LA-Light - LF rolloff?

[Aren]

I dug up an LA-Light (stompbox version) that I built a while ago, and tried using it in a recording session I had last week. While I can definitely see that the unit does compress (or limit), the effect is either very mild (when the settings are not extreme) or quite exaggerated. In addition, when trying it on vocals, the sound I get appears to be slightly lacking in low frequencies (low mid, to be exact), making it pretty much useless when treating it as a color compressor.
Did anyone else notice these things, or is it just my build? I used two red LEDs and a Radio-Shack LDR (the bigger one. I remember someone recommending it), and a TL072 opamp. Will a different Vactrol or opamp produce better sounding results?

[Johan]

the signalchain through the unit should be flat, unless you put it before a very low input, like a 600 ohm vintage mixer or a mick input. it's designed for typical 10k or more, like most inserts and modern soundcards
the sidechain has LF-roll off thou, to simulate the responce of a electroluminence panel, but that means it doesnt compress lows as much as frequencys over roghly 400Hz...the opposit of your problem (?) ...check the output cap, you might have a too small value there..
if the compressionpot isnt giving you a smoth responce, play around with the value of the resistor siting between the LEDs and the opamp(LED-driveramp)...it can be anywhere from 100Ohm to 1K depending on the LEDs
j

[Aren]

Hmmm... I looked in, and it turns out the vero layout which I used uses a 1uF cap for input and output (probably good enough for a a guitar), while the schematics show 100uF.... I'll heat the iron