DOWNLOAD: Pultec-1977_catalog

Units covered, with text, specs, and photos, include: Pultec EQH-2, EQP-1A3, and MEQ-5 equalizers; Pultec HLF-3c and HLF-26 filters; Pultec SP3 and MH4 mixers.

Until I saw this catalog I had not realized that the original Pultec production run had extended into 1977.  These are the solid-state Pultecs, not the more coveted vacuum tube units that trade in the $5000 range, but AFAIK the actual equalization stages are the same as in the earlier tube units.  I have never scratch-built a Pultec clone, largely because the idea of hand-building the multi-tapped inductors always seemed a little daunting to me.   I recently found myself in possession of a large batch of various MiniDuctors, though, and I am wondering if these can be put service in a Pultec-type circuit.  The mH values are very close to those in the putlec schematics, but I cannot find any reference online to anyone building a Pultec using MiniDuctors rather than a large coil-wound inductor.  Anyone have any idea about this?

Pultec equalizers have enjoyed fifty-plus years of popularity among recording professionals.  Much like the first several compressors released by Universal Audio/UREI, they have never really gone out of style.  And if vintage Pultecs seem expensive these days (and they no doubt are…), remember that there is an inflation factor of 11x from 1961 to 2012.  So the value of these pieces has more or less simply risen with inflation.

Download catalog data on the EQP 1, shown above: Pultec_EQP-1

Download catalog data on the EQH 2, shown above: Pultec_EQH

Download catalog data on the HLF, shown above: Pultec_HLF-3

The Pultec MEQ-5 and SP-3 Stereo Panner of 1962.  As unlikely as it might seem, the ‘pan’ knob was, at one time, a new and novel concept. 

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Ok so these are not outboard so much as inboard but you get the connection.  The Langevin EQ-252A, EQ-251-A, and EQ-255 filters of 1961.

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Above: the Universal Audio 175B limiter is announced.  The 175B is quite similar in operational principle to the Altec 436/8 and the Gates Sta-Level but the UA is far more sophisticated.  Just a really smartly designed piece of AFAIK, it was sold like shown, with no top cover.   gear.  Retro Instruments currently makes a reissue of this classic piece (but with a top cover).

Above: an inexpensive studio echo unit of the early 1960s: the Telefunken Echo Mixer. It is a spring-reverb unit.  Click this link for an audio demo.   Apparently used by Klaus Schulze on his “Irrlicht,” which is one of my favorite records.

DOWNLOAD: Lang_Audio_Electronics_catalog

Products covered, with photos and text description, include: Lang LRP-1B tape recorder electronics (for Ampex 300 generation machines), LTP-1A tape playback amp, LRA-1C record/playback amp, LMX-4 and LMX-5 broadcast consoles, LMP-1 stereo portable mixer, Record Stereo Mixer, LMX-2 mixer, LPM-2 portable mixer, PEQ-2 and PEQ-3 equalizers, Lang Sync Panel, Disc Recording Equalizer, plus many more accessories.

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Lang was known primarily for the various upgrades and support equipment that they manufactured for Ampex tape machines.  As shown above, they also offered solid-state equalizer that appear similar in function to the popular Pultec units of the era.  There are also several models of audio mixers on offer, a few of which were available as early as 1961.

Above: the Lang ‘compact’ mono mixer.  Advert circa 1961.  Looks very similar to my later stereo Gately mixing system , which I spent $250 and several hours on…and i still can’t figure out what the hell i’m gonna use it for.

Above: the Lang Raecord portable stereo (of a sort…) mixer, also introduced circa 1961.    Seems pretty scarce.

Today on PS dot com: some pro audio gear from NYC’s legendary Fairchild Recording Equipment Corporation.  This post will strictly be a scan of marketing materials from the era, as I have never used or serviced any of these pieces (other than a 670 clone).   A PS Dot Com reader alerted me to the fascinating story of Sherman Fairchild, the man behind the corporation that brought the world this very advanced audio technology: you will not be surprised to learn that he had roots in the aviation industry and a key connection to IBM.  See the comments section or click here to learn more.

this gets a little lengthy so click below to READ ON…

Above: the 602 Conax and 670 limiter.

