Author: chris

Categories
Custom Fabrication

Leslie Rotating-Speaker Interface Unit – UPDATED

The Leslie Model 51 is a single-speed, large Leslie unit with 2 amps, a 15″ woofer, a rotating horn, and two stationary side-speakers.  It sounds killer, and we wanted a way to get any audio signal off the board and into the unit.  Here’s how we did it for about $100.

The Leslie 51 was originally designed to by driven and controlled by the Leslie model C2C preamplifier.  Here’s the schematic for the C2C, taken from the original manual for the 51.

The critical things to take away from this:  the 51 has a 6-pin vacuum-tube type socket which supplies input power, ground, two unbalanced audio channels (600 ohm nominal) and a control pin to turn the leslie motors on and off.  Pin one is Ground, 2 is control, 3 and 4 are 117 V AC, and 5 and 6 are the two audio channels.  The motors are turned on simply by connecting pin 2 to pin 3.  In our simplified control unit, this motor-control function is accomplished with the simple footswitch you see below.

Balanced input jacks go into Jensen JT-11-FLCF series 600/600 transformers (AKA the cheap unshielded ones).  These are used just to unbalance the lines going in, allowing the lines leading up to the interface to remain fully balanced.

The only other parts:  an IEC receptacle, a fuse holder, power switch, and the 6-pin tube socket to mate with the Leslie cable.  Enclosure is a steel Hammond.  When I fired it up, it worked fine, but there was some hum and buzz when the motor was engaged.  I figured that this was likely due to the dried-out 30 foot Leslie cable with 3 117V AC lines running parallel to the 2 unbalanced audio lines.  Even at 600 ohms that will likely cause problems.  I built a new 10-foot cable using Canare starquad for the audio lines and voila.  I made the female cable end with a 6-pin tube socket, and the male cable end from the busted-off base of a… i think it was a 42 tube.  Anyway.  Problem solved.   As beautiful as a Leslie sounds with an organ, it’s absolutely genius with guitar.  This thing does require a pretty hot level to get it up to full volume, but it’s easily within reach of any piece of +4 balanced outboard gear.   Even using it with the humble Guitar Pod sounds fantastic.

Categories
Gold Coast Recorders Uncategorized

In The Studio

Preservation Sound dot com will be less active this week because I have 7 days of back-to-back sessions booked at Gold Coast Recorders.  The first 5 days are live full-ensemble tracking and editing.  Electric string player (gtr/bass/sitar), Hammond organist, two percussionists, and one vocalist.

The Fender Super Reverb, circa 1969; perhaps the best guitar amplifier ever made; also used for bass on many of the greatest hits of the 1960s via C. Kaye.  Mic’d with the can’t-fail combination of a close SM57 and a ribbon mic a few feet off; in this case, a Shinybox 46MXL, IMO one of the best values in a current-production microphone. 

Gold Coast Recorders has a circa 1960 Hammond L-101 (at right), which sonically splits the difference between a classic Hammond tonewheel sound and a voltage-divider organ (e.g., a Farfisa).  What it lacks in sonic heft it more-than-makes up for with the amazing psychedelic effects-option board you see installed at the lower right.  On the Left is GCR’s new Hammond A100, which is the same thing as a B3 except that it has built-in speakers and a reverb section.  We’re using it with a Leslie 51.

Percussion via several Sennhesier 441s and an AKG 414 overhead.  Room is mic’d with an XY pair of Neuman TLM 103s, a great choice for room mics owing to their incredibly low self-noise and very high output.

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Uncategorized

‘We Shape Our Tools, And Thereafter Our Tools Shape Us’: MM

(Image Source)

As I wrote on day 1, the goal of this website is to investigate “the potential (of sound-altering audio technologies) to create meaning for the people who experience these new sounds.”  This can be as broad as audio-tape domesticating and institutionalizing  surveillance, or a limited as attempting to decode the visual language of different electric guitar models (via my endless uploads of obscure vintage guitar paper items) and attempting to understand how, if at all, that certain vintage microphone preamp design really does make a tangible difference in the effect of a recording. Through it all, though, what’s crucial to me is the idea that /we make tools to serve certain ends/ …and then (also)… /our tools create and dictate our behavior/.   It’s this dynamic that I find fascinating about any technology, any medium…  since I work in sound + music, I investigate it on this particular plane.

