LA-2A compressor as pedal?

[moosapotamus]

...makes you sound very big and warm...also great for bass...if you dont like it, you can make the cap bigger or the resistor smaller...

Well, I do like it. I think it's quite 'natural' sounding, too. I'm just wondering if it would be useful to have a few different settings there. I'm also on the brink of building myself a decent dual-channel mic preamp (like, maybe the green pre, or something) and was thinking a little opto comp on each channel might be a nice add-in.

Thanks
~ Charlie

[puretube]

the E-H new "Blackfinger" tube-comp-pedal is based on the same principle;
as is the new "NY-2A" studio 19" stereo tube compressor...

[casey]

...and bipolar powersupply is when you have booth + and - voltage...if you run on a single 9volt battery you will need the two resistors at the far right in the schematic above. with a bipolar supply, thats allready taken care of...

sweet....so all i have to do if i leave the two resistors in as listed in
the schem....is just use a regular power supply and connect
neg to neg and pos. to pos....  correct?  would more voltage
increase headroom in this particular circuit ?

thanks for all of the help because i am going to build this one.
i do alot of recording and cant wait to put this through it's paces.

what type of ratio are we talking here?  attack and release?
thanks for all of your help.

[Johan]

sweet....so all i have to do if i leave the two resistors in as listed in
the schem....is just use a regular power supply and connect
neg to neg and pos. to pos....  correct?  would more voltage
increase headroom in this particular circuit ?

thanks for all of the help because i am going to build this one.
i do alot of recording and cant wait to put this through it's paces.

what type of ratio are we talking here?  attack and release?
thanks for all of your help.[/quote]

You've got it....higher voltage= better headroom...the ratios are roughly 1:3 in "comp" and 1:10 in "limit"..in reallity they are booth limit but this was what the old LA2a manual said..the input resistance network could have been simplyfied but I wanted it to stay as close to the original as possible, including the dynamic loading, wich is why I didnt put a buffer at the front. the attack/ release is more or less determined by the lag in the LDR, so if you're not using the VTL5c2, you might want to try a few different LDRs

Johan

[casey]

SUPER COOL.

Thanks for the great project.

[martin beer]

OK, I'm coming to the party a little late, I know, but I have something to enquire of any studio-minded people.  Namely, if I wanted to compress my whole mix through a pair of these, how would I go about achieving a stereo compressor using this design?  Would it be a matter of using a single driver stage for the LED side (U1b), using a summed mono signal as an input, then using this to light the LED's of both my left and right side compressors?  Or might it work OK to use two independent compressors, but with shared controls (although I've heard that this does strange things to the stereo image)?  Any ideas?

[Johan]

OK, I'm coming to the party a little late, I know, but I have something to enquire of any studio-minded people.  Namely, if I wanted to compress my whole mix through a pair of these, how would I go about achieving a stereo compressor using this design?  Would it be a matter of using a single driver stage for the LED side (U1b), using a summed mono signal as an input, then using this to light the LED's of both my left and right side compressors?  Or might it work OK to use two independent compressors, but with shared controls (although I've heard that this does strange things to the stereo image)?  Any ideas?

the easiest way would probably be to just build two and then use dual pots for the threshold and gain. so that one dual pot connects two both channels threshold and the other two both channels gain.
you could also make a separate sidechain with the inputs from both channels mixed, but it get a little more complicated and I dont know if its worth the extra effort.

Johan

[Phorhas]

What part values should I change to suit it for Bass use?

And I'm guessing that 9V won't cut it, too. will 24v single rail be enough?

[Johan]

I use it just as it is and it sounds right to me, but you could change the 0,2uF cap just before the LEDs in the sidechain to a bigger value...the rest of the circuit is pretty much flat in frequencyresponce..

Johan

[Phorhas]

Thanx buddy

[ragtime8922]

OK, I'm coming to the party a little late, I know, but I have something to enquire of any studio-minded people.  Namely, if I wanted to compress my whole mix through a pair of these, how would I go about achieving a stereo compressor using this design?  Would it be a matter of using a single driver stage for the LED side (U1b), using a summed mono signal as an input, then using this to light the LED's of both my left and right side compressors?  Or might it work OK to use two independent compressors, but with shared controls (although I've heard that this does strange things to the stereo image)?  Any ideas?

      You may want to inquire about this on Robert Keeleys site to see how he does it. He makes a rack unit that is simply two of his pedal circuits wired together. I don't know if there is something special to it or if he just wires them together.

      BTW, great thread!!!