META - passive equalizers (Pultec, NYD-EQ & more!)

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Viitalahde

Well-known member
Joined
Nov 7, 2005
Messages
727
Location
Kuhmoinen, Finland
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, replies will be copied to the first message and deleted, then bumped to the top.
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FORUM LINKS

Project specific discussions:

http://www.groupdiy.com/index.php?topic=4107
>> NYD-EQ discussion

http://www.groupdiy.com/index.php?topic=228
>> DIY Pultec EQP-1A Layout and Pics - Cayocosta's nice looking point-to-point Pultec with excellent wiring information and pics of the finished unit.

http://www.groupdiy.com/index.php?topic=362
>> Bluebird's absolutely massive version of NewYorkDave's passive EQ. With pics and schematics. Respect!

http://www.groupdiy.com/index.php?topic=4107&highlight=eq
>>The NYD EQ - lots of good discussion about this project I'm working on when I get the time for that..

http://www.groupdiy.com/index.php?topic=826&highlight=pultec
>> Discussions on the frequency response of the Gyraf Unit:

http://www.groupdiy.com/index.php?topic=7474
>>How to turn a Pultec into oscillator - a nice and simple trick to turn your existing unit to a test oscillator!

http://www.groupdiy.com/index.php?topic=751&highlight=pultec
>> Parts List and Photos of ChuckD's finished unit:

http://www.groupdiy.com/index.php?topic=779&highlight=pultec
>> Mattiahs' hum problem:

http://www.groupdiy.com/index.php?topic=2238
>> A topic about the White passive EQ -with schematics and discussion of making it both boost and cut

http://www.groupdiy.com/index.php?topic=11342
>> Buttachunk & MR.T pity normal Pultecs and want a low frequency boost only version

http://www.groupdiy.com/index.php?topic=5429
>> gyraf pultec build in the 110v (us) and transformer heat - mains transformer discussion of the Gyraf Pultec

http://www.groupdiy.com/index.php?topic=16390
>> A question on a solid state Pultec with a 2520 op amp

http://www.groupdiy.com/index.php?topic=6501
>> Solid state amp for Pultec EQ?

http://www.groupdiy.com/index.php?topic=2534
>> Mid cut filter for basic Pultec circuit?

http://www.groupdiy.com/index.php?topic=16745
>> General discussion about the Gyraf Pultec and all..

Coils & capacitors:

http://www.diygallery.de/DIYsites/inductor.html
>> Steffen's take on DIY inductors .. Very cool!

http://www.groupdiy.com/index.php?topic=77048
>> Matthias's nice inductor test - the audio files are gone but the discussion is still worth reading

http://www.groupdiy.com/index.php?topic=744&highlight=pultec
>> Discussions about Caps for a Passive EQ:

http://www.groupdiy.com/index.php?topic=411&start=0&postdays=0&postorder=asc&highlight=
>> A topic about passive EQ maths

http://www.groupdiy.com/index.php?topic=2753&highlight=pultec+inductor
>> Choosing Pultec Inductor and Cap Values - CJ explaining this thing well! Not only for Pultecs but all passive EQ's.

http://www.groupdiy.com/index.php?topic=6810
>>Chokes any good for Pultec EQ? - a list of inductors & specs of them.

http://www.groupdiy.com/index.php?topic=6195&highlight=fastron
>>Gyraf Pultec inductors - NewYorkDave trying to desperately convince people going for the Fastron inductors! Believe him will you?? :razz:

http://www.groupdiy.com/index.php?topic=14093
>> Alk509's hand wound inductors.

http://www.groupdiy.com/index.php?topic=20714
>> A peek inside the Cinemag inductor..
GENERAL INFO, TIPS & SCHEMATICS

http://www.gyraf.dk/gy_pd/pultec/pultec.htm
>> Jakob's page of the DIY Pultec.. Started it all!

http://www.recproaudio.com/diy_pro_audio/pultec_eqp1a.htm
>> Cayocosta's nice page for a DIY Pultec. Good work!

http://i74.photobucket.com/albums/i276/velvettone/EQP-1A3Schematic.jpg
>> EQP-1A3 schematic - the one with the 2520 amp.

http://home.t-online.de/home/micro.wave/inductor.html
>> Steffen's introduction to DIY inductors..

http://www.diygallery.de/DIYsites/stpultec.html
>> Steffens transformerless Pultec with BA283 output stage

http://recording.org/users/kev/Inductors.htm
>> Kev's page for inductors at RO..

http://home.online.no/~jaeioluf/sound/eqpassiv.htm
>> Basic passive EQ theory.. Good!

http://www.danalexanderaudio.com/Outboard.html
>> Lang PEQ-2 schematics and datasheets for different Pultecs at Dan Alexander Audio!

http://www.testecvw.com/carl/images/ImpedanceNomograph.pdf
>> Impedance nomograph Check this out for designing passive filters..

http://www.vacuumbrain.com/docs/pultec.html
>> Pics of Pultecs & a layout diagram for EQP-1A

http://www.uaudio.com/webzine/2003/june/index2.html
http://www.uaudio.com/webzine/2004/april/content/content4.html
http://www.uaudio.com/webzine/2004/july/content/content4.html
http://www.uaudio.com/products/software/UAD-1/pultec/demo.html
http://www.uaudio.com/products/software/UAD-1/pultec-pro/demo.html
>> UA explaining Pultecs. Plugins - bah!

FINISHED UNITS

http://www.groupdiy.com/index.php?topic=125527
>> Zee1usa's nice looking GQB-1A twins

http://www.digital-synthologie.de/pultec_discrete/index.html
>> Michael Krusch's version of the BA283 Pultec..

http://img.photobucket.com/albums/v292/chrissugar/CMS-LAB-MEQ1/CMS-LAB-MEQ1-FRONT-1.jpg
http://img.photobucket.com/albums/v292/chrissugar/CMS-LAB-MEQ1/CMS-LAB-MEQ1-BACK-2.jpg
http://img.photobucket.com/albums/v292/chrissugar/CMS-LAB-MEQ1/DSCF2296-P-R.jpg
http://img.photobucket.com/albums/v292/chrissugar/CMS-LAB-MEQ1/CMS-LAB-MEQ1-FRONT-DETAIL-1.jpg
>> Chrissugar's mastering EQ.. :shock:

http://www.groupdiy.com/index.php?topic=4088
>> Jrmintz's hybrid Pultec

http://www.groupdiy.com/index.php?topic=13802
>> Nrgrecording's extremely well cloned outlooks of the EQP-1A with tiny amps..! :twisted:

http://www.groupdiy.com/index.php?topic=9563
>> Radiance's solid state Pultecs

http://www.groupdiy.com/index.php?topic=12992
>> My take on the NYD-EQ

http://www.groupdiy.com/index.php?topic=13114
>> NYD himself built the ghetto edition of his passive EQ
 
"Pultec Inductors again..." - dissection and analysis of the pultec inductor - serious goodies by CJ...

http://www.groupdiy.com/index.php?topic=25482&postdays=0&postorder=asc&start=75

Jakob E.
 
Some study aids on one mid pultec variant start here; just the last paragraph and pic link on that first link.  These are all on the same thread page:

http://www.groupdiy.com/index.php?topic=27964.msg493508#msg493508
http://www.groupdiy.com/index.php?topic=27964.msg493611#msg493611
http://www.groupdiy.com/index.php?topic=27964.msg494342#msg494342
http://www.groupdiy.com/index.php?topic=27964.msg496474#msg496474
 
VintageWindings "Pultec EQP-1A Facts & Fiction" - nice and through description of the Pultec EQ  - http://www.vintagewindings.com/tech%20swag/Pultec-Facts-&-Fiction.pdf

Jakob E.
 
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