[IN STOCK] L-1 Microcompressor

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L-1
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[IN STOCK] L-1 Microcompressor

Post by L-1 »

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Info here http://l-1.su/Microcompressor.html

[BUILD DOCS AT PAGES 9-10]
[PCB PHOTOS AT PAGE 8]
[UPDATED PROTOTYPES PHOTOS AND PCB AT PAGES 6-7]
NEW EURORACK WIRING-FREE VERSION AT PAGE 19

Image


I always dreamed about easy-to-patch compressor module. I need several units to produce modern dance music. I have two GSSL4000 but it's not enough for me. Only Cwejman makes compressor modules but 700+ $.
Therefore I made MICROCOMPRESSOR - very small but good sounding one.
This is just first prototype. It works very well but not all features added yet. I plan to make PCBs run after testing.
My first project - Hi-quality Quad VCA-Mixer is here viewtopic.php?t=48476

Microcompressor features:
Very quality THAT chips.
Small. PCB will be about 105 x 70 mm.
Fully controllable.
Variable & auto attack & release.
External sidechain in.
Hard/soft knee.
Two devices can be linked in stereo pair.
MOTM Dotcom EURO Modcan power connectors.

I will add:
RMS-AUTO-PEAK switch (detector response mode)
Master-Slave switch (to off slave unit controls in stereo mode)
CV outs, one after RMS detector, second after all controls.

I will NOT add:
VU meter but will make possibility to connect it to board.
VC knee, I don't want to involve device and not sure about usefulness.
VC ratio (see post below).

PCBs will be 2 mm thickness, black glance finish, gold flash pads. Price about 25-30 $ (I don't know now my expenses exactly).
Now I want to know about interest in PCBs and discuss a little about device.

Now I need to make second prototype with all features and test it with some local sound engineers.
Attachments
L-1 MICROCOMPRESSOR 2.JPG
L-1 MICROCOMPRESSOR 2.JPG (104.34 KiB) Viewed 6366 times
L-1 MICROCOMPRESSOR.JPG
L-1 MICROCOMPRESSOR.JPG (99.18 KiB) Viewed 6369 times
Last edited by L-1 on Mon Apr 15, 2013 12:25 pm, edited 16 times in total.
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L-1
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Post by L-1 »

About VC ratio. I haven't found elegant solution for this problem. Some linear VCA is needed here. I considered variant with LM13700 but it's required to add two chips (16 & 8 pin) at least and to normalize cv in to 5V or to make VCA bypass switch. In this case compressor became not micro and to much complicity for this feature (occupy almost half of the board). Variants with matched transistor pairs not fit too - DIP pairs are too rare, SMD pairs and hand-matched I don't want by reason of complicacy for beginners.
If somebody have ideas please post.
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RATIO POT.png
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tony d
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Post by tony d »

I like this idea and will be following your progress.Thanks.
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Paradigm X
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Post by Paradigm X »

Had a sneaky suspicion youd be working on a compressor!

However, I personally cant see the point of making the Attack, release, makeup gain or threshold voltage controlled, to be honest. Ive come from a mixing background, rather than a modular, and just cant see how that would be helpful. Sorry.

A small, two channel (or stereo) compressor, for modular use would be really useful, especially with sidechain. Based on the VCAs you obviously know what youre doing, and i like the feature set, and THAT chips. I was thinking of making the 'one knob compressor' from their design notes.

How much does the VC parts add? Since you done all the work, and all the features are there, just with additional, (IMO) un-needed parts, can you just omit those bits? I guess its just some jacks.

Fitting two into a panel would be great.

Again, sorry, not trying to be negative, trying to understand how those features would be useful. :hmm:

Cheers, and good luck with it. Depending on final pricing i may still get one or two.

Thanks, ben
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Post by L-1 »

I just tried to make something similar to Cwejman compressor, it has all VC parameters. I not sure about usefulness VC too but want to try.
astroschnautzer

Post by astroschnautzer »

I want many.
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Post by keninverse »

I may pick one or two up just for the sidechaining feature...that's pretty cool.
astroschnautzer

Post by astroschnautzer »

Not sure about vc usefulness either, the sidechain could though have a hp an lp filter instead....
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Dave Kendall
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Post by Dave Kendall »

I'm with Ben, that in a mix situation, VC parameters for a compressor are not really that useful. I hardly ever automate compressor parameters when mixing.

