Most versatile compressor build

[Taylor]

I've never really used compression. I think I just never found a use for it, and I never was able to set one to do anything I liked. I'm normally not a "subtle" effects user.

I think, though, that I need a compressor. The problem is that I have no idea what kind I need or what controls I want it to have, because I need to have one to mess with before I'll ever really get compression.

So what I need is the mother of all compressors, that can do the widest variety of comp tricks and sounds, has every control a comp could ever need, etc. In particular I want something that can give me very long sustain. I don't really care about size or difficulty to build. I'm not a golden ears type so I don't need vintage-tone-mojo stuff with exotic transformers, VU meters, etc.

What say ye?

[auden100]

I made a Ross compressor with a blend and boost. That was good. But lately, M. Hammer has been touting the SSM2166 compressor. I was thinking of trying that one out next. It's simple, and has a good range of options for a pedal. Noise gate is a nice added feature. Not sure how the sound compares to the Ross tho.

[Taylor]

Looks good, but I want something with lots of control. Independent continuously variable attack and release controls, threshold, ratio, etc.

[Lurco]

THAT application notes!

[Taylor]

THAT application notes!

A-ha! THAT's the good stuff. (sorry)

http://www.thatcorp.com/datashts/dn115.pdf

I wonder if anybody makes a PCB for this?

[Ben N]

... or even a parts list.

[Taylor]

Hmm, don't follow. The parts are all labeled. The big amp block at the front is part of the THAT4301 chip:

http://thatcorp.com/datashts/THAT_4301_Datasheet.pdf

...?

[StephenGiles]

The side chain looks impressively complicated - must be good

[auden100]

Don't want to sidetrack if you've got your lead, but this recent thread on the q&d compressor looked really promising to me. simple enough to breadboard.
http://www.diystompboxes.com/smfforum/index.php?topic=87300.0

[Thomeeque]

Hmm, don't follow. The parts are all labeled. The big amp block at the front is part of the THAT4301 chip:

http://thatcorp.com/datashts/THAT_4301_Datasheet.pdf

...?

One respected czech builder uses THAT4301 in his Compressor – Limiter guitar stompbox. He swears on this chip, he compares it to tube/studio compressors.There's no schema or something, but somewhere on his page was noted that he used only slightly customized datasheet schemo. So you should be good with this one!

Good luck, T.

Btw. he feeds it with 15V PSU..

[aziltz]

i'd be very interested in a THAT-based comp if someone goes down that road

[blue_lu]

i'd be very interested in a THAT-based comp if someone goes down that road

+1

[wavley]

This... http://www.mercenary.com/fcs-p3s.html is based on the THAT ic and used to be a diy project called Pico compressor, you may still be able to find the schematics and such on the web.  I went to go buy the kit and found out that they stopped selling the kit to make a $1700 unit... after the DIY community worked out all it's bugs, much like Purple Audio and the LA-2A kits.

[blue_lu]

This... http://www.mercenary.com/fcs-p3s.html is based on the THAT ic

I have been looking for pico pcb layouts all over the web, but didn't find a thing. Also many forum topics regarding construction of these things are still in the google cache but actually not available. I guess "someone" erased them...

Lets do a nice comp!

[modsquad]

I have the build document with pcb and schematic, but given that somebody had them all surgical removed I am hesitent to post it.

[blue_lu]

I have the build document with pcb and schematic, but given that somebody had them all surgical removed I am hesitent to post it.

Wow, look at that thread - seems like the pico is really nice!
http://www.gearslutz.com/board/geekslutz-forum/237831-frm-really-nice-compressor-vs-that4301-pico-compressor.html

Fingers crossed that things work out.

Modsquad: what should happen if you post schematics - please enlighten me?

[modsquad]

I am not sure if its the Pico or not but its built on the THAT chip and I would have to compare schematics.   It just appears that someone removed all the links to any schematics or build docs on the Internet that I found.

[bassmannate]

Here's a start. It's not the compressor itself. Just the indicator schematic. But I'm going to poke around a little more. They may still have it up.

[Taylor]

I wonder how necessary it is to run it at +-15v. You could do a charge pump  to get up in that range, but if it's not necessary for instrument levels I'd rather do without.

[Mark Hammer]

I've never really used compression. I think I just never found a use for it, and I never was able to set one to do anything I liked. I'm normally not a "subtle" effects user.

I think, though, that I need a compressor. The problem is that I have no idea what kind I need or what controls I want it to have, because I need to have one to mess with before I'll ever really get compression.

So what I need is the mother of all compressors, that can do the widest variety of comp tricks and sounds, has every control a comp could ever need, etc. In particular I want something that can give me very long sustain. I don't really care about size or difficulty to build. I'm not a golden ears type so I don't need vintage-tone-mojo stuff with exotic transformers, VU meters, etc.

What say ye?

I say that if you have not used one much, or at all, that having MORE controls may not be helpful.  Many adjustments will simply not reveal their added value unless you know what to do with them already.

I would suggest starting here: http://emusician.com/mag/emusic_big_squeeze/  before you embark on projects.  An excellent overview of what was out there a couple years ago, but also of the controls and the sometimes quirky marriage of compressor and program material. 

Personally, I have somewhere around 8-10 compressors of various types, including a nice Ashly rackmount, Alesis and dbx table-top, a couple of different PAiA units, Orange Squeezer, MXR/Ross, 2166-based, and maybe even an EPFM one tucked away somewhere.  The 2166-based one is actually quite nice, once you have the appropriate mods.  The Alesis and dbx have "soft knee" compression which I haven't seen in any DIY projects, thought truth be told I haven't looked very hard.  Given that noise is always an issue with compressors (though often for reasons that have little to do with the quality of the compressor itself), you still want ot have a unit whose layout is as protective of low noise levels as is possible.  In that regard, my advice would be to skip the DIY route and pick something up second hand.  With sop many folks using plug-ins for their studio, you can actually get some nice units for peanuts.  My dbx MC6 was $20.  My Alesis Nanocompressor also cost me around $25, and the Ashly was $50.  I've seen the Alesis 3630 for under $60, and anything Behringer makes or made will probably be in that zone too.  Try to make something with all those controls (and a chassis big enough for them), and especially the gain-reduction indication, and you'll be spending that on parts, easily.