I was recently reminded where this idea comes from; or at least how it first came to me; I was reminded that it stems from the writings of Marshall McLuhan, via books of his I picked up at various library-book-sales while in high school.  McLuhan was an academic and a media critic, but in the highly progressive and experimental time that was the late 1960s, he was able to cross over into the popular sphere, and the many millions of copies of his books in circulation guaranteed that any curious kid would find them eventually.   Not long after I first discovered McLuhan, I was off to college where I would study semiotics and cultural theory (along with music); McLuhan was rarely mentioned in my courses.  I can’t recall why this was, but he was not part of the program.  Nonetheless, the basic premise of McLuhan’s theories:  ‘We shape our tools, and thereafter our tools shape us’: this is parallel to the most basic principle of semiotics; the idea that /language does not describe that which is in the world/, but rather /we can only understand and ‘see’  the world through the filter of language/.  To put it another way: language is essentially limiting.  And: our tools do not ‘let us do whatever we want to do,’ but instead limit and in some cases dictate what we do.

Our friends J+C visited recently; C manages a bookstore and is therefore very up-to-date on the latest publications.  C mentioned that Douglas Coupland recently wrote a book on Marshall McLuhan; I am a big fan of both of these writers so this is great news to me.  NEways…  a few days later, McLuhan and Coupland popped up again in this NYT article.  McLuhan is apparently experiencing a resurrection in academic circles.  At the university where I teach, E and I are the only faculty to teach semiotics, so I don’t know how true this as; but much like everything comes-around in music, I imagine certain thinkers can regain a footing in academia.

I realize that this post has absolutely nothing to do with audio in particular, but MM has everything to do with why I think it’s interesting and important to look closer at the audio tools and technology that we use, and to (at least) try to understand how these tools and technologies interact with our work and our creative goals.  You can find a copy of his Understanding Media virtually anywhere.

Categories
Guitar Equipment Uncategorized

Carvin Co. electric guitars of 1978

Continuing our series on Carvin Musical Instruments of the 1970s:  the complete Carvin electric guitar line-up of 1978.  Download a twelve-page scan of the 1978 catalog:

DOWNLOAD: Carvin_guitars_1978

Products on offer include:  Carvin DC150C, DC150B, CM140, CM130, and CM120 electric guitars; the Carvin CB100 stereo bass, and the DT630 and DB630 doubleneck instruments.

By 1978, Carvin had abandoned the slightly Fender-influenced European-made guitar components they had been using since the late 60s; the 1978 lineup is much more Gibson influenced; or maybe Gibson-by-way-of-Alembic.   Noteable late-70s trends at work here include: solid brass hardware; heavier (8.5 lbs) instruments; humbucking pickups with coil taps; ‘natural’ finishes; and plentiful control knobs/switches ala Alembic and BC Rich.

One odd holdout from the earlier era of the electric-guitar is the fact that these instruments shipped with a guitar-cable included.  I wonder when this practice finally ended.  Seems like a cable more ought to come with an amplifier than with a guitar… Also notable that the bass-instruments shipped with flatwound strings standard.  I have noticed that there is a definite trend lately for electric-guitar players to use flatwound strings again; I have been really enjoying the sound of flatwounds on my 60s Fender and Harmony guitars; it’s kinda the secret ingredient to get the sound of 60s records (assuming yr using an old gtr and an old amp as well).  The only problem is that they are more expensive.   $12 vs $5 for roundwounds.  On the other hand, they rarely break, and it’s not necessary to change them as often, as a ‘dulled’ sound is sorta the point.

Previous 1970s Carvin coverage on PS dot com begins here…

Categories
Microphones

The American R331 Ribbon Microphone of 1950

A corollary to the theory that “an infinite number of monkeys typing at an infinite number of typewriters will eventually produce the complete works of Shakespeare” is my belief that you can eventually find any LP record you’d want to buy for $1.  (OK maybe $2).  So far this has worked in my favor, although it does require a lot of discipline to keep it in practice.

