Categories
Altec Pro Audio Archive

Pro Audio hardware of the early 1950s

The General Electric (GE) BA-5-A Limiter

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.

Categories
Microphones

Studio Microphones of 1955

The Altec 639, 633, 670A, 660, 671A, 632C, M-20, and M-11 microphones

From the pages of AUDIO magazine in 1954/55: new and new-ish studio microphones at the dawn of the transistor age.  Check em out…

The Shure 530.  This was Shure’s mid-range ‘pencil’ mic in the 1950s.  At the top end was the 525; lower in the line was the 535.  See this link for some audio tests including the 535.

Reslo and Bang & Olufsen ribbon microphones were marketed and distributed in the USA under the ‘Fentone’ banner in the 1950s.  Fentone continued as a brand-name for microphone marketing into the 1960s, but later Fentone product was not of this quality.

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Above is the two-page advertising spread that introduced the Electrovoice 666 to the world.  The 666 is the grandfather of the much-beloved Electrovoice Re20, which has been a favorite of recording and live-sound engineers for decades.  Like the Sennhesier 421, the RE-20 is somewhat proof that dynamic microphone technology hasn’t really advanced much in the past three decades.

 

 

 

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Above, a 1955 advert for the 666 along with a review of the 666 from AUDIO magazine.

Above is a 1955 ad for the Electrovoice 664.  The 664 was the ‘public address’ aka ‘cheaper’ version of the 666; the 664 was immensely popular and thousands remain today.  If you come across one of these, there is a good chance it will still work fine.  In terms of visual recognition,  I would argue the 664 has an iconic appeal exceeded only by the Shure 55 series and the RCA 77 and 44 series.  The 664 is not a terrible sounding microphone, although i don’t recommend actually using it in a modern high-decibel PA system.

Wrapping up, here’s an ad for all the microphones that Electrovoice considered its ‘professional quality’ in 1955: the 666, lesser-variant 665, 655, its lesser variant 654, 646 lavalier, 650 and 535.    Hear my pair of ancient 655s in-action here…

Categories
Magnecord Pro Audio Archive

Magnecord Complete Line Catalog Circa 1953

From the personal archive of John Boyers, founding partner of Magnecord INC, we present the complete circa 1953 Magnecord INC catalog. Click the link below to download the eight-page PDF:

DOWNLOAD: Magnecord_Catalog_Circa1953

Products covered, with text and photos, include: Magnecord PT6-A Recorder Mechanism, PT6-R line-level input amplifier and PT6-J Mic-level input/output amplifier; PT63-A three-head recorder and companion PT63-J amplifier; the full line of PT6-series accessories, including the PT6-HT ‘turnover’ panel, PT6-IM3 and PT6-IM4 microphone-level input mixers, PT6-M ten-inch reel adapter mechanism, PT6-EL continuous loop panel (really confused as to how on earth this thing works).  Also includes the Magnecord PT7-A, PT7-M, PT7-C series of recorders/amplifiers, which offered slightly improved audio specs relative to the PT-6 series.

Click the ‘Magnecord’ link in the right-hand ‘Categories’ column of the homepage to see much more Magnecord coverage on PS dot com.

 

Categories
Microphones Pro Audio Archive

Studio Microphones of 1954

AKG D36 advert from 1954

Continuing our survey of AUDIO magazine’s early years: over the next couple of weeks we will look at some of the more relevant content from the first two years that this venerable publication ran under the title ‘Audio,’ the prior title having been ‘Audio Engineering.’ (full backstory here and here).  We’ll start today with the crop of studio microphones on the market in 1954.  One thing becomes pretty clear: the Austrians were really ahead of their time.AKG C-12 advert 1954

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Telefunken U-47 and 201-M adverts 1954

Capps CM 2001, 2030, 2250, and DM 2050 microphones c. 1954.

Anyone have any experience with these mics?  Look interesting.  Let us know…

The Reeves S-T Condenser Microphone; another early American Condenser mic. Very rare.

The Shure 333 ribbon mic.  This was their cardiod ribbon.  I’ve never used one of these, but i would love to get my hands on one.  Stephen Sank recently re-ribboned my circa 1954 Shure 300 (the 300 was Shure’s high-end figure-8 ribbon of the same period) and wow did he do a great job.  It sounds incredible now.    I had thought it was a P.O.S. until he re-did it.  If you own a vintage Shure ribbon mic and you are underwhelmed by it. give Sank a call and see what he can do for you.

…and here is some period analysis of the then-new Shure 333.

Follow the link below to READ-ON….  more studio mics of ’54 follow….

Continue reading “Studio Microphones of 1954”

Categories
Guitar Equipment Pro Audio Archive

Vintage Marshall Archive Material Part 2: 1974

Download the complete sixteen-page 1974 Marshall Amplification catalog:

DOWNLOAD: Marshall_1974_Cat

Products covered, with text, specs, and photos, include: Marshall 1959, 1987, 1989, 1992, 2048, 2068, and 1986 tube heads; 1960, 1982, 1990, 2049, 2045, 2069, and 1935 speaker cabinets; Marshall 2064, 2065, and 2052 ‘powercel’ cabinets; Marshall 2040, 2078, and 2077 combo amps; Marshall Disco Unit (yup…) 1993 ‘turntable control unit’; Marshall 2071, 2050, and 2070 mixers; plus a slew of additional P.A. equipment.

