META - Vari-µ compressors

This is a meta-thread, made to allow you to keep track of the posts concerning this single issue - I will continue re-editing this first post.

- All should be contained in this first post - which is re-edited regularily.

- Everyone is welcome to reply with comments and pointers to things they consider relevant. This will be copy/pasted into the first post, if the meta-keeper finds it relevant. (I deeply dislike censorship, but here it seems necessary for the sake of overview)

- On a regular basis, Kev deletes all posts but the first, and bumps it to the top.
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Forum links:

http://www.groupdiy.com/index.php?topic=111
PRR Vari-µ - OEPs good for this project?

http://www.groupdiy.com/index.php?topic=148
AWA Vari-µ limiter - restaurating an AWA G54639 Limiter

http://www.groupdiy.com/index.php?topic=208
Who was making the Fairchild - Kent is planning to clone a Firchild 660

http://www.groupdiy.com/index.php?topic=257
Variable-µ tubes have the ability to reduce their µ...??? - PRR about Vari-µ in general and the potentially misleading description in the UA webzine in particular.

http://www.groupdiy.com/index.php?topic=308
Low-cut when vari-µ comp is engaged? - The need of a low impedance source when messuring freq plot

http://www.groupdiy.com/index.php?topic=909
Variable-mu lives!!! - Dale has sucessfully finished his Fairchild-like compressorcompressor

http://www.groupdiy.com/index.php?topic=1165
Modifying PRR Vari-Mu Compressor for +4dB Operation

http://www.groupdiy.com/index.php?topic=1463
low input gain on UA 176

http://www.groupdiy.com/index.php?topic=1509
Got my 6BC8's - think about UA 175A - Jürgen has scored some 6BC8 and is now thinking of a Vari-µ

http://www.groupdiy.com/index.php?topic=1626
UA 175, or how much power can a 12BH7 stand? - Jürgen is scared about what the UA175 will do with it's tubes

http://www.groupdiy.com/index.php?topic=2080
AM864 lots of HEATER current

http://www.groupdiy.com/index.php?topic=2580
UA175 variable mu compressor output transformer calculation

http://www.groupdiy.com/index.php?topic=2711
Alternative to 6386 tube

http://www.groupdiy.com/index.php?topic=3438
Another PRR Vari-Mu question... - Some additional infos about the PRR Vari-Mu Compressor

http://www.groupdiy.com/index.php?topic=3587
EMI-style mod instructions for altec 436a compressor @ ebay - a discussion about seeling infos on ebay and some useful infos about 436 modding

http://www.groupdiy.com/index.php?topic=4465
Federal AM864/u mods and MAXSON Dept. of commerce

http://www.groupdiy.com/index.php?topic=4756
Daven T attenuator/BA6A questions

http://www.groupdiy.com/index.php?topic=4570
RCA BA6A limiter

http://www.groupdiy.com/index.php?topic=4805
homemade BA6A - A picture of a home made BA6A

http://www.groupdiy.com/index.php?topic=4951
Questions For Fairchild Inventor - A list of questions together for an upcoming chat with 670 guru Rein Narma

http://www.groupdiy.com/index.php?topic=4955
UA175 inspired variable Mu compressor - Jürgen has finished his power supply

http://www.groupdiy.com/index.php?topic=5255
Transformerless Varimu Compressor - Is it possible to design a transformerless vari-µ compressor?

http://www.groupdiy.com/index.php?topic=5611
Pre amp & Collins AM864 compressor combined, ideas needed

http://www.groupdiy.com/index.php?topic=5828
Federal Am864/U limiter attenuator problem

http://www.groupdiy.com/index.php?topic=5994
Input tran ratio for Federal AM864/U limiter?

