire LED D7 to front panel and leave out the meter.

I like that idea. Did something like that on analag's DAOC with LED in antiparallel to optocell . But ended up also adding meter slowed down with a cap to show an approximation of average.