MBP Kompromat (Keeley/Barber OTA Compressor)

[MichaelW]

Build Rating

5.00 star(s)

Another compressor build, I almost have enough new compressors to do another shoot out demo.

I have one more in the pipe to build, the AionFX Aurora (Legacy), which I plan to build as a straight up DynaComp (although you can build either the Keeley or the Janglebox on the same board as well).

At this point I've built all the compressors in the MadBean catalog and all but one in the PedalPCB catalog (due to parts availability I have not tried to build the Creamery yet).

Anyway, the Kompromat is based on the Ross OTA circuit and is supposed to be a hybrid of the Keeley and Barber TonePress.
I'm not familiar with the Barber so I'm not sure which part of this build is the Barber part. The Keeley is essentially a Ross with an attack knob and an input gain toggle (or in this case, potentiometer). I have a retail 4 knob Keeley compressor and it's also got a "Tone" control, one of the main reasons I bought it. I used it for many years before I started DIY'ing.

The Kompromat has provisions to use either a CA3080 or an LM13700 (basically 2 3080's in a single IC). I did not have a 3080 on hand although I do have some en route from CabinTech for the DynaComp build.

Build went super smooth although it's a pretty busy layout. I'm still fiddling with the bias as I haven't quite nailed a setting I'm totally happy with.

I had it side by side with my retail Keeley today testing it and was surprised that it didn't seemingly have as much compression as the Keeley. But I figured out that it was the input gain setting. I pretty much have to have it full CCW which is the highest input gain regardless of whether I'm using single coils or humbuckers to be able to get the same levels of compression as the Keeley (which has the input gain on a 2 way toggle).

I was also surprised by how quiet the Kompromat was in operation and also how transparent sounding it was. I was expecting more coloration and also more noise especially with gain. So those are two pleasant surprises.

Cool build! Cool compressor. After I get my DynaComp built I'll do another comparison video along with the Orange Squeezer thrown in for good measure.

Then I'm going to have to go back through my whole collection of compressors to refresh my memory on how they sound again hahaha.

Purple on Purple (or maybe that's violet?)<-----watch out, color blind guy coming through.....

 

[iamjackslackof]

Do you have a favorite out of all of them?

And I would probably call it purple on pink

 

[Locrian99]

Love the color, I did mine in a mint green with black knobs. This is one I keep thinking I need to add labels to cause I never remember. LOL. I like mine quite a bit. Not a huge compressor guy though, use pretty sparingly mainly when I want some extra sustain and less dynamics from flat picking type of stuff.

Nice lookin build as always.

 

[mkstewartesq]

I built this as a two in one with the General Tso - I wanted a more squashy compressor to accompany the more transparent Tso, and I have been very impressed with the Keeley Compressor Plus I tried, especially its very musical sustain. Now, the Kompromat isn’t meant to be a clone of the Keeley Compressor Plus, so I’m not dinging it for not being what it isn’t, but I wasn’t overly impressed with it. Like you, @MichaelW, I had some difficulty biasing it to where I wanted it to be, and I still don’t think it’s quite there. End result, I don’t use it as much as I thought I would.

I also had an issue where, if the attack was turned fully CCW, I got a bit of distortion on the decay of notes that I was never able to bias out. Did you experience anything similar?

Wonderful build and build report, as always!

Mike

 

[MichaelW]

Do you have a favorite out of all of them?

And I would probably call it purple on pink

Absolutely, my "pair" of General Tso's are my favorite. One is an always one pedal. The second is for dual compressor situations. I'm still dialing in the settings of the second Tso but it sounds pretty good stacked with the attack backed off, the treble backed off and the level backed off a tad.

Part of this latest burst of compressor builds is to see how other non-Tso compressors will stack with my Tso.
So far, I'm digging the way it sounds stacked with a Dyna/Ross on top of the Tso.

 

[MichaelW]

I built this as a two in one with the General Tso - I wanted a more squashy compressor to accompany the more transparent Tso, and I have been very impressed with the Keeley Compressor Plus I tried, especially its very musical sustain. Now, the Kompromat isn’t meant to be a clone of the Keeley Compressor Plus, so I’m not dinging it for not being what it isn’t, but I wasn’t overly impressed with it. Like you, @MichaelW, I had some difficulty biasing it to where I wanted it to be, and I still don’t think it’s quite there. End result, I don’t use it as much as I thought I would.

I also had an issue where, if the attack was turned fully CCW, I got a bit of distortion on the decay of notes that I was never able to bias out. Did you experience anything similar?

Wonderful build and build report, as always!

Mike

Interesting, Yah, sounds like we're both experiencing some of the same behaviors, I also get that little bit of clipping with the "CLIP" full CCW. Also at higher settings, I get some clipping right before the compressors "grabs" the note.
I still think it's probably the biasing, plan to mess around a bit more with it today.