It’s kinda similar with microphones.  Based on the large numbers that they were produced in, the wide range of industries that they are used in, and coupled with the relative durability of these objects and the relative degree of respect that people treat them with,  if you keep digging long enough you can find pretty much any old mic for a song.  This has proven true for me for everything up to and including vintage Neumanns.  I have not found a $100 C12 yet, but I will.   NEways…  found the above-depicted American R331 for a few bucks yesterday in the last minutes of a yard-sale.  I didn’t know anything about it, and I was not optimistic that it would work.  Turns out that with a slight adjustment it worked fine, and it actually sounds pretty good IMO.  You can make your own assessment based on the recording that I’ve posted at the end of this piece.

The R331 dates from 1950.  It is a ribbon mic.  It was the cheapest of 3 identical-looking ribbon mics that American produced.   I feel like it’s survival can be at largely attributed to the fact that it shipped in the compact, attractive box seen above.  The physical design of this mic in general is really spectacular; the whole thing is machined from solid metal and it is very classy + timeless.  American was a division of the Elgin Watch Company so perhaps this has something to do with the very strong design presence of these mics.

The text on the outside of the box promises ‘Full-Vision.’  I was excited when I saw this, as I imagined that this indicated ‘full frequency response’ or some other relevant sonic characteristic.  As it turns out, this marketing-speak concerns the small physical size of the microphone.  As one commentator writes, “ It is a compact microphone, only about 6 inches long and 2 inches in diameter.  On this basis, American called it a “full vision” microphone, an allusion to the face-blocking size of some of their competitors’ products, such as the RCA 77 and the Altec 639.” (Source).

Above you can see the mounting-base of the mic (attached to the body of the mic by a solid-rubber grommet; no need for a shock mount!) and the unusual mic-clip that the R331 requires.  My yard-sale mic did not come with the clip; only through some miracle did I have one of these clips in a box of parts that I had around.  Weird.

When I plugged the mic in, it worked fine, but the output level was very low, even for a Ribbon.  I wrote S. Sank to inquire if he services these microphones; Sank has done an great job fixing some other 50s ribbons that I have.  His reply: “(American Ribbons) are generally pretty high output…. so you should try one thing ….which is to remove the label plate and change the jumper to a different impedance setting.  The plate should have a paper label on the back of it to show what’s what.  The only weakness of these mics is that sometimes an impedance tap will go bad.”

I tried this, and it turns out the only issue was that one of the jumpers was not secured.  Tightened one screw and done.  Thanks again S!

As far as specs, original paper material, etc: the always-helpful microphone database of Stan Coutant has a very detailed page on these microphones, so no need to re-tread those waters.  Let’s get on to the sound…

LISTEN: American_R331_amazing_grace

For an unrestored 60-year old ribbon mic with a stated response of only 50-8000 hz, I think the sound is pretty remarkable.  It’s a little hiss-y, but that’s somewhat due to the shitty mic preamps in the mBox.  I am confident that this mic could yield a good result with a proper studio mic pre.    BTW, you are hearing a solo finger-picked guitar performance; no EQ; the only processing is the digidesign ‘Maxim” taking off about 2dbs on the peaks.

Anyone out there using the American ribbon mics in their work?

Anyone have any experience with their high-end DR330 variant?

 

Categories
Microphones

Radio Communications Mics of the 1940s part 2

The Electrovoice Cardax Crystal Cardiod Microphone

Today we’ll look at some more microphones on offer to Radio Hams in the pages of QST Magazine circa 1947.  The Electrovoice Cardax pictured above seems to have been a popular choice; this mic appears on photographs of numerous Ham radio shacks of the era.  It is odd then that I have never come across one of these in all my years of digging.  Are crystal mics less reliable than dynamics?

The Cardax again; also pictured is the 910, also a crystal, although presumably an omnidirectional.  Half the price.  Anyone using one of these?

