Gain Brain Clone

I've always been a huge fan of the original Allison Research Gain Brain.  Would anyone out there like to collaborate on a clone project?  Would anyone else want a couple?

Nick Froome

They are cool.  Are they expensive enough to warrant a clone?  They weren't last I looked.  #1 clone suggestion: redesign the meter circuit.  It'd be crazy to reproduce that part. 

I never liked the distortion of the GainBrain, but the concept was cool.  Maybe modern parts?  My $0.02.
Best,
Bruno2000

Iirc, it was based on the TA101 unobtanium transistor-array VCA?

Jakob E.

Maybe the II was, not the original. 

They are pretty great for a certain thing on drums, in RMS.  That's where mine get used.  The peak setting is a recognizable special effect. 

I think the original version was all-discrete

I agree the metering section wouldn't be worth replicating.  I do rather like the perspex front panel - am I right in thinking the Kepex had hidden LEDs and the Gain Brain didn't?

The original went in a 3 or 4 U rack so it'd make a good 500 Series module or could be made as a two-channel-in-1U format

This is the schematic snipped from a bigger PDF, with credit intact

gyraf said:

Iirc, it was based on the TA101 unobtanium transistor-array VCA?

Jakob E.

Click to expand...

Not used in the Allison version.

emrr said:

They are pretty great for a certain thing on drums, in RMS.  That's where mine get used.  The peak setting is a recognizable special effect.

Click to expand...

Agree. 

pvision said:

I've always been a huge fan of the original Allison Research Gain Brain.  Would anyone out there like to collaborate on a clone project?  Would anyone else want a couple?

Nick Froome

Click to expand...

I started a 500 version of this a few years ago.  I was going to use a 3914 for the metering.  I managed to buy a real pair of them really cheap, I lost interest at this point.    The thing is I came to the conclusion that once you had bought the parts, metal work pcb etc  & added some time it would be significantly more expensive than what you can buy originals for. 

Do you still have the pair of originals?  I have been looking for a while with no success. I don't think there were that many in the UK

Let me know if you want to part with them - I am in Sussex as well

I think it'd be possible to spend a huge amount of time getting a clone just right

Nick Froome

pvision said:

Do you still have the pair of originals?  I have been looking for a while with no success. I don't think there were that many in the UK

Let me know if you want to part with them - I am in Sussex as well

I think it'd be possible to spend a huge amount of time getting a clone just right

Nick Froome

Click to expand...

Don't want to part with them.  I got them from the states.  I think I got 4 of them & 2 Kepex gates.  I sold the other 2 to a client in London & still have the kepex somewhere. 

There are actually 2 versions of the Allison Gain Brain.  I think the 2nd one has a transistor missing around where the side chain connects to the meter circuit on the diagram.

The Valley People Dynamite mk I sounds quite similar to the Allison Gain Brain on snare drums.  I have both and sometimes one just sounds a bit better than the other.  This is pretty odd because the Dynamite does use a TA101, so you would think it would be very different to a f.e.t compressor.  I guess it just shows that it's all in the side chain.

IIRC the new Valley People company offers the a replica of the old VCAs as spareparts. I´ll have to research that again...

Was hangin with Dale116dot7 a long while back, and he had built up a gain brain clone that sounded good. I don't think Dale hangs around these parts anymore tho, so...doesn't help much.

I too have always been a big fan of the original Gain Brain and was going to do a 'stereo' version.
I'd planned to put 2 in a Scamp rack.
Then I changed my mind and was going to build the circuitry on a PCB with a 3914 for the metering.
But then it all got put on the back burner and eventually forgotten.
Interesting that someone else had the same idea!

It will be interesting to see if anyone takes this any further.
The manual gives the preferred Vgs for the FET along with the full circuit.

I think the sensible thing to do would be to build a 500  version.  It'd encourage me to get a 500 rack…

I think it'd be a great candidate for parallel compression, so a blend control might be a useful addition. A stereo link and sidechain input would be useful too

As long as it could smash things to pieces, like the original, I'd be happy

Nick Froome

I think there is a side chain input already; yes, I put a stereo link switch on mine and they work fine that way.  I agree it'd be a fine 500 addition, and a pretty cheap build.   

I started working on a 51x clone about 4 years ago
but got side tracked by my Sphere Project and put
this guy on the shelf.  Named this guy after my X wife
"Nancy's Brain" ;D

This is a THAT  Balanced in and out design complete with the
crazy discrete meter.
I really need to get back to this guy when I retire from the
day job this fall.. Maybe the  discrete meter should go.

GARY

Another shot..

gar381 said:

I started working on a 51x clone about 4 years ago

Click to expand...

Looks like you got a bit further than "started"!

Maybe you should rename it & carry on?

Nick Froome

@gar381
Gary. Very interesting.
That 500 Gain Brain module looks really neat. Have you made other changes to the circuitry apart from the input stage ?
I spot a few more i.c.'s on the PCB.

Do have a schematic to show your changes ?

Regards