I spent yesterday doing the final wiring and installation of my newly-restored Wheatstone SP-6 console into the control room at Gold Coast Recorders.  Took the opportunity to listen to a pile of records that I had not gotten around to.  “The Welsh Connection” by Man really caught my ear, and got me into a real UK Rock circa ’75 kinda mood.  Hence today’s post.

The most interesting bits to the ’74 Marshall Catalog are the 2050 and 2070 mixers, neither of which seem to have survived the 1970s. I cannot find a single reference to them on the web, other than in a book about Marshall.

The much smaller # 2071 mini-mixer remains in evidence; here’s a link to one for sale for a few bucks in Ireland.   A unit cosmetically similar to the 2050 is also available in England right now; price is quite good IMO…

And of course, let’s not forget the Marshall Disco Unit.

Jim Marshall offers some sage advice here as well:

This really is true.  Do not try to Disco alone.  Sad at best.

Finally, we meet the face of Marshall:

Oh that’s the wrong pic.

Here he is:

Follow this link for previous vintage Marshall coverage on PS dot com.

 

 

Categories
Uncategorized

British Broadcast Tape Recorder Circa 1935: The Marconi-Stille

The development of magnetic tape recording is generally credited to German scientists.  It is their Magnetophone that provided the inspiration for the Ampex recorder, which was the first truly high-fidelity tape machine.  From Wikipedia:

Early magnetic tape recorders were created by replacing the steel wire of a wire recorder with a thin steel tape. The first of these modified wire recorders was the Blattnerphone, created in 1929 or 1930 by the Ludwig Blattner Picture Corporation. The first practical tape recorder from AEG was the Magnetophon K1, demonstrated in Germany in 1935.

Although lesser-known,  the British Broadcast industry had a similar machine in use in that same decade.  The following account is given in the May 1954 issue of “Audio.”

Categories
Magnecord

Magnecord, INC, company history from John Boyers, Founding Partner

D. Boyers, son of Magnecord, INC founding engineer John Boyers, has once again presented Preservation Sound with an incredible collection of rare documents from this seminal pro audio manufacturer.  (click here to read the previous installment)

Over the next few weeks I will work on getting all the material online.  To start things off, here’s a written history of the Magnecord organization as related by J. Boyers in 1980.  Boyers discussed the company’s early products leading up to the introduction of the PT-6 tape machine and the PT-63 binaural (aka Stereo) tape machine.  Fascinating to learn how much trial and error was involved in these pioneering efforts.  Enjoy –

Click the link below to READ ON….

Continue reading “Magnecord, INC, company history from John Boyers, Founding Partner”
Categories
Pro Audio Archive

Audio Engineering Magazine Pt 6: audio equipment

The earliest advertisement for the Magnecorder tape machine that I have seen. BTW get ready for a large collection of original Magnecord, INC documents from one of the company founders: on this site: soon.

In the sixth and final installment of this survey of pro audio of the 1940s, as related through the pages of Audio Engineering magazine, we’ll look at some of the more interesting pieces of equipment on offer.

1948: Altec announces the 604 duplex loudspeaker. The 604 would become a staple in recording studios well into the 1970s.

…and Ampex announces the tape recorder that would change the world.  in 1948 it offered performance that would not be outdated until the 1980s.

The Arlington EA-2 ‘Audio Compensator,’ an early active EQ.  Well, maybe ‘active’ is the wrong word, but unlike other equalizers of the era, it functioned without insertion loss.  I would love to see the schematic for this unit if anyone has one to send over…

The Presto 41A limiter and 89A amplifier.  These units were intended for master-disc cutting.

RCA jacks, panels, stands, and racks of the late 1940s.

OK this scan really sucks but I was excited to find an ad for my beloved BA-2 preamp.  My advice: buy a UTC A25 on eBay and build a BA-2.  Simple and excellent.




Categories
Western Electric

Western Electric in the late 40s: Audio Engineering Mag pt. 5

The Western Electric 755A speaker

In a previous post, we looked at some early Western Electric cinema-sound equipment and the cult that surrounds this early kit.  Here’s a series of print ads from 1948 that describe some of the last-ever pro audio offerings from Western Electric.  WE was soon to be broken up by the government, and many of these products would then re-surface as Altec-branded components.

The Western Electric 756A speaker


The Western Electric 25B mixing console

The Western Electric 141, 142, and 143 audio amplifiers

The Western Electric speaker line up, featuring the 757A

 

Categories
Technical

Audio Engineering Magazine Pt 4: Schematics

Today we’ll look at some of the more interesting audio-circuit plans and schematics from the first two years of Audio Engineering magazine.  Pictured above is a great lil’ amplifer (approx. 30watts) that uses a single 6AS7G tube for push-pull output. I’ve never used these tubes, but they are real cheap.  Apparently they are sorta like 2 2A3 triodes in one envelope.  Except that they cost $13, rather than $200 for a vintage 2A3.

A fully-balanced 30-watt amp using about a million dollars in tubes.

another 30-watt amp, this time using the very cheap 807 tubes.  The 807 is similar to a 6L6, except that the grid connection is on a top cap.  807s can also handle crazy high voltage.a

A schematic for the venerable Langevin 108C, which was apparently a very popular choice for industrial audio distribution in the ’40s.

Another 807-based amp; this one is an RCA Radiotron model 515.  This looks like a great circuit.  Wish I had kept those 807s i found last year…