But, as part of a modular synth patch, I reckon there could be a lot of fun to be had by dynamically changing a compressor's threshold and attack/release parameters. Changing the character of a VC ADSR, or anything where the Compressor is in a feedback loop could be really quite interesting.

Compressors have rarely been part of a synth's core architecture, yet they often get used on a synth in a mix. I'd say, if it's not a big extra PCB size or component issue, put some extra VC controls/functions in there just for the sheer fun of it, and the interesting things that might come out of it.....

just my 2p worth... :)

cheers,
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Post by L-1 »

Not sure about vc usefulness either, the sidechain could though have a hp an lp filter instead....
You can just split incoming signal and put filtered part into sidechain in.
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Paradigm X
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Post by Paradigm X »

Which THAT chip are you using out of interest, 4305is the only analog engine in DIP im aware of, although you could be using the separate RMS and vca chips.

cheers
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Post by L-1 »

I used 4301 analog engine which combines 2181 VCA, RMS and 3 opamps.
http://ru.farnell.com/that-corporation/ ... dp/1354170
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Spandex
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Post by Spandex »

I'd be interested in a board or two.
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Isaiah
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Post by Isaiah »

Are you inputs DC or AC coupled?

I can't see much use for CV inputs unless the inputs.
But if you could process CV, that could be interesting, I don't know...
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Post by ach_gott »

2 boards for me! 8_)
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Post by L-1 »

Audio ins are AC coupled (in & sidechain on the frontpanel).
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Post by frozenkore »

Two please :guinness:
Cheers!
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Post by oberkorn »

I'm in for two!
you have to pay for the music but the noise is free
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Post by bkbirge »

I'd be interested in 2 and I say keep the VC control.

I bet if you made these also 51x compatible you'd get even more interest over on groupDIY.com .

I think a VC'able attack and release could potentially be pretty awesome for percussion. Put this after an LPG that is doing some ringing I bet it would be magic.

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Post by L-1 »

Maybe I will make add board for balanced ins-outs.
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Post by Thonk Support »

Dave Kendall wrote:I'm with Ben, that in a mix situation, VC parameters for a compressor are not really that useful. I hardly ever automate compressor parameters when mixing.
I spend quite a lot of my working life mixing music and speech and I *do* automate threshold of ducking compressors a lot, release less so, but if I need to vary the speed at which a ducking compressor on music 'heals' again to match the tempo of the piece I will automate release. I don't think I've ever ended up automating attack, knee or ratio though (I'll try anything but that has never stuck ;) )

I'm not even working on anything particularly out of the ordinary in my day job, I'd kinda hope a modular compressor would open up some more experimental CV avenues. The main complaint I've heard about the Cwejman compressor is not the ability to CV stuff, but frankly that the compressor doesn't compare very favorably to other non-modular compressors in the same price bracket.

What I'd be particularly interested in with this module would be the ability to output the CV generated by the RMS detection circuit. This opens up a lot of opportunities to construct esoteric compressors from other devices. A very simple example being the ability to create opto-compressors using an LPG.
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Post by L-1 »

What I'd be particularly interested in with this module would be the ability to output the CV generated by the RMS detection circuit.
I can make buffered CV out.
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Post by Thonk Support »

Great :)
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Post by L-1 »

CV out better before gain control or after? I think after but correct me if wrong.
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Post by Thonk Support »

Hmm :hmm: good question.

I guess ultimately it's a question of headroom?

I'd never considered that the makeup gain would be achieved by the application of an offset to the actual detector voltage rather than being a discrete amplifier at the very end of the chain.

Before the gain seems more flexible possibly as you could still push the MICROCOMPRESSOR into pleasing distortion yet get a 'clean' RMS follower out too?

I don't truly understand the implications of that distinction though!
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