Compact Compressor? For Improving tracking within Octave/Synth combo-build...

[Feral Feline]

The Short of It:
Need a compact small parts-count compressor to reside with and feed my Octaver.

The Long of It:
In many forums, in many threads, many suggestions are made on how to improve the tracking of (down-) octavers and synth pedals alike; the main suggestions being boost the signal input and pre-compression.

So I'd like to make a combo pedal with a built-in compressor before the octaver/synth circuit.​

Less tap dancing and frees up my regular compressor for other duties...​

I'm looking for Suggestions/Pros/Cons for a COMPACT compressor circuit, preferably with minimal controls.
Craig Anderton has suggested a 4:1 ratio with a fairly high threshold, sans "pop" at outset and smooth sustain. He also mentions some EQ tricks, but I'll leave EQ aside for now.

Potential compact compressors I'm considering (in no particular order):

• Hollis Flatline [Madbean Afterlife & 4:1],
• Orange Squeezer and variants (such as Toadworks' Mr Squishy, Ringtone, etc),
• Rothwell Love Squeeze,
• Bearhug (Jon Patton's FET-based comp),
• Bearfoot Pale Green,
• Moosapotamus' Fat & Pretty / Blomdahl's LA-Light,
• Mad Professor Forest Green (has a SUSTAIN mode),
• GGG's Ibanez BP-10/CP-10 copy (cool, uses a BA6110 instead of the CA3080/13600/13700),
• Wayne Kirkwood's TOKC (That One Knob Comp),
• Engineer's Thumb (simple 2-knobber not the 5-knob),
• Demeter Compulator,
• Carlin Comp, [Too Noisy]
• DOD 280,
• DOD Compressor Sustainer FX80B/FX82 (same circuit),
• PAIA Infinity++,
• EHX Black Finger,
• Hexe Tadek,
• mictester’s got a bunch: REALLY CHEAP COMPRESSOR, SIMPLE COMP, BASS COMP, COMPRESSOR SUSTAINER (w/&wo clipping), etc
• MXR Command Sustain,
• Weak Joe, too many knobs
• Really Simple Transistor Compressor,
• Walco Sustainer
• Sam Hay Opticomp,
• EA Comp (purportedly good for bass)
• Craig Anderton Comp
• Clean Squeeze Optical by Myriad Design
• Q&D Cram It, AussieMart and other LM386wMOSFET circuits
• Zirconia Jr (Diamond without the EQ) / Fred Brigg's Diamanté
• PELLUCID
• Trash Compactor, MBP

Some of those listed above are a bit bigger or have more knobs than I want. However...
I'm okay with burying a couple knobs internally via trimmers, but something that is a six-knob comp probably isn't going to be compact enough to stick inside a build paired with an Octaver or Synth circuit — 's gattabee cawmpacked! TC Electronic Sustain+ParaEQ might be an exception.

Comps in 1590A good, 1590B-sized okay, comp needing 1590BB bad.

Needs to be good on bass.

Any other suggestions? (please, no Dyna/Ross)
The list above is really just a drop in the compressor-bucket, I know that's still a big list, which is partly why I'm soliciting help in reducing it. Any thoughts on how to narrow the list down?


Lastly ... though I may have listed a variant above because I briefly looked at a layout and not the schematic...I'm not interested in the Dyna/Ross at all.

[EDIT: Added Pellucid, see post #8]

 

[jwin615]

For sharts and snorts...
Maybe a VCA triggered off the output of the octave/fuzz?
Ala this Penfold bit
May not be perfect, but I bet it could rip

 

[Gordo]

I think the first one you listed, the Flatline is about as simple as it gets. Seems to me the Madbean variant added a blend?

Makes sense what you're trying to do, although the EHX line of sythns and keyboard emulators recommend not using a compressor (which kind of surprised me). Maybe it gets handled internally, exactly like what you're trying to do. I can't recommend the Carlin as the is fairly noisy and I just never got it to behave properly. Any of the optical variants will usually avoid that initial "puck" on the attack.

I'm a big fan of the MB Trash Compactor. The THAT 4305 is pretty versatile and stupid quiet. It's capable of being squishier than opticals but doesn't sound as "effecty" as non-opticals

 

[Feral Feline]

I think the first one you listed, the Flatline is about as simple as it gets. Seems to me the Madbean variant added a blend?

Makes sense what you're trying to do, although the EHX line of sythns and keyboard emulators recommend not using a compressor (which kind of surprised me). Maybe it gets handled internally, exactly like what you're trying to do. I can't recommend the Carlin as the is fairly noisy and I just never got it to behave properly. Any of the optical variants will usually avoid that initial "puck" on the attack.

