Opto Compressor design
« on: April 14, 2010, 08:47:17 AM »
I've been through so many threads but im in need of some more help. if someone has a few moments to help id be very thankful.

Basically i hae a week to build an optical compressor that has that "musical" edge

I have in my basket on www.maplins.co.uk (im based in the UK)
£50 worth of stuff i think i need to make an opto compressor. but.. im still unsure really
and i have no idea how you power the unit?

Ill be making my own freehand pcb (never done it ) using 1/4" jacks to input and output.

including an on/off switch

pots to use as a ratio control (not sure how to do this yet)

and a capacitor and resistor kit. as im sure ill need them.. lol

(i really am a n00b)

Ive ordered 3mm led's and a grain of rice bulb just to see which is best.

and the LDR's i ordered are 16k-33k is that ok?

last thing was obviously just a plastic housing to hold the unit. any comments, hints,tips, advice !! anything would be GREAT !! thankyou

Also someone helping me how to construct it would help, the links provided are too complicated for what i want, i originally said joe meek style. aslong is it can compress. slightly musically say in the style of a stomp box (as im using 2 1/4" jacks) is fine. Do i need to build an amplifier to run the bulb :S ?!?!

Re: Opto Compressor design
« Reply #1 on: April 14, 2010, 10:31:43 AM »
41 views no reply?

come on guys please ? :( lol !


Re: Opto Compressor design
« Reply #2 on: April 14, 2010, 10:41:14 AM »
Well . . . .

   you are,as you say, a Noob, . . . and just buying £50 worth of bits does not an optical  compressor make . . . If I were you, I'd stick around a while, and get familiar with the search function. If you just want an optical compressor to use with your set-up, then search for LA2A, LA4A, Forsell, What compressor, Jo Cheep, AOC, etc for instance. If you had searched already, you would have come across them straight away. I mean no disrespect, but it is pretty incongrouous for an absolute beginner to design something like an optical compressor from a standing start! I would learn from what is out there already if I were you. There is a lot to learn, from basic electronics to circuit board layout to etching . . . . If you really want to learn about designing, I'd take it real slow. There are plenty of people who can help you here, but it requires more than a little knowledge to get started, and everyone is kinda sick of "neewb" questions asked too quickly, and without thought.

    Good luck!

. . . . RUH ROH . . . . .


Re: Opto Compressor design
« Reply #3 on: April 14, 2010, 11:01:09 AM »
Take a look at this one:


do a google search for "flatline compressor". Theres plenty of info.
You can replace the germanium diodes with Schottky types (1N5817).
Also, you can replace 10Meg resistors at the input with 1M ones, and a 1nF cap with a 10nF.

good luck.
If you sprinkle when you tinkle, please be neat and wipe the seat.


Re: Opto Compressor design
« Reply #4 on: April 14, 2010, 01:52:13 PM »


Re: Opto Compressor design
« Reply #5 on: April 14, 2010, 03:25:03 PM »
IMHO this http://mnats.net/what_compressor.html is the best straight forward optical compressor you can build. See also Kubarth at http://audio.kubarth.com/fredopto/index.html for a very good design. For a more extensive version see http://www.groupdiy.com/index.php?topic=26585.0

Re: Opto Compressor design
« Reply #6 on: April 14, 2010, 05:31:03 PM »
Thank you guys, unfortunately its bedtime here in uk ! so will check out links in the morning, unfortunately i dont have time, i jsut want to create it (bodge style.. probably) in 10 days. im confident i can do it, im on my 3rd year of a degree with 2 years of (VERY beginners electronics) i understand principals, The unit dosnt have to be worth it, or good ! just work haha

thanks alot for the response, better than other forums i frequent


Re: Opto Compressor design
« Reply #7 on: April 14, 2010, 07:19:40 PM »
Wait, you wanna design a compressor from scratch, and learn pcb layout AND etcing, in 10 days? Why the time limit? And what's the purpose?

Hank Dussen

Re: Opto Compressor design
« Reply #8 on: April 14, 2010, 08:46:45 PM »
I really admire your self confidence...

I really do.


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