And the Cardax yet again.  Here we learn that the Cardax has a presence-boost switch that adds a 7db peak at 4000 hz to add intelligibility to speech.   Sennheiser notably offers this feature (well, similar enough) in their 441 cardioid dynamic.  Good for use underneath a snare drum. (the 441, that is)


Astatic (seemingly) made microphones exclusively for the ‘communications’ (as opposed to recording or live-sound-reinforcement) market.  The Astatic D-104 is the most iconic of Ham radio mics.  The D-104 consists of a removable ‘head’ that attaches to a transistorized base with a push-to-talk bar.  Above are a few of the ‘heads’ that mate with the D-104 base.  Now that I think about it…  what were these heads used with in the 1940s, prior to the introduction of the transistor?

Above is my D104 base with the working heads that I have accumulated.  I’ve bought plenty of non-working ones as well.  The ‘bullet’ shaped heads are dynamic and the round ones are crystal element.

Here you can see the head removed from the base.  As i said earlier, the base consists of a 9V battery-powered preamp and a large ‘push-to-talk’ bar.  You will usually find these units with a 4 (or more) pin output connector designed to mate with some certain Ham radio transmitter.  I modified this one to have a standard XLR-M output jack. It seems to work fine into any mic preamp.  So…  what can you do if you want to use these heads without the noisy, bulky base?

At some point I came across the 3-pin-Amphenol barrel-adaptor in the center above.  Add a short length of wire and an XLR-M and voila.  Seems to work fine into the mic preamps in my little Mackie test-mixer.  Which I imagine has fairly high input impedance, likely 1500 ohms or more.  Honestly not sure if the performance would be the same into a 150ohm or 600 ohm mic input but…  point is, if you find some of these heads, yes they can be used easily without the base unit.

Alright back into it.  Above is the Astatic Synabar.  Never seen one of these.  Seems to be identical to the EV cardax: same feature set, pricing, etc.

********

Above: an advert for the Shure ‘Versatex,’ a plastic-bodied crystal mic.  Great design.  And very rare AFAICT.  To the right we have the venerable Shure “556” broadcast-dynamic mic, one of the better -quality microphones made in the 1940s.  The best modern comparison would probably be the SM-7.    Anyhow, the fire-damaged  556 is depicted here not to sell 556s, but as “a living testimonial to the ruggedness and dependability of all Shure Microphones.”  Presumably this does not include plastic microphones such as the Versatex, which could not fare well in a firey inferno.  The advert goes on add: “For Ham use, we recommend the 708A Stratoliner and the 707A Cyrstal Microhones.”

********

And there you have it.  The 707 may look like the famous Shure ‘Green Bullet,’ but the element, and the sound, is completely different.  The Green bullet uses a dynamic element with a property that Shure calls ‘Controlled Reluctance,’ which basically indicates a dynamic mic element that does not require an output transformer to mate with the input transformer of a mic preamp. The 707, on the other hand, is a crystal mic.

Categories
Microphones

Turner Ham Microphones of the 1940s

The Turner Model BD Microphone

Today we’ll look at several Turner microphones of the 1940s which were marketed to Radio Hams in the pages of QST.  The development and marketing of recording-studio microphones is generally oriented towards full frequency response, low self-noise, and the ability to handle large sound-pressure levels without distortion.  The development and marketing of live-sound, I.E., PA-system microphones places a definite emphasis on these points as well, but with an equally strong emphasis on durability and feedback rejection.  Ham, or ‘communications’ mics, on the other hand, have the unique distinction of being designed to emphasize the frequency range most necessary to intelligible human speech: approx 500hz to 5000hz.  This is done to ensure that the broadcast will only issue forth the necessary sonic information: the communication value of the words themselves.  Fidelity to the actual tone and timbre of the speaker, and/or the sonic representation of the speaker’s environment (IE the room he/she is in) are irrelevant for this activity.  So when you think about that ‘old mic’ sound, yeah, it is somewhat the result of primitive technology.  But it is also in-part an intentional, engineered condition.

