Experiments in compression

[Jubal81]

My 620, its stereo jack and the Janglebox sent me into the rabbit hole of building my own stompboxes and preamps about three years ago. Finally, after lots of circuits and breadboarding I think I'm finally on the path.

What I've done is marry a state variable filter (kind of like an active EQ) with an optical compressor design. It doesn't have quite as much squish as a JB (it's close) but it has zero noise. Just for convenience sake, I also put a SHO boost after the effect on a separate switch. Still some refinement left to do and I'm contemplating making a dual version with a switchable input for stereo operation, even with mono guitars.

Thought I'd share this prototype since this forum put me on this direction years ago.

[cjj]

Ooh, that sounds like a cool design!

[bitzerguy]

Very cool!

[LenMinNJ]

Post some sound clips!

[RickyBubba]

I almost felt like the blonde chick on Big Bang Theory…that sounds like Jibber Jabber!

I understood part of it….hope you post some clips. Sounds like big fun!

[Jubal81]

I don't have any recording equipment at home and iPhone recordings are terrible. Although I think I know a few people who could help me out.

I'm already working on some new compressor ideas I hope to have going sometime this year. In fact, I just ordered a big load of optocouplers and other bits this morning. I've just been playing in mono, but I've been turning over some ideas for a dual independent compressor pair for Ric goodness.

[johnhall]

Really a nice job and some good, original thinking. Wish I could say the same about some others!

[Jubal81]

I've also gotten a great sound from Merlin Blencowe's (of Valve Wizard fame) OTA design he calls the 'Engineer's Thumb.'
It's feed-forward and uses the chip in the feedback path of another opamp, which means it gets the same sound as a Dynacomp, but has dramatically less noise, although more noise than optical compressors.

Here's a link to the schematic: https://www.dropbox.com/s/804zp8qmc3yhe ... bschem.jpg

Sounds really great and I'd take it any day over a straight Dynacomp variant. I'll put in a proper (not plain aluminum) enclosure soon. A lot of my other projects got put on the backburner last year while I was working on this monster:

[Kopfjaeger]

Dude, that is outstanding! Real nice work!! I too would love to hear how it sounds. A comparison, with and without, would be awesome!!

Sepp

[LenMinNJ]

Jason: Are you going to offer these for sale? I'd love to hear one, and based on your description, I'd love to have have one too.

[Jubal81]

Jason: Are you going to offer these for sale? I'd love to hear one, and based on your description, I'd love to have have one too.

I'd consider it, but it's going to be a while - at least a few months or even a year. I have a pretty good idea of what I want to do, but need to do some more testing, then do a PCB layout, order prototypes and then do more testing and put it through its paces.