Above: the Fairchild 664 console channel equalizer.  A nice-looking example (with integral gain make-up stage!) is on eBay right now for a pretty reasonable price. The 668/669 Lumiten is an attenuator that uses a light source and LDR to regulate gain.  See the ‘Comments’ section of this post for much more information regarding the Lumiten.

Above: the Fairchild 740 lathe, 605 phono EQ, and 666/666A compressor.

Above: the Fairchild 641 stereo cutter system, 670 stereo limiter, etc..

Above: the Fairchild Integra range of console channel modules circa 1963:  For each channel on your board, you could have a 662 preamp, a 661 gate, a 664 equalizer, a 663 compressor, all controlled by a 668 noiseless Lumiten fader.  This is some incredible technology considering the era.  I gotta imagine that no intact Integra console still exists.  Anyone out there ever work on one of these?

And finally, some detail on the Conax.  Based on the description here, it seems like this piece was high-frequency compressor…aka a de-esser. 

For more Fairchild audio coverage on Preservation Sound… click this link.

Good lord take a look at this thing.  The Phillips EL 6911 echo machine.  Distributed in the US by Norelco, who also distro’d AKG mics in the 1960s.  You can find much more information on this monster at this website.  These still turn up on eBay from time to time. 

DOWNLOAD: ABCstudioEquipment

Big thanks to PS dot com reader E. Lorden.  E. lives in Australia and has provided us with extensive schematics and technical data on AWA broadcast-audio equipment.  AWA was the ‘RCA’ of Australia throughout much of the 20th century: they made and marketed both consumer and professional electronics equipment as well as engaging in actual broadcasting.  Due to a very protective import-taxation scheme in place in Australia until the early 1970s (as well as the high cost of shipping imported goods to that country), AWA was highly incentivized to develop its own unique line of broadcast audio equipment for the Australian market.  I have personally never seen any of these items myself, and many of the circuits are different than any US broadcast audio components that I am aware of; perhaps there is more of a Telefunken heritage to this kit.  Or perhaps it’s genuinely just unique.  Anyhow, plenty to dig into… limiters, mic preamps, power amps, etc…  Although the document is dated 1967, the circuits covered extend well back to the 1940s, judging by the types of ‘valves’ employed.

All photos in this post credited to E. Lorden

NOTE: the above unit eventually did sell on eBay for $35,000.  See below for scan…

Here’s something that you don’t see everyday.  Courtesy of this eBay auction, an apparently original EMI-modified Altec 436B.  Buy it now for $55,000 (fifty-five-thousand) US dollars.   If this price seems absurd (and it surely is optimistic at best),  I will point out that the seller claims (and he/she may very well  be correct) that this particular unit was in fact used on numerous Beatles recordings.  The particular quality of its compression, pumping, and mild distortion were integral to creating the vocal and drum sounds of the most widely-heard and widely-copied pop/rock recorded sounds in the entire history of sound recording.   Add to that likely provenance the fact that only a handful of these units were ever made and you have a very unique piece of audio history on the block.

image source

Here’s a shot of the rear of the unit.  A few things worth noting: the JJ multicap (above the blue LCR cap) is of recent manufacture, indicating recent servicing.  The lineup of three tubes and only two audio transformers indicates that this unit began its life as a 436(x) compressor, not a 438(x) mic pre/compressor.  The mains transformer (far left) was necessarily replaced to facilitate easier use in a 220v country.  My biggest question (and please, readers, fill me in… ) is:  what is that unit above the 6AL5 tube?  Is it a 2nd output transformer to allow of use of a T-pad attenuator on the output while retaining output balance (IE., the T-pad would go between the two transformers)?

image source

Getting back to the front panel, we see evidence of the modifications that EMI made in order to make the 436B more useful in the studio.  From left to right: a ‘balance’ push-button switch (not sure what this is, but i image it might have something to do with balancing the vari-mu action of the two halves of the gain-reduction tube?  not sure how a pushbutton switch would be implemented there?). Next, a ‘recovery’ or ‘release’ control (self explanatory), then factory ‘input’ attenuator control, and to the right of the meter an output attenuator.