The Turner Model 20X Microphone

The Turner Model 22 Microphone

The Turner Model 33 Microphone

The Turner Model VT73 Microphone.  This model of microphone was also manufactured with a built-in control knob to operate a wire recorder.  Not so different from the USB ‘podcasting’ mics of the 2010’s: combining the acoustic-pickup device with certain elements of the actual recording apparatus (I.E., the d/a convertor and mic preamp) into a single unit.

Categories
Publications

QST Magazine in the 1940s

QST magazine is the monthly publication of the American Radio Relay league (h.f. ARRL).  ARRL has published QST since 1915.   The ARRL is the main membership organization for ‘Hams,’ otherwise known as amateur radio operators.  We discussed Hams a bit in this previous post on vernacular graphics.  I am not a Ham radio-operator, and I know next to nothing about radio-frequency broadcasting equipment.  But, since most Ham radio broadcast-chains begin with the human voice and a microphone, and it is largely a DIY-type activity, there is plenty of relevant content in these old magazines.

Above is the ARRL’s mission-statement as published in 1947. Anyhow, over the next few days I will post a few interesting bits from QST in the immediate post-WW2 era.  There was a tremendous surge in amateur radio activity at the time, owing to the return home of the servicemen who had learned radio-technology in the war.

These men had been given an introduction to radio and electronics in the most intense possible situation -the life-and-death struggle of global warfare – and it’s no surprise that this powerful link would fuel an intense post-war peacetime interest in Ham activity.

Above: a Tom-Of-Finland-esque advert for Solar Capacitors from a 1947 QST.

We’ll start today with a couple of interesting schematics for push-pull audio amps: a 6F6 15 watt push-pull amp, and a cathode-coupled 6L6 40 watt amp.  I have never used a 6F6.  Anyone?  And I don’t recall ever having seen a cathode-coupled push-pull driver circuit.  Check ’em out…

Tomorrow: Turner Ham mics of the 1940s.

 

 

Categories
Guitar Equipment Publications

Out-Of-Print-Book Report: “Electric Rock,” Richard Robinson 1971

“Electric Rock” (Pyramid Communications, 1971, 224pp) was written by Richard Robinson.  It’s a small paperback volume, mainly text, which offers an assessment of hundreds of the guitars, basses, amplifiers, and PA equipment that were available to the American public in 1971.

There is also ample text devoted to basic explanations of subjects such as ‘What is a piggyback amp?’

And in case you were wondering:

Try saying “The Shape Most Often Used For Rock Is Darkened In” 10 times.  It will assume a mantra-like quality.  And then you will know the shape of rock (darkened in).  “Electric Rock” is filled with plenty of such slightly-off prose.  It’s written in a circa ’70- streetwise-hipster voice, and this is not at all surprising once you learn a little about the author.  Richard Robinson is a fascinating character.  His slightly mean-spirited AllMusic profile tells most of the story.   RR is most famous for co-founding ‘Rock Scene’ magazine and for producing Lou Reed’s unsuccessful first solo album.  But he also produced a few of my personal favorite records of the era.  Check these tracks out…

Teenage Head by the Flaming Groovies

Sifting Around In a Haze by Andy Zwerling: 06 Sifting Around In A Haze

Reachin’ by Hackamore Brick

Anyhow.  Point is, RR had his finger on the pulse of a lot of music which would never amount to much commercially, but which has very much stood the test of time artistically.  Kinda like…  Reed’s first band the Velvet Underground.  Pretty interesting… this guy definitely knew what he was doing.

In case you’re wondering what ever happened to Richard Robinson, well…  apparently, here he is in 2007.  Different line of work. Life is funny, huh?  RR, if you are still out there, drop us a line.

Oh BTW one more thing to add about “Electric Rock”:  Lenny Kaye wrote the forward.  The-Lenny-Kaye as in, created ‘Nuggets‘ (basically the holy canon of Garage Rock) and also plays guitar (since the ’70s) for Patti Smith.

Check out ‘Electric Rock.’  One copy currently available at Amazon dot com.

Categories
Concert Sound

Carvin Mixing Consoles 1979

Download a fifteen-page scan of the mixing consoles on offer in Carvin’s 1979 Catