Categories
Guitar Equipment Technical

Magnasync Moviola URS as a guitar amp – UPDATE

Magnasync/Moviola was a Los-Angeles based manufacturer of film editing equipment.  They did make a few audio products designed to support the large upright and flatbed Moviola film-editing machines which were their main products.   The most common of these audio-products is the URS 5-watt tube amplifier with built in 4″ AlNiCo speaker.  The URS apparently debuted sometime around 1955.

I recently purchased a pair of these things for a few bucks.  Aside from needing new pilot bulbs and some contact cleaner in the volume pot, they seemed to be working alright.

The rear of the unit (not shown) has a 1/4″ speaker jack (labeled ‘Headphones” which mutes the built in speaker when a cable is inserted.  Other than that, though, there was no obvious input jack.  There is a 4-pin amphenol jack with DC present on 3 of the pins.  the 4th pin is the audio input. Ahh Ok.    There is a also a single-pin DC power connector/takeoff?  Not sure.

Anyhow, kinda irrelevant.  Since no one is going to be using these things with an actual Moviola sound-head, figured I would just make em into lil guitar amps. OK it’s gonna get a little technical here, so pls skip the next paragraph if you wanna just get to the sounds…

Since the tube compliment is 7025 (aka 12AX7) – into 6AQ5 power tube (aka basically lower-voltage rated, small-bottle 6V6) with a single volume pot between the two 7025 stages, this thing is basically…. a tweed fender champ.  Yes, there are some important differences – different plate resistor values, no cathode bypass caps on the preamp stages, and i think some frequency compensation in a the feedback loop?  But basically a tweed champ.  ANYhow…  Following the advice offered here, i put a 1/4″ guitar jack where the single-pin power socket had been.    Then i simply added the other basic components of a Fender guitar-input-stage:  a 1m resistor to ground, and a 68k resistor between the input and the grid of the input tube stage.  Replaced the 2-wire AC cable with a 3-wire grounded cable, and done.

There is plenty of talk on the web about these things…  lotsa folks have converted these to guitar amps in the same manner that i discussed… and people seem to be very happy with them.    Check out this fellow’s work. He did an especially thorough job.  I was personally kinda shocked with the sound that it makes.  Never in my life have i heard so much distortion and fuzz out of an amp.  It really is, pardon my language, fucking insane. Here’s 3 sound clips.  (Gibson Firebird gtr.   SM57 3″ in front of the speaker, into MBox.  ‘Clean’ and ‘Overdrive’ examples have analog echo pedal between the guitar and the amp.  Fuzz is just the amp.  No other eq or processing applied).  Check it…

Clean: Magnasync_URS_clean

Overdrive, fingerpicked: Magnasync_URS_overdriven

Fuzzed out (max volume): Magnasync_URS_fuzz

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UPDATE:  One of the two URS conversions that I built was purchased by producer P.K.  for use on an album project with a new band out of London.  When the record comes out (assuming the URS tracks make the final mix), I’ll post links to the cuts here so that y’all can hear the sound of these fantastic little amps in-context.

Oh and about that other URS conversion that I built: as of today, it is still on-sale at Main Drag Music in Brooklyn NY for a mere $250.  Call or email them if yr interested.

 

 

Categories
Custom Fabrication Technical

Recent Custom-Build Stereo Amplifier (Home Use)

Above: a very minimal single-ended stereo amplifier with very low gain, designed to accept headphone-level input from an iPod or Laptop and drive a pair of loudspeakers.

The circuit design is extremely simple – Each 1/2 of a 6SN7 feeds the grid of a 6L6 through a .1uf capacitor.  There is a 3-stage power supply with a choke filter before the B+ hits the output transformer.   I have built a couple dozen of these, and the design works well – the sound is very clean and direct; the small 8w output transformers do roll off the very low end, but I have never found this to be an issue with the music that I listen to.   Easy to add a powered sub to the system if one was into rap or heavy orchestral music. BTW, I use this very same circuit, with the same components, for music listening at home; I have mine connected to the output of an Airport Express, powering a pair of Bose 201 speakers. For instances when customers have wanted to hook the unit up to a line-level (rather than headphone-level) output, I substitute a 6SL7 for the 6SN7.  This requires simply changing the cathode resistors on the input tube socket and gives 3x the voltage gain.

What interests me in this design is not the mundane circuit – it is the overall appearance/sculptural aspect of the unit.  I arrived at this particular form through consideration of the appearance of the vacuum tube; as much as possible, I have tried to make the overall complete unit an amplified echo of the tube itself.  The circuit is laid out extremely carefully and the components/wires color-coded (red for B+, orange for audio), green for grounds); it’s my perhaps naive hope that someone unfamiliar with audio circuits could look at/into this piece and maybe gain some understanding of the way that a tube audio amplifier works.

Categories
Uncategorized

Lafayette Microphones of the 1960s

Do any of the Top-Quality mics in the above scan look familiar?

I seem to see… an RCA BK-1A?

….a shure 777 crystal mic?

an Electrovoice 664?

…and what is this thing exactly?