I'm a big fan of the MB Trash Compactor. The THAT 4305 is pretty versatile and stupid quiet. It's capable of being squishier than opticals but doesn't sound as "effecty" as non-opticals

Yeah, Madbean had the 4:1 (FourOne) [Flatline], which had the dry-blend. It was part of the 1590G series, which I started collecting but Brian discontinued that line before I got a chance to get the 4:1. I've got the 1590A Afterlife [Flatline w/o the dry-blend].

I also picked up the Bear Hug from MadBean, but Bean laid it out for 1590B; so if I go the Bear Hug route I'll use the ELS perf layout which fits 1590A. Or vice versa, use the MB PCB for the Octaver and build a standalone Bear Hug in 1590A.

I've got the MB Trash Compactor (I'm a compressor-junkie), but need to build it up (who am I kidding, I need to build everything up).

Many thanks for the tip on the Carlin, I'll strike it off the list!




Flatline and Bearhug are right near the top of the list.

 

[jcpst]

I use the closed circuit booster limiter to feed my octarock a hot signal.

The appeal to me is right there in the name: 1 knob booser, 1 knob limiter, output control. You can just straight boost with it. Or use the limiter for a little compression. Or smash it hard. OR get a cool overdrive by maxing the boost AND smashing the dynamics.

EDIT: not sure if it’s compact enough for your needs, it’s not really small. 55x50mm

 

[DeadAirMD]

Not sure how easy this would be to implement, but the Mimosa Module from BYOC is ultra tiny. Orange Squeezer type Comp

 

[jwin615]

Yeah, Madbean had the 4:1 (FourOne) [Flatline], which had the dry-blend. It was part of the 1590G series, which I started collecting but Brian discontinued that line before I got a chance to get the 4:1. I've got the 1590A Afterlife [Flatline w/o the dry-blend].

I have a 4:1 stashed if you want to go that route I mail it out.

 

[Feral Feline]

@jcpst Thanks, that Closed Circuit Booster Limiter was off my COMPRESSORADAR™©®. Just came up with what I'd name it!

@DeadAirMD I've got the MimosaJr 1590A board, but had completely forgotten about the module! Will look into that.

@jwin615 TOO KIND! — If I go that route, I will PM you for sure.



I thought I'd included the following, but I had not, adding the following to the list:

Pellucid Compressor: an ultra low noise compressor for guitar and bass

Pellucid Compressor: an ultra low noise compressor for guitar and bass

www.diystompboxes.com

- PELLUCID by Jonny.Reckless
Introducing the Pellucid compressor - a new original design stompbox compressor for guitar and bass. Unlike the Reckless diode compressor, which was a feed-forward design, this is a more traditional feedback compressor design with a two transistor peak detecting sidechain that is derived from the DOD 280, as used in just about every other guitar compressor out there including the Dynacomp, the Ross compressor, the DOD 280 optical compressor, the Diamond optical compressor, the Mooer yellow comp and lots of boutique clones.

The Pellucid uses an LM13700 in the feedback loop of a NE5532 low noise op amp for its VCA. This keeps background noise down to an ultra low level. This is the same basic technique for low noise that is used in the Engineer's Thumb compressor. I've paralleled up both halves of the LM13700 for a further noise reduction, and drive the OTA with a balanced differential signal to minimize control signal breakthrough.

The design goals were simplicity, transparency and low noise. It has a small component count and is made of standard parts all cheaply available from Tayda electronics. It fits into a 1590B enclosure. There are just 2 controls: sustain and volume. Attack and release time are fixed, and both pretty fast, suitable for a wide range of electric guitar styles. The amount of compression available goes from very little (essentially a clean boost) to up to 40dB of gain reduction, which is a massive squish even with single coil pickups. It remains quiet as a mouse even at extreme compression settings due to the architecture and use of a low noise op amp. You could substitute an LM833 or LM4562 in place of the NE5532 if you wish, although the improvement would probably be negligible. I'd avoid the TL072, RC4558 etc as they are generally too noisy for this application.

 

[Paradox916]

The Long of It:
In many forums, in many threads, many suggestions are made on how to improve the tracking of (down-) octavers and synth pedals alike; the main suggestions being boost the signal input and pre-compression

I haven’t heard this before I’ll have to give it a try.

 

[Feral Feline]

Another thing I meant to include in the OP:

OVNILAB​

The all-mighty Ovnilab compendium of compressors from a bass-perspective (well, guitar too, but mainly bass).

While there is an incredible resource of compressor reviews (originated on TalkBass) newer than Cyril's Ovnilab, it is TOO new in that most things reviewed are not in the DIY domain, whereas a LOT of the stuff on Ovnilab can be DIY'd whether on vero, perf, PCB or even just a schematic so I can do my own layout.


Just want you folks to know I'm not idly waiting for you to choose something for me, I'm doing my homework and actively assessing stuff as I go.
This thread's already come up with a couple gems I overlooked, namely the CCBL SoloDallas jobby Jcpst mentioned and the BYOC Mimosa Module DeadAirMD re-acquainted me with and the thread helped Gordo steer me clear of the noisy Carlin — this sort of help and info is exactly why I started the thread.