http://www.groupdiy.com/index.php?topic=6349
Variable Mu and beginners quest

http://www.groupdiy.com/index.php?topic=6352
Vari-mu tube matching criteria

http://www.groupdiy.com/index.php?topic=7264
Vari-Mu Compressor Project - analag presents his Slightly tweaked Altec 436c

http://www.groupdiy.com/index.php?topic=7517
Federal AM864 troubleshooting help

http://www.groupdiy.com/index.php?topic=8680
670 with solid-state side-chain?

http://www.groupdiy.com/index.php?topic=10097
6L7 vari-mu compressor design

http://www.groupdiy.com/index.php?topic=10326
AM864 repro?

http://www.groupdiy.com/index.php?topic=106368
stereo link in vintage vari-mu units

http://www.groupdiy.com/index.php?topic=11469
Bauman Neve output in a PRR varimu - PRR presents a discret Neve output stage and a discret side chain

http://www.groupdiy.com/index.php?topic=11555
My New Project?? - Collins Limiter

http://www.groupdiy.com/index.php?topic=11681
Federal Limiter AM864 thread

http://www.groupdiy.com/index.php?topic=11739
Best way to pad an Altec 436c - Mod of the gain structure of the Altec 436c

http://www.groupdiy.com/index.php?topic=11759
Some "vary-mu"-related patents - presented by NewYorkDave

http://www.groupdiy.com/index.php?topic=11814
Another vari-mu: Chriswik Reach Compressor

http://www.groupdiy.com/index.php?topic=12122
schem for vari-mu compressor w/ pcc189?

http://www.groupdiy.com/index.php?topic=12530
PC900/4ha5 or 6gk5 for vari mu compressors

http://www.groupdiy.com/index.php?topic=13252
varimu²



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External links:

http://music-club.rutgers.edu/headfonz/comp5/Comp5.html
PRR Vari-µ - PRR Vari-µ explained

http://www.conditionedresponse.com/DIY/C5/index.html
PRR Vari-µ - Kent has built the first PRR Vari-µ

http://www.omnipressor.com/Other/Altec.html
Altec 438 - Zebra50's Altec 438 preamp/compressor clone

http://www.uaudio.com/webzine/february/text/content4.html
Compression Obsession: The Universal Audio 175 and 176 - Universal Audio is talking about their old boxes

http://www.robflinn.eurobell.co.uk/
Rob Flinn - Altec 436c & Gates Sta-Level

http://www.digital-synthologie.de/vari-mu/index.html
Vari-µ and Pultec EQ in one box

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Schematic links:

http://www.waltzingbear.com/Schematics/Gates/Sta_Level.JPG
Gates Sta-Level

http://www.sowter.co.uk/schematics/rca_ba6a.jpg
RCA BA-6A Limiting Amp
http://www.waltzingbear.com/Schematics/RCA/BA-6A.JPG
RCA BA-6A Limiting Amp - simplified schematic

http://www.waltzingbear.com/Schematics/Urei.html
Universal Audio 175A, 176, 177

http://www.waltzingbear.com/Schematics/Misc.html
Collins 26U1 Peak Limiting Amp, Collins 356E-1 Limiting Amp, FAA AM-864 Limiting Amp, FAA CA-1589 Limiting Amp, GE BA 5A Limiting Amp, WE 1126 Limiting Amp

http://recordist.com/ampex/schematics/altec/436atl10.pdf
http://www.purpleaudio.com/pdflib/altec438Acomp.pdf
http://www.triodeel.com/al444b3.jpg
Altec 436C, 438A 444b

http://www.digital-synthologie.de/vari-mu/download/u73.gif
TAB U73 - German broadcast vari-µ limiter

http://www.digital-synthologie.de/vari-mu/download/disa91n.gif
Disa 91n

http://www.gyraf.dk/schematics/CBS_Audimax_440.gif
CBS Audimax 440

http://www.kubarth.de/diy/fairchild/index.html
Fairchild 670 - The big one

..Cleaned meta..

remember the META?

I actually still use them while looking for specifics.. But our local search has become so much better over the years..

/Jakob E.