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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.

 

 

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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….

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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…

 

Categories
Microphones

American Microphones of the 1940s: Audio Engineering Magazine Pt 3.

The Amperite Velocity Microphone

Continuing our review of Audio Engineering Magazine, today we will look at some of new offerings in microphones available to audio engineers in the late 1940s.

The Electrovoice 635

The Electrovoice 650 and 645.  I really would like a nice 650… the ‘Jac Holzman Mic’

An Electrovoice line-up circa ’47The Electrovoice Cardyne and Cardax

The Electrovoice Century

The Electrovoice V1 ribbon mic.

Many more images follow.  Click the link below to Read-On…

Continue reading “American Microphones of the 1940s: Audio Engineering Magazine Pt 3.”

Categories
Publications

Audio Engineering Magazine Part 2: Cover Images 1947, 1948

Today we’ll look at some of the more interesting covers of Audio Engineering magazine from the first two years of publication.   As incredible and exotic as these interiors are, consider for a moment how similar they are in content to the cover of today’s Mix Magazine.  Get ready to enter a lost world of steel+glass….

Before audio engineers had a wide range of electronic equipment available to them (thanks to the introduction of the transistor), there was a tremendous emphasis on truly radical acoustic treatment and acoustic control devices.  Although some of the brighter minds in audio continue to achieve radical innovation in acoustics (i’m remembering sitting in Blackbird Studio C a few years ago and being totally blown away), we’ve largely abandoned complex acoustic experimentation because… well… it’s a lot cheaper and easier to buy machine made hardware/code written by outsourced programmers.  In the 1940s, you might have found that your cheapest way to improve hi-frequency response was to re-treat your entire room.  Now we might buy just buy another mic.  Or hang some pre-fab acoustic-treatment devices.

Follow the link below to see more..

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Categories
Publications

Pro Audio in the 1940s: Audio Engineering Magazine, pt 1.

Over the next few days, we’ll be taking a look at the latest-and-greatest in pro audio circa 194_, courtesy Audio Engineering magazine.  In a previous post, we looked at Audio magazine, the venerable publication which advised legions of hi-fi enthusiasts between 1954 and 2000.  As we discussed then, Audio was published as Audio Engineering for the 7 years prior, 1947 though 1953.  It was only the introduction of The Journal of the Audio Engineering Society that precipitated the name change.

The changes went well beyond the name, though.  With the AES Journal in-play, Audio shifted its focus towards hi-fi and consumer audio.  Audio Engineering had sort of split the difference between home-fi and pro audio.

I’ve selected what I felt were the most interesting and relevant bits from the first 24 issues of Audio Engineering and I will present them here as follows:  a survey of covers; professional microphones of the 1940s; interesting pro audio equipment; schematics of worthy DIY audio projects; and Western Electric ads of the era.

BTW, pictured at the top of this page: CBS radio KNX broadcast control center; an Electrovoice INC microphone test chamber; and the dubbing/rebroadcast room of WENR Chicago.  Deco-mania.

Categories
History Uncategorized

Ham Radio, Vernacular Graphics, and Silent Keys

(image source)

Have you ever been driving around and noticed one of these huge metal antennae towers erected beside a home?

(image source)

These are Ham Radio towers.  ‘Ham Radio’ is non-commercial, amateur radio-broadcasting activity which has carried on for nearly a century all over the planet.  Although by definition both amateur and non-commercial, Ham Radio is regulated by the governments of the world (including the US) and a license is required in order to participate.  The plus side of the this regulation is that, unlike, say, C.B. radios, Ham Radios can be incredibly powerful and experienced operators can (with the right equipment) directly contact other like-minded enthusiasts all over the world.  This actually sounds a lot like something else we’re familiar with…  oh right the internet.

So much can be said about this venerable institution, and I am not person to do the explaining.  So why discuss it here?  Well… most common of the signals sent with Ham Radio has always been the human voice; many Hams have, and still do, carry on the tradition of designing and building their own audio equipment; and the innovations sprung from this field have played an important role in the development of audio technologies that we all use today.  The importance of the technical aspects of signal transmission/reception in the Ham community cannot be overstated; in fact, most of he conversations that go on using this technology are in fact concerning the signal quality itself.   A direct consequence of this importance of signal integrity is that Radio Hams would often send physical postcards, in the actual mail, to those individuals with whom they had chatted with on-air.  These postcards confirmed the technical operating parameters of the radio equipment in-place when the successful conversation took place.  These are called QSL cards, and they are one of the most fascinating and exciting examples of vernacular graphic design that I am aware of.    E.  purchased a crate of several hundred at the flea market yesterday; they all date from around 1980-1987 and they are really idiosyncratic and beautiful.  Here I will present some of my favorites:

Follow the link below to continue…

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