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I picked up this Lafayette PA-46 for a few dollars at the Flea Market yesterday.  It appeared to be unused; the odd 3-pin socket was unsoldered.  I hooked it up and it works well.  I wired it ‘hi-z’ and the sound is good for a 50 year old dynamic mic. The design seems to be an ‘homage’ to the contemporary Electrovoice 636.  Here they are side-by-side:

…although it also seems to have connection to the earlier Altec 21b ‘coke bottle’ condensor mic:

(image source)

…and maybe the Dukane 95D as well.

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Lafayette Electronics was an importer and retailer of consumer-electronics active from the mid 1920s through the early 1980s.  They were a competitor of Radio Shack and Allied electronics; when those two retail giants merged, Lafayette was squeezed out of the market.  So what happened to all of the Lafayette shops?  Turns out that may of them became Circuit Cities.  Crazy.  Anyhow, a lot of Lafayette’s merchandise in the 1960s was re-branded Japanese goods that bore a certain resemblance to US-made goods of the period.  These microphones are a good example.  When the Japanese designers got the ‘copy’ exactly right, it’s not that interesting…  but the odd pastiches, such as the PA-46, have a certain weird-dream charm to them.   Check out the complete history of Lafayette at this link.

Categories
Magnecord

Complete Magnecord System on eBay

For all the PS dot com readers who have inquired about the Magnecord tube reel-to-reel machines that I have discussed here: a complete system, including the very rare PT6-IM3 mixer unit, is available on eBay right now with a current price of $124.  I have no knowledge of this specific unit or this seller.    Check it out….

Categories
Pro Audio Archive Synthesizers

Vintage Moogs in Deutscher Sprache

From the PS dot com archive/pile:  Download nine pages of German-language Mini Moog and Moog Sonic-Six catalogs from 1974.

DOWNLOAD: Moog_Germany_1974

Also includes Moog German price-list of the era.

The Mini-Moog synthesizer was introduced in 1970.  It was a truly revolutionary device.

Keyboardist Rick Wakeman says of the Minimoog’s invention: “For the first time you could go on [stage] and give the guitarist a run for his money…a guitarist would say, ‘Oh shit, he’s got a Minimoog’, so they’re looking for eleven on their volume control – it’s the only way they can compete.” Wakeman said the instrument “absolutely changed the face of music.”

(Source)

Essentially, the Mini Moog was the first widely-available ‘performance’ rather than ‘studio’ synthesizer instrument.  The distinctive sound of the Mini Moog is due its 3 available oscillators (most vintage analog monophonic synths have no more than 2) and its 24db per octave filter (in contrast to the less-aggressive 18db per octave filter of its contemporaries).

The Moog Sonic-Six was similar to the Mini Moog, but it has only two oscillators.  Its ‘institutional’ design and built-in amplified speaker highlights its intent as an educational instrument.

 

Categories
Publications

Book Report: The Ultimate HiFi & Listening Rooms

Wow would you take a look at that pile.

Been thinking about Japan a lot lately; it’s impossible not to, what with the coverage of the horrific events suffered there by so many.   As I type this, NPR is reporting that the official death toll has just passed 10,000.   I attended a public magnet school for 10th grade in which I was taught Japanese and then sent to Japan to live with a suburban family for a month.  This experience had a profound effect on me and I am consequently one of many Americans who has a great fascination with, and affection for, Japan.  It is notable that middle-aged Japanese men seem by all accounts to be the world’s leading demographic of vintage-audio fans and collectors; antique audio has become my obsession as well.  Not sure how the chicken/egg thing sorts out on this one but there you go.

“The Ultimate HiFi & Listening Rooms” was published sometime in the past decade.  From what I can divine from the wholly Japanese text, it seems to be a collection of “Show us your system!” reader-submissions as published from 1989- 2002 in MJ Audio Technology, the venerable Japanese magazine.  See this earlier post for full details on MJ.

If there is one thing that collectors of obscure items all enjoy, it’s seeing the similar collections of others, and this book does not disappoint.  I picked this up in Tokyo several years back, and I have no idea if it is still in publication; if it is, Kinokuniya can certainly import it for you (The ISBN 10 is: 4-416-10201-1).

Here are some examples of the wonders on display in this 192pp volume.

I really dig how the inclusion of the antique-industrial-electronics within an otherwise conservative, posh-masculine domestic space creates a real Matthew Barney vibe.  Or, in a different sense, it feels like the discourse established by the obelisks in the various images within the Led Zep ‘Presence’ sleeve.

Aside from the strange and sizeable systems, many of the spaces themselves are quite  beautiful and idiosyncratic.

Portraiture of the obsessed.  Highly recommended.

