Vari-mu compressor project

Hi groupdiy,

This is my first post!

Does anyone know of a vari-mu compressor project available?

I have just finished the G9 micpre and the G1176 and they are both fantastic (thanks a lot to Jakob).
But I need one compressor more for my recording projects and I think it could be cool to build one of those sexy vari-mu compressors.

I am not a newbie, but I'm not experienced either, so I don't think I am able to build a compressor directly from a schematic.

By the way, thanks for a very nice, cosy forum. :grin:

All the best,
Frede

Hej Frede (endnu en århusianer her :green: )

Here's PRRs VariMu;

http://music-club.rutgers.edu/headfonz/comp5/Comp5.html

Someone made a page.. Kent, I think? I don't have the url though..

Hi Sismofyt (det var da hyggeligt!!! :thumb

Thanks, I'll check that out...

But has anyone yet built PRR's Varimu compressor?
Kelley

Frede, here you will find some links: http://www.groupdiy.com/index.php?topic=2687

Yes, there it was!

www.conditionedresponse.com/DIY/C5/index.html

I keep forgetting the METAs.. :roll:

Hey, another one from Århus..

Welcome to "The Lab", Frede!

It looks like we could soon gather people enough for a local branch of "The Lab"

Jakob E.

has anyone ever built anything close to a ua 175 or 176? Ive never seen a schematic for one of those, dont knwo how involved that would be on the unavailable transformers frontier, but that would be interesting to look at.

dave

Is Århus the 'silicon valley' of Denmark?
Jakob, maybe you infected this city with a dangerous virus. :grin:

wow, not a whole lot going on in a 175... gets the wheels turning.

dave

The DISA looks nice, Jakob have you heard an original? You don't have one at Feedback, do ya :?: :green:

Denmark & Århus is so small we don't have space for a silicon valley.. maybe a silicon street :? :roll:

DIY, any kinda DIY, have always been quite popular here..

No, we don't have any DISA out here.. DR, the radio section in Rosenørns Alle' in Copenhagen used to have a set of them (that they did not use..)

But the DISA comp would be very hard to diy, both because of the tubes, and because of the JS transformers they use..

All the vari-MUs use custom trannies it seems, so it really doesn't matter. I'd think we could get replicas that would work.. and I do have eight 6386 I'd like to use :wink:

The CBS rIIz uses a single 6386, and I reckon it would be a simple diy job:

http://www.gyraf.dk/schematics/CBS_Audimax_440.gif

http://www.omnipressor.com/Other/CBSvarimu/

(scroll to modcomp link on the above for the attck/rel adaptor schematic)

You would leave out the front end circuitry for the two 6DK6 which would leave the project needing the following:

1 x 5Y3 RECTIFIER
1 X 6AL5
1 X 0A2
1 X 12AU7
1 X 6386

1 X Input transformer
1 X O/P transformer
1 X 1ma meter

I also have a schem for the stereo adaptor. As standard it uses 3 rare-as-rocking-horse-shit UTC transformers. However, the one I have has been adapted to use only 2 Belclere trafos as the UTCs were removed when I got it.

The rIIzs were used by radio stations for many years, and the pair I have sound pretty good although you don't want to apply too much squash. The time-constant controls work pretty well, the adaptor mod is tested.

IMHO the rIIz must be one of the cheapest all-valve vari-mus you can find, no interstage transformers and 5 valves. Just a suggestion!

Justin

Edit : Nevermind :roll:

Well, Belclere means, OEP!!!