Reckless compressor - an original feed-forward diode based compressor

[pinkjimiphoton]

jang;enbox is an mxr dynacomp with a switch for the high end snubber in and out. noisier, but more of a treble boost . jim ....err... roger mcguinn does use them, or at least did endorsements for a while. but nothing as cool as an extra eq or treble boost circuit, just undoing one component on the mxr.
i believe the second series may have been a slightly different circuit with a couple more options.

[Ben N]

Just want to report that my Reckless Comp (Rev B) on pcb supplied by Jonny is at long last done, and it is instantly my "main squeeze" for clean, better sounding and quieter than my old Dyna even at high compression settings. Loves a Strat. Sorry no pics, both because my phone camera died, and because I butchered the pretty powder coating on my 125B (tight fit with top mounted jacks) with a runaway drill bit. Eventually I'll figure out a way to rehab the finish, but in the meantime I'm playing it, and loving it. Thanks, Jonny.

[andy-h-h]

I just made a vero for the Rev 4B if anyone is interested.   Sitting over on Guitar FX Layouts in the forum (unverified section).   It does however work, as I just finished making one.

[jonny.reckless]

I couldn't find the layout - can you post a link please?

[andy-h-h]

Sure - hope you don't mind me making the vero.  I did credit you 

http://guitar-fx-layouts.42897.x6.nabble.com/file/n46845/Reckless_Diode_Compressor_Rev_B4.png

[snk]

Thank you, Andy.
Is this design a "typical guitar comp" (aiming at long sustain), or can it be used like a "regular" eq ?

[andy-h-h]

Thank you, Andy.
Is this design a "typical guitar comp" (aiming at long sustain), or can it be used like a "regular" eq ?

This is definitely not EQ, and for the record, it's not my design.  I just did a vero layout for Jonny's design as I liked the sound of the demo.  If you want EQ, try a preamp of some description.   

[snk]

Oops, sorry, the last word was definitively a mistake on my side 
I meant : "is this designed as a "guitar comp" (aimed at increasing sustain, with a limited bandwidth), or can it be used like a "regular studio comp" on bass, drums, full mixes, etc. (if we add pots for attack and relase) ?

[andy-h-h]

Hey snk,

It was designed by Jonny Reckless for guitar, and while I have not tried it on anything other than guitar as I only built one yesterday, I'm guessing it will not be very effective on drums / vocals etc.

Reason being - If you try to use this as an insert on a channel, or plug anything other than a guitar or bass into this, you will most likely run into level and impedance issues.  Running at 9v restricts dynamic range too.

If you want something for studio work, I'd say run with proper rack-mount gear or some nice plugins.    As far as studio grade compressors go, I'm yet to find a cheap way of getting there. 

[jonny.reckless]

I doubt it would be much good as a studio compressor. Typically you would want separate controls for threshold, ratio, attack and release, and some way of doing stereo linking of the sidechain for studio use. It was designed specifically for electric guitar, although I have tested it with bass and acoustic guitar and it works pretty well for those purposes. There is no EQ - the circuit has a flat frequency response. It's a feed-forward architecture with a peak detecting sidechain.

I just thought it would be fun to see if I could make a diode compressor actually work 

[roseblood11]

The  "THAT Jam" is much closer to a studio compressor: https://www.uk-electronic.de/onlineshop/product_info.php?products_id=2945

[forsakenrider]

Hot jam this is cool! I'll need to build one of these, sent a PM about PCB's

[Ben N]

Just wanted to add that I just started using the Reckless Comp as a lead boost into the front end of an ODR-1 clone (Aion Andromeda pcb--big thumbs up for that, too, BTW) set for light-medium rhythm OD, and it's fantastic for this, too, and a more subtle alternative to eq-type boosts. I generally have the compression set between 11-12 o'clock, and the level just audibly above unity, which works both for a clean rhythm setting and as a punchy lead boost, adding a little bit of sing and sustain without being overbearing or changing the tone obnoxiously. Honestly, I can't say enough about this thing. I've got a THAT4301 in the queue for a more bells-and-whistles, super-controllable, anywhere in the signal chain compressor project, but for a simple 2-knob comp, tonally neutral, that just does the job and sounds good, no, great, somewhere in the Dyna-Ross sonic spectrum, without annoying sickly compression artifacts, this is hard to beat.

[EBK]

somewhere in the Dyna-Ross sonic spectrum

 

[Ben N]

somewhere in the Dyna-Ross sonic spectrum

 

Exactly, but without the nasally upper-mid emphasis.

[snk]

Hi,
I am building this compressor, using the veroboard layout posted by Andy above.
Thank you for the great design !

A couple questions :
- Will the Reckless Comp work fine with a bass, or should I tweak a couple values (like the input cap, etc) ?
- Is there an easy way to add a gain reduction indicator led ?
- I do not have any BC556B transistor : is there any alternative giving similar results ?
- Which kind of capacitors are suggested for the two 100nF caps ? green Mylar/box, or ceramic ?

[rankot]

The music is from my band Saint Wry: https://open.spotify.com/album/76AYXUusxuLu0GiVGBQn6q

Really wanted to hear, but Spotify's not available in my country. 

[Ben N]

Going through intense withdrawal -- my Reckless comp crapped out. I haven't had a chance to do any trouble-shooting, other than to check that it isn't anything stupid or easy, like an I/O short (bypass works) or power issue (LED lights). When I dig in, I'll report back.
I suspect this may have something to do with whatever it was killed my Vox MV50AC at the sametime (and that one I can't really troubleshoot or fix, and Korg refuses to do either. Grrrrr.)

[jonny.reckless]

Ben, which revision did you have? I can take a look and see if I have a spare PCB in my drawer somewhere.

[jonny.reckless]

- Will the Reckless Comp work fine with a bass, or should I tweak a couple values (like the input cap, etc) ?
- Is there an easy way to add a gain reduction indicator led ?
- I do not have any BC556B transistor : is there any alternative giving similar results ?
- Which kind of capacitors are suggested for the two 100nF caps ? green Mylar/box, or ceramic ?

It should be OK for bass. Certainly for passive bass.
A small high sensitivity LED in series between R14 and the diode bridge would light up under heavy gain reduction.
Yes a 2N3906 or generally any small signal PNP should be OK.
I used 5mm pitch 50V ceramic caps. I think they are 10% X7R but it's not super critical.