adding attack and decay (or lag) to simple recitifier?

[loss1234]

i was playing around today with a VERY basic env follower (the gtr goes into a buffer, this drives a cap, one diode to ground and then the other diode into a cap which goes to ground.)

this worked fine. (driving a filter)

however, as soon as i decided to add a variable lag pot (with a cap going to ground) and an opamp follower after it, it stopped working.

SO, my question is, can someone point me toward a Half wave or full wave rectifier with attack and decay?

maybe i should have put the follower after the rect and THEN put the attack/decay?

thanks so much

[CynicalMan]

Here's an envelope filter schematic with attack: www.home-wrecker.com/nurse-quacky.html
Here's a more complex one with both attack and decay: http://urekarm.tripod.com/synth/fuzzyballs1.pdf
In general, the attack can be controlled by a variable resistor in series with the rectifier diode and decay can be controlled by the cap to ground's value.

[loss1234]

funny..that was one of the ones i was looking at today

there is a lot going on in this schematic!

is it just r8 to q2 that i should focus on??

thanks so much

[CynicalMan]

Both schematics have 1k pots in series with 47 or 51 ohm resistors before the decay caps (C1 in the fuzzy balls, the 22uF cap in the nurse quacky). That's what you want to add if you want an attack control.

[Cliff Schecht]

The old PAiA 2700 series module is a classic envelope follower. The only knob is the input sensitivity knob which gives a nice range of slow to quick attack and decay times with just the twist of a knob.