Anyway…those of you who have been following PS dot com for a while will know that I have a tremendous interest in these Altec compressors; I have restored them, modified them, scratch-built them, and use one regularly in the studio.   Here’s some links to catch up:

History of the Altec 43(x) compressor and its relation to the EMI RS 124

Adding a balanced output attenuator to an Altec compressor

Modifying an Altec 438a compressor to gain many of the EMI RS124 features

DOWNLOAD SYNTHS:Music_Emp_Keys_1980

DOWNLOAD EFFECTS PEDALS: Music_Emp_FX_1980

DOWNLOAD PRO AUDIO: Music_Emp_audio_1980

Keyboard instruments covered, with photos, text, and (often) pricing, include: ARP Axxe, Odyssey, Quadra, Quartet, Omni II, and 2600 keyboards, Moog Micro Moog, Mini-Moog, Polymoog, and Multi-Moog, Korg MS-10 and MS-20; Oberheim OB-1, two-voice, OB-X, and four and eight-voice systems; Roland RS-09 and RS-505 string machines; Roland MP-600 electronic piano; mechanical keyboards from Hohner (pianet and clavinet) and Wurlitzer (200); Leslie 820, 860, 147, 760, and 815 rotating speaker systems.

Effects pedals include full lines from MXR (many…), Morley (VOL, SVO, PWO, WVO, PWB, PWF, PWA, PFA, and PRL), Mutron (III, Phasor II, Vol-Wah, Octave Divider, and Bi-Phase), and DOD (250, 280, 401, 640); plus interesting oddities like the Gizmotron, eBow, Altair PW-5, and the original Pignose amplifier.

Audio includes a wide range of mics from Shure, Sennheiser, Beyer, Sony, plus some predictable selections from the AKG and Electrovoice lines; Teac tape machines; Technics 1500 and RS-M85; the Tangent 3216 mixing console; time delay effects including Loft 440, Lexicon Prime Time model 93, MXR digital delay and flanger-doubler; Roland space echos, Tapco 4400 and Furman RV-1 reverbs; compressors including MXR mini, Ashly SC55 and SC-50. Biamp Quad Compressor, Ureil LA4, and DBX compressors 163, 160, 162, 165; plus a host of mainly graphic EQs including Biamp EQ210, EQ270A and EQ110R, MXR Dual 15 abd 31, Tapco C-201, Ashly SC-63 and SC-66, and Ureil 537 and 545 parametric filter set.

DOD effects pedals circa 1980

The Gizmotron, which is sort of the mechanical equivalent of an e-Bow; it was invented by Lol Creme and Kevin Godley of band 10CC; I have never come across one of these but wow would I love this for studio work.  Check out some amazing sound clips here.

The Korg MS-20.  This is our house monosynth at Gold Coast Recorders and lord do these things sound great.  Pitch to CV conversion built in!

Loft 440 Time Delay effects.  Loft was a Connecticut maker of Pro Audio kit in the 70s/80s.  Much previous Loft coverage on PS dot com; maybe start here…

I just got a new MacBook Pro and guess what.  My Protools LE 8 does not work on it.  Big surprise.  Everytime this happens (which means everytime a new Mac comes into my life…) I inch closer to replacing the PT LE system that I use for demos at home with one of these 70s four-track reel systems.  Of course, an Mbox and Laptop weigh about 100lbs less and take up 1/10th the desk space.   Is anyone out there making demos (or album masters) on a Teac/Tascam 1/4″ reel system? Drop us a line and let us know…

Technics RS-M85 cassette deck.  Beautiful looking machine.  Working example on eBay right now for $138…

The Urei LA4 was the compressor that I learned on at school.  The studio had a pair and they sounded great. Simple and effective… 

I don’t know how accurate it was to have ever called the Beyer M69 a popular microphone, but they do have a good sound.  We have a pair at GCR and they are a good alternative to the SM58 as a handheld dynamic.  To my ears they sound less boxy; seem to have less proximity effect. 

