Categories
Pro Audio Archive RCA

Cuttin’ Records: RCA Recording Filter and Cutting-Arm Assembly

Most days in the studio end with me making WAV or MP3 files of scratch mixes or final masters.  I will then upload, copy, or email the files to the musicians.  It takes mere moments to do this.  60 years ago the process of creating a listening copy was considerably more difficult.   The engineer would need to literally cut a record from the studio tape.  And the record was not a literal exact transcription of the tape; the input signal to the record-cutting head required considerable equalization so in order to make a record that would ‘playback’ properly on the equipment of the day.  Click on the links below to download the manuals for the RCA ‘Recording Attachment’ Type 72-D and 72-DX, aka MI-11901/MI-11900.  The ‘recording attachment’ was an assembly that would be mounted on a turntable.  It consisted of an arm, with various provisions to adjust tracking pressure and record timing, and a cutting head.  The second PDF is the manual/schematic for the ‘Recording Filter’ M1-4916-A, which was a passive fixed-equalizer that provided for the then-current ‘orthacoustic’ frequency-response characteristic.

‘Orthacoustic’ response was a pre-RIAA record compensation curve necessitated by the the intrinsic flaws of record-lacquer material and turntable-mechanics of the 1930s.  Confused yet?  Read this very informative Wiki article on the history of the (still in use in 2010) RIAA compensation curve and all will be made clear (maybe).

Here are the manuals…

RCA_MI-11901

RCA_MI-4916-A

Categories
Publications Technical

MJ Audio Technology Magazine

In a previous post, I discussed the late great American magazine Audio, published between 1947 and 2000.  Audio combined equipment reviews, listening tests, music reviews, and DIY tech into a single publication.  It’s cessation has left a great absence in the American audio-scene that the internet has luckily filled (chicken or egg?).

MJ Audio Technology magazine is the closest Japanese equivalent to Audio.   However, MJ has been in print since 1924 (!) and it is still being published.  Amazing.  Here is a brief history of MJ, taken from the DIYaudio listserve (member tiefbassuebertr):

“This magazine, founded in 1924 by Mr. Mitsugu Tomabeji, is one of the earliest and most influential radio magazines that I know. In the early years it was Radio experimenter’s magazine (Musen to Jikken = Radio and Experiments). The early publisher of this magazine was the currently brand ITO and the currently publisher now is Mr. Seibundo Shinkosha. In general this magazine is a DIYer magazine and is very technical but is full of great articles on electronics and speaker design, room acoustics, audio history, as well as reviews, news, show reports, etc.”

(Web Source)

Even if you can’t read a word of Japanese, this is a great magazine to pick up if you are interested in audio DIY at all.  Recent issues can be purchased at Kinokuniya in New York City.  I would bet that the several Kinokuniyas on the west coast stock it as well.

Here is an example of a project from the 1033rd issue.

…Here we see a beautiful build of a Single-Ended parallel stereo amp which uses the very unusual 5998 twin-triode tube.  This is a tube that I had not been aware of, as it was never intended as an audio tube by the manufacturer.  Nonetheless, MJ has based this project around it.  We are offered the tube data sheet…

A very clear and well-illustrated schematic,…

…Layout details,…

…And even chassis-fabrication guides.

Overall, the level of quality and attention-to-detail most reminds me of the old Mullard “Tube Circuits For Audio” book (also excellent).   Finally, the technical performance specs, and listening tests. These listening tests generally seem to involve the singing and/or playing of pretty-yet-demure women.

This project is given much greater detail in the magazine than I am providing here, and in fact it is only one of several on offer in this issue alone.  Check it out if you can.

Categories
Manufacturers Pro Audio Archive

Audio + Design Scamp Outboard Modules

Audio + Design (Also known as Audio & Design, or Audio and Design, or Audio Design Recording- hf. ADR) is a British firm that was responsible for the first FET-based limiter.  Their ‘Vocal Stressor’ dynamics processor has long been rumored to be the the kit limiter used on many Led Zeppelin recordings.  For readers who have not spent much time in recording studios:  John Bonham’s  drum sound on the Zeppelin records is still, 40 years later, regarded as a benchmark of rock drum sound, by both drummers and producers/engineers.  And by rock-music fans in general.  A lot of time gets spent daily in recording studios around the world trying to ‘get that Bonham sound.’  So this rumor is somewhat significant.

Other well-known users of the ADR compressors include Mike Chapman, producer of The Sweet and about a million other seminal 70’s groups.

Anyhow.  The unit featured at the head of this post is module from ADR’s ‘Scamp’ line of plug-in modular audio processing equipment.  From what I have been able to tell, various units in the Scamp line were available between at least 1976 and 1984.    Modular racks of audio processing equipment were very popular during this period.  The concept is a good one: users can purchase a single rack-case with slots that accept the manufacturer’s modules.  The Rack-Case has a built-in power supply which provides the voltage(s) that the units need in order to operate.  In this way, a single chassis/powersupply can support up to 17 pieces of processing gear, rather than each little compressor, EQ, etc., each having their own.  Since the current draw of these items is so low, it makes a lot of sense. It saves a lot of space in the studio, and it saves money.

Of the other contemporary manufacturers of modular processing set-ups,   The DBX 900 series is perhaps the most widely-seen.  Valley People, Aphex and API also made these types of product lines.   The API 500 series has survived, and in fact become a contemporary standard in recording studios, with dozens of independent firms currently making a huge variety of processing units to fit the API-500 spec frame/voltage.   I have a DBX 900 rack and an API 500 rack, and they are some of my most-often used pieces in the studio.

There is a lot of documentation on the web regarding the DBX 900 series and the API 500 line.  The ADR Scamp line-up is not as well-represented.  Click on the link below to download 18-pages of 1976-1984 SCAMP paper.

DOWNLOAD:

AudioAndDesignScamp1984

Categories
Synthesizers

Yamaha Electronic Keyboard Lineup Circa 1980

The first in a 3-month series of scans of obscure audio paper:  the entire Yamaha Keyboard line from approx.  1980 (no date indicated in the catalog itself).  Yamaha made some great analog keyboards – i currently have a CS-1 and it is very cool – and there earlier ‘YC’ combo organ series are very underrated.  “The Peavey of Japan,” it has been said.  Dig in….

Download the entire 12-page catalog (6 megs):

YamahaKeysC1980

Categories
Uncategorized

Under Construction. Call For Archival Requests.

Tomorrow marks the first day of what we expect to be a 3-month period of intense construction work to create a new recording studio-space here in historic Bridgeport CT.

Since this process will have me very… occupied, I am going to take the opportunity to focus this site for the next three months on my collection of catalogs, manuals, schematics, and product sheets relating to older+antique audio.  Everyday I will post full scans of a new document hitherto unavailable on the WWW.  Expect some very interesting and very unusual stuff, with daily updates.

If anyone out there has any requests for scans from a certain manufacturer, product, or product type, just drop me a line and if I have it (and it’s not already on the web), I will scan and post it.

During this 3-month period I will continue to write posts similar to the existing content, but these will come on more a weekly basis rather than daily.

Starting in February I will resume the daily-updates of the more broad nature that is the goal of this website.

Categories
Uncategorized

Shour. It’s Your Sound.

I wrote briefly about Cairo Egypt in an earlier post. As usually happens on our vacations, I try to seek out whatever regional audio-oddities I can.  Cairo did not offer much in this regard, but I managed to find a few items of interest.

Most of what I came across was public-address equipment and rudimentary recording gear.  This caught my eye in a shop beneath a highway overpass in the center of the city.

It was a new microphone in a shopworn box.  It cost me about $15.  Meet the Shour Beta 57.

Look familiar?  Yes it does.  Today we will take a listen to this marvel of copyright infringement and see how it compares to it’s Shure-brand inspiration.

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When is an object a copy?  What defines a fake versus an imitation?  Deception, or the desire to deceive, is certainly a factor.  I think that our friends as Shour INC probably had deception in mind, especially since Roman characters are likely as inscrutable to most Egyptian residents as Arabic is to me.

There is no Shour dot com, btw.  And there is absolutely nothing on Google relating to Shour Microphones.  It’s not a bad attempt at a name, though.  Sort of suggests ‘Shure’ (the world’s best-known microphone manufacturer) and ‘Shout’ (the most basic of spoken signals) combined into one convenient brand.

I think the fact that they actually go so far as to tout (highly doubtful) Mexican manufacture (as actual Shure mics are made in Mexico) is pretty telling. I am going to assume that the Shour was birthed in China, but I have no way of knowing.  Oh and no word on the availability of the rest of the Shour line.  OK!  On to the sound.

I did not have a Shure Beta 57 in the house today, so I used a regular Shure SM57, which I imagine sounds pretty similar…  I think the polar pattern rather than frequency response is more of a factor in distinguishing an SM 57 from a Shure Beta 57 (Cardiod vs Hypercardiod).

Despite having an XLR-M output jack, the Shour is a high-Z, unbalanced mic.  Connecting it to the DI input of the MBOX and cranking the gain resulted in audible digital inteference noise (sounded similar to iPhone interference), so in order to nullify this, I instead used a direct-box inline.  This DI is one of my own, from a series that I built using 1970’s AKG UT-330 matching transformers.

OK here’s the sound clips.  Have a listen.  First, the SM57.