See this link for previous Japanese Super-Collector coverage on PS.com

 

 

 

Categories
Publications

Musician Magazine 1976 -1999

What if I told you that there was a music magazine which featured writers including rock-lit luminaries Lester Bangs and Cameron Crowe; exceptionally strong graphic design; and coverage of the most successful mainstream and most vital ‘underground’ artists of the day; all aimed not at music fans, but at musicians themselves.  This publication was called, plainly, MUSICIAN, and it’s worth a look.   From Wikipedia:

Musician …was a monthly magazine that covered news and information about American popular music. Initially called “Music America”, it was founded in 1976 by Sam Holdsworth and Gordon Baird. (…) Subtitled “The Art, Business and Technology of Making Music,” it became known for its extended and thorough articles about the stars of rock music. “Musician” was not intended to be a fan magazine—the founders envisioned it as a publication about the musician’s craft, and as a result, it earned it the respect of people in the music business.  As Holdsworth told an interviewer in 2003, the magazine “…created a level of trust that made the musicians feel they were talking with peers.” In that same article, he noted that “Musician” was also known for finding out the little things that the average magazine did not—such as why a musician chose a particular brand of instrument, or what was the inspiration for a certain song.”

The Dead Kennedys in MUSICIAN, August 1985

I have always been struck by how much more candid musicians are when speaking to musician-oriented publications rather than the popular or music-fan press.  Old issues of Guitar Player magazine come to mind in this regard.  MUSICIAN mag offers much of the same.  The intended audience here is musicians, specifically; not recording engineers; but there is still some interesting historical bits for audio fans.  If you chance upon a pile of old issues, pick em up.   Some revealing advertising from the August 1985 issue:

The Tascam Porta 01, which was a lower-priced alternative to their 144/244/246 cassette four-track.  Note the light of God/Genius/Art streaming through the windows.

I studied composition at university, and we were taught on the Kurzwel K2500, which was a very high-end synth/sampler in 1995 (approx. $5000 loaded).  This is spare change in comparison to the Kurzweil 250 of 1985 (pictured above), which sold for$14,000 – $16,000.  That’s THIRTY ONE THOUSAND DOLLARS in today’s money.  Good lord.

We’ve looked at a lot of 1960s and 1970s  Sennhesier 421 ads on this site; here is an 80’s iteration, complete with the ‘blackfire’ 441 of the era.

There is a lot of emphasis in the advertising on ‘professional,’ ‘career,’ ‘making it happen,’ etc.  Not sure if we can read this as an appearance of the unavoidable-in-the-1980’s ‘yuppie’ zeitgeist but it certainly stands out today as odd language to find in a musician (artist) space, which we generally populate with romantic ‘creative’ and ‘expressive’ concepts.

Categories
Pro Audio Archive

Sound Workshop Reverbs of the 1980s

Download the four-page catalog for the Sound Workshop 242C and 262 stereo reverberation devices:

DOWNLOAD: SoundworkshopReverbs

I’ve been using a 242C in the studio for years; it’s ok for signals that don’t need much high or low end.  It’s pretty boing-y and a little bit noisy.  It does have a cool dense, gritty texture that give backing vocals a nice old-school character.  At this point, i have learned to always use it in the following way:  usually I pre-delay the input 10 or 20 ms; then run the input signal through a gentle compressor (usually DBX 160); and cut the highs and lows on the return to remove hiss and hum that the spring pickups introduce.  Oh yeah and the 242C is not really intended for +4 studio use; so i also use a Peavey stereo +4/-10 converter in order to best gain-stage it.   So yeah… a lot of support equipment around this humble box.   It does get a lot of use tho.  Hey at least it has overload LEDs and and a very-useful ‘input mix’ switch with combines both inputs – great for creating pseudo-stereo from a mono source.

Categories
Pro Audio Archive

Effectron Digital Delays Original Catalog

Download the four-page catalog for the Delta Lab Effectron line of the early 1980s:

DOWNLOAD:EffectronCatalog

If you have been following this site for a while, you will know that I dig the Effectron.  There are a  world of creative possibilities in these well-made, cheap-to-buy boxes.  Examples turn up regularly for $50 – $100.   10 minutes with one of these things will teach you more about the range of effects available using a modulated delay than you will get from a year using the plug ins.  True, there is nothing that these boxes can do that Digidesign MediumDelay can’t; but the immediate tactile response of the knobs can’t be beat.  Highly recommended.

Categories
Pro Audio Archive

Orban Audio Processors of the 1980s

Download the four-page circa 1984 Orban ‘condensed catalog’:

DOWNLOAD: OrbanCondCatalog

Photos and descriptions (no specs) of the following models: Orban 111B reverberation; 245F stereo synthesizer; 418A stereo compressor/limiter; 424A Gated compressor/limiter/De-Esser (i.e.,  ‘make-it-as-loud-as-the-FCC-will-allow’ box); 516EC 3-channel De-Esser; 526A De-esser; 622B 2-channel parametric equalizer; 672A equalizer; 674A stereo equalizer.

I have been using a 111B reverb for many years in the studio to augment the usual reverb plug-ins.  It is the best spring reverb unit I have come across.  I have found that it absolutely needs a little pre-delay applied, or else weird phase cancellation occurs when I sum the reverb output back into the board along with the direct signal.  There are may easy ways to do this, but it is worth noting.

Orban was founded three decades ago by Bob Orban.  They have always made audio equipment aimed at the radio broadcast market.  Prices for their classic 80’s gear were reasonable until recently.  Plenty of these out there, tho, so if yr patient and you will get a deal.

Since Orban is in the business of supplying broadcasters, their website have excellent technical support.  You can download the original manuals for all their products at this link on their site.