THANK YOU!

 

[zgrav]

I think this does not fit your low parts count requirement, but using a compander to compress the signal going in to the octave and then expand it afterwards was used in Craig Anderton's Roctave Divider. The NEC 570 chip could also just be used as a compressor.

 

[Feral Feline]

Cool stuff. I'll revisit the Roctave Divider.

Those NEC570 ICs aren't cheap, though.
It did lead me to an application note for NE577 and NE578 compandors.
Mind, I'm still learning to crawl when it comes to circuit design, let alone taking baby steps.

For the moment, I'll keep trying to stick the square block through the triangle hole... ie paint by numbers and house a couple of existing circuits together.

 

[Gordo]

4:1, yeah, that's it. If jwin's board doesn't pan out I have a sneaking suspicion I have it built up. I really tried to like Jon's Bearhug because I like Jon but just never got on with it. I have a spare Carlin board if you ever want to mess with it. It reminded me of early Montrose attack and distortion so I think I named it accordingly. I loved the sound into a Lab Series amp but it was a bit too noisy unless I rode the bypass which got to be too distracting.

 

[zgrav]

I thought that I had built something from PPCB in the last couple of years that used a compander chip but can't nail it down. I thought it might have been the flock harmonizing fuzz, but nope.

 

[Feral Feline]

Can't help you there Zgrav — thought it might've been the SSM2166 thing from AMZ and then noticed you'd said "PPCB".


I'm narrowing down the choices, and a little bit slowed-down and sidetracked by an older compressor idea I had involving the Pale Green and Forest Green comps designed by Bjorn of BJFE fame. Then I started looking at my old notes about mods for the Jordan Boss Tone, which lead to... OH! LOOK!

Reading through all the Ovnilab reviews again and whatever I can find on forums, I think the Orange Squeezer (Mimosa, Julius etc) is out. It's a cool effect, compact, but the OS tends to lose lows a little (does this even matter since it’s being "octivated"?). Nonetheless, it's the OS nature and character that knocks it off the list, it isn't about smooth sustain. I may still build up a Toadworks Mr Squishy clone (OS-based) which adds a little more control, but ...

The stuff I've read about these:
Flatline (MBP 4:1/Afterlife)
Rothwell Love Squeeze (I've got one built up, somewhere, unboxed)
Bearhug (Patton partially based it on the Rothwell, but is its own thing)
Philosopher's Tone (quite a bit bigger and more complex than I wanted, but if it does what it's supposed to do...)
Milk Box is another good sustainer like the PT above ...

It doesn't even really need to be a hardcore sustainer thing, its job is simply to make the octaver/synth able to track the pitch a bit better.
There's still a lot of outliers to explore, with little info to go on. I see a lot of breadboarding and perf builds ahead of me, because ultimately I've come to realise (sorta knew it all along) I'll simply have to build up the short-listed ones and try them each with the Ocelot/synths/etc — THEN build the combo(s).


New idea: Build the comp separately but with a loop, so the comp can be used stand-alone or stick octaver/synth/whatever in the loop. I still get the one-stomp reduced tap-dancing, but a lot more flexibility in mixing and mashing things together. Nah...
STICK TO THE PLAN!
Simple, small parts-count, cram it in...

 

[zgrav]

Interesting point about what needs to be done to the incoming signal to get better tracking for octave down. For octave up effects the general comments are to pick single strings from the 12th fret and up. But for that, an octave down is basically the unfretted string. Maybe the reason for fretting the 12th and higher for the octave up is to generate tones not otherwise available on the neck. Compressing makes sense to avoid overloading the octave circuitry and it makes sense to go for a low parts count that will still give you the kinds of speed and some dynamic range you want in the lower frequencies. One reason I like the 4-in-1 is that it still gives you the dynamics of the incoming signal while then boosting and compressing the main part of the signal.

 

[Feral Feline]

Down-Octavers (&synth-tracking) generally works best when playing on the neck pickup, even-plucking near the neck, and the tone rolled off, single notes — everything working towards giving the octaver/synth a solid steady fundamental to latch onto; all of which helps get rid of upper harmonics that may confuse the tracking circuitry.

Not many analogue down-octavers will hold a note on a bass-guitar's low E, up that string to the A at the 5th fret (no idea about a low B-string at the 5th fret on a fiver); usually you see (4-string) bass-playerswith analogue-octavers playing between the 5th and ... 14th fret or higher if they're soloing, but yeah, grooving is done mostly around the 5th fret and up a few more frets — the balance point between good tracking and good octave sounds. I've mainly messed around at home with my OC-2, few gigs (99% of mine were on upright) — so anything I've regurgitated may not hold true for a pro-musician.


If this experiment works well with the PPCB Ocelot, I might draught in a few more compact-comps for some of the synthier Parasit builds.