Shure_SM57

…and now the Shour (through the Direct-Inject box):

Shour_Beta_57A

A few things are obvious:  The Shure 57 has much better low-end response evident, even with the signal being an acoustic guitar mic’d at 2-feet.  I would imagine that if you stuck these mics on a bass guitar amp or floor tom, the difference would be much more dramatic.  On the other hand, this could be due to the Direct Inject box, and not the mic itself.  I have never measured the response of this DI box.

The other clear difference is the noise level.  Since I am using the DI box, I needed to boost the gain on the Shour input to 100%.  Anyone who has used an M-Box will know that this basically creates a White-Noise-Generator.  Those preamps are terrible.

Overall, though, the basic sound is similar.  I was surprised.  Of course, there are a whole wealth of other characteristics that distinguish microphone quality, such as feedback resistance, durability, and SPL handling ability, but I think it’s safe to say that I got my full $15 worth of microphone here.

Anyone have a similar knock-off mic story?

Categories
Pro Audio Archive Publications

Mixing in the 70’s – UPDATE 2 -Philips Console Information

Philips Mixing Console c. 1974

Since we originally published this post in 2010, several folks have written in to provide more information about these desks.

Update 1:

Tom H. in Sweden sent in a picture of his Philips MD console.

From Tom:

“I got it from NYC… Had to recap it and go thru it… Sounds fab.
Germanium Transistor based, and sounds very nice to me… It’s quite limited but the sound makes up for it…  12/4 configuration, one Aux send, no pans! Left/Center/Right by switches…  4 EQ’s w/ 10K, 100Hz boost or cut + presence boost available on tracks 5-12…   I use external valve mixers and micpres,  basically I use it with my Studer A80 1″ 8-track, mixing to a Studer C37 1/4″ machine.”

Update 2:

Above: courtesy of PS Dot Com reader M.G. in Canada comes this document from 1968 which outlines all of the part numbers for the Philips console components.  MG writes: “I came very close to buying a Philips “Control Desk” in April 1968… (this) is the quotation I received at the time listing all the Philips part numbers…

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No big theme today.  Instead: a quick look at some 1970’s mixing consoles that caught my eye for one reason or another.  Dig in, and let us know if you have any thoughts on working with these various oddities.

I cannot find any information on Wiegand Consoles.  Looks to be serious kit though.  A quick google search puts Midas at the head of the results, no reason indicated: perhaps Wiegand is part of the early Midas story?  Anyone?

Schlumberger consoles seems to have generated some heated discussion on the G*****tz forum not so long ago.  No one could agree where they were built.  Germany or France?   Probably not too common in the USA.

Style for miles.  Philips MD mixing console.  Sign me up.

From the pages of the AES journal, an early appearance of ‘pro-sumer’ ‘home-recording’ kit.  I recently purchased a near-mint TASCAM Model 5 EX expander unit for a few bucks at a yard sale (Not yr average yard sale: I also picked up a few P+G faders, VU meter, sequential tone generator, and a mile of balanced belden cable).

(web source)

The Model 5 EX is basically 12-channels of Model 5 minus the meters, buss masters, and stereo master.  So you’ve got 12 inputs (mic inputs have Tamura transformers!) with 4 unbalanced buss outputs plus 2 aux sends.  It certainly would be possible to create a stereo mix on the model 5 EX, but the intent was to use it with a model 5.  Right now, my Model 5 EX is sitting in the shop awaiting the axe.  Eventually I will start to explore ‘upgrading’ the channel cards in the hope of eventually making some channel strips worth racking + selling.  The channels don’t sound terrible as-is, but they are more noisy than i would like.  As-in broadband white noise.

…And the more ‘pro’ TASCAM board of the era.  The TASCAM Model 10.

Speaking of ‘mixing’ on a 4-buss unit with no master… I have always been very curious about these little Gately mixers.   Hope to get my hands on one soon..

Langevin Engineer John Jarvis describes his methodology for console design in this 1969 AES article.  Jarvis left Langevin for UREI shortly after this piece was written.

(web source)

Here is a photo of an actual unit.  These are super-cool.  If I ever have a spare year I would love to DIY one of these from scratch.

Interface Electronics model 300.  Anyone?

…And the one that became a keeper; a classic.  The API 2488.  Dan Alexander has a great wealth of information on this piece.  Check out his fantastic website sometime.

Categories
Pro Audio Archive Publications

American Consoles of 1978

Following that review of SONY’s PCM-1, on a less technical note: some ‘eye-candy’ from 1978.  New consoles from Quad/Eight, Harrison, Spectra-Sonics, and Sound Workshop.

Categories
Publications

AES Journals of 1978: Digital Audio meets VCR

Looking through a selection of Audio Engineering Society journals from 1978, we see several themes repeated.  Primarily: digital signal processing (echo and primitive digital reverb) and digital recording.  Papers dedicated to various issues concerning digital encoding and playback occupy many of these pages.  Digital audio recording was a long way from being widely-accepted as professional practice in 1978, but based on the content of these publications, most in the field seem to have regarded it as inevitable.  Most of the content of these issues is excruciating technical, and well beyond the scope of this website; one paper, though, brought light to a forgotten early chapter in the digital audio story.

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When I first became involved with music recording in the early 1990s,  I often heard vague stories of guys ‘recording digital audio onto VCRs.’   The September 1978 issue of the AES journal finally clarified this all for me.  As it turns out, SONY was the first company to bring a digital-audio-recording product to mass-market.

(web source)

SONY’s PCM-1 (read an excellent period analysis here) was not a digital audio recorder, per se; rather, it was an early D/A and A/D converter which was used in conjunction with an analog video recorder as the data storage device.

Basically, the PCM-1 converted analog audio to a digital data stream, and then converted this digital stream into a video signal by adding video synchronization data to the digital audio stream.  SONY’s engineers chose 44.05k / 16bit as their data spec.  This is very close to our modern standard of 44.1 / 16 bit.  Not sure why the slight difference.  Anyone?

Interesting stuff.  A quick web search does not reveal any PCM-1s on the market; I wonder how many were sold in the US.

Anyone use a PCM-1 or any of the later models? Any thoughts?

Is the digital audio signal from these SONY devices compatible with modern digital audio streams such as AES/EBU or spdif?

Categories
Early Electronic Music History Synthesizers

Early Electronic Music Technology: Part One

From the back-pages of the AES Journal in 1965:

Moog is a legendary name in the world of music.  As far as manufacturers/innovators of musical/audio equipment go, Robert Moog is a close to a household name as anyone I can think of.  The original Moog Modular Synthesizer, as used in early ‘hit’ electronic records such as Carlos’ “Switched on Bach,” was the earliest commercially-available integrated audio synthesizer instrument.

But as much as Moog was indeed an innovator and a massive contributor to the world of music and audio, widespread acceptance of his (and others – Buchla, EMS, etc) synthesizer systems actually marked the demise of a much earlier tradition of electronic music practice.  Because the Moog Modular, complex and inscrutable as it now seems, was in fact a massive simplification and streamlining of the earlier academic/institutional ad-hoc electronic music studio.   Today we will start (what I intend to be) a series of investigations into the technology of early studios used by electronic pioneers such as Varese, Stockhausen, and Luening.



I am slowly-but-surely accumulating some of the original circa 1960 equipment similar to that which pre-Moog electronic music was created with, and I hope to attempt some of this early practice myself.

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This article, from the same 1965 issue of the AES journal which heralded the arrival of ‘The Moog,” details a basic ad-hoc electronic studio of the era.  Read through it.  The basic components that Robert Moog integrated into his ‘modular instrument’ are all present in the Brandeis studio, minus the keyboard: oscillators, a mixer, a filter, a noise generator, a ring modulator, a spring reverb unit.  And, of course, several tape-recorders to allow the various sounds to be layered and combined in order to meet the composer’s intent.  In order to understand just how much effort was necessary to create even these basic conditions for composing, consider this:  the (very simple) mixer had to be custom-designed and built by an engineering firm.

And the studio-staff themselves designed and built the white-noise generator that the set-up used.

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Columbia University had a similar, but much more sophisticated studio at the time.  They began the construction of their set-up in 1952, nine years before Brandeis did the same.

Here the Columbia/Princeton studio is profiled in the June 1965 issue of ‘Radio Electronics,’ the same year that  the AES covered Brandeis.

You can here some of the music that Otto Luening made on this rig (presumably) at the youtube link earlier in my article.  I find it to be very beautiful; it is in many ways the most basic type of music: I think we experience it directly as ‘Organized Noise,’ as free-as-possible from cliche and expectation.  Just my $.02.

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As I had mentioned earlier, Moog’s real innovation was to take all of the disparate components of electronic sound-generation – the oscillators, mixer, filters, noise generator, ring modulator, a spring reverb  – and combine them into little panels that fit a single chassis, with a conventional piano-type keyboard as the primary input-control device.

But where did our pre-Moog pioneers source their hardware?  As the c. 1965 coverage indicates, Brandeis and Columbia had some of it custom built; some was built by the staff; and some originated as non-musical laboratory equipment.

General Radio was perhaps the pre-eminent manufacturer of electronic test equipment in the 1950s and 1960s.  I have owned some of their pieces, and the build-quality is absolutely incredible.

This type of hardware is fairly easily obtained nowadways for very little money – i generally pay $5 – $20 for a unit – and usually it still works.  Sometimes it is hard to resist the temptation to chop up these pieces in order to use the valuable transformers for other projects, but I have saved a few of the better pieces in the hopes of getting my own super-primitive Electronic Composing Studio together.

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Anyone out there ever made music on a pre-Moog system?

Anyone attend the Brandeis or Columbia programs in the early 1960’s?  Drop a line and let know about it.