For previous Music Emporium coverage on PS dot com (incredible as it may sound….), visit here…

Here is how I took an original-spec 438A and modify it so that one could use it alongside more modern compressors in a music-production studio.

(From Left to Right): A switch to determine if either the two-stage mic preamp OR a balanced 15K nominal signal hits the input transformer of the compression amp; a threshold/ratio combo control ala the later Altec 436C; (top) an balanced output level control/pad ala the Gates Sta-Level (see here for details); (bottom) a release time control ala the Altec 436C.  The original volume pot still functions as an interstage gain control for the mic preamp.

Here’s the unit with the face flipped down, revealing the wiring to the newly added pots and switches.  At my client’s request I used 11-position detented pots; ALPHA makes these in a huge range of values and Mouser stocks them for just about $2 a piece.  A great value IMO.  I used sliver-plated 24ga stranded wire for the audio wiring and 22ga solid copper for the control signal wiring.

This 438A is now ready for use in any situation where a gentle, vintage compression sound is desired.  The input and output levels are what you would expect from a standard pro-audio compressor; the release timing is widely variable (but never very fast – this would cause some artifacts due to the way these simple vari-mu compressors function); and the threshold/ratio control will yield a wide range of results as well.  Since the unit was in good physical and electrical shape, no re-tubing or re-capping was necessary.

Continuing our review of the first two years of AUDIO magazine, today we will look at some of the more interesting bits of pro audio kit in evidence during 1954/1955.  AUDIO magazine had just made the transition to its new moniker in the wake of the introduction of the AES Journal (Audio Engineering Society), and for the moment, AUDIO sill covered a bit of the pro audio equipment that would soon largely leave its pages.

The GE BA-5 pictured above is, AFAIK, the largest and most complicated analog audio compressor ever made.  Although it has much less tubes, it’s kinda even more sophisticated than the Fairchild 660/670.    Here’s the schematic if you are interested.  From what i recall,  the BA-5 works by creating an ultra high frequency sidechain to obtain the control voltage value for the compression; I can’t recall the details at the moment but the basic concept was to allow the unit to have huge amounts of compression with very fast timings, but without any pumping or dipping artifacts.  Which was also the intent of the 660/670 design.  If anyone out there has a better explanation of this monster, please chime in.

The General Electric BA-6-B remote amplifer/mixer

The General Electric BA-9-A compressor, a much more basic pro audio compressor.  Circuit is essentially the same as the Gates Sta-Level.  The BA-9 is also known as the the uni-level; schematics are readily available online.

The General Electric BA-1-F plug-in preamp and BA-12-C plug-in power amp

The Hycor 4201 equalizer.  Similar to a Pultec program EQ but without the makeup gain amp; the Hycor is a fully passive device.

Langevin 5116 modular preamp

The full Langevin modular line of 1954: 5116 preamp, 5117 power amp, and 5206, 5208 power supplies

Another remote amp from 1954 – the Magnasync G-924.  Looks very cool.  Magnasync would soon be merged with the Moviola corporation and become a brand name for sound-for-film equipment.  See this previous post for an experiment with the Magnsync URS device.

An early ad (1955) for the Altec 604 duplex loudspeaker.  The 604 would remain a studio-standard recording/mixing monitor speaker well into the 1970s.

Okay this is getting pretty tech-y but here’s an advert announcing some new-ish tubes you might want to consider: the Tung-sol 12AX7 and the 5881 (AKA ruggedized 6L6).   Transistors were on the market at this point (1955) but were a ways off from reaching the performance and reliability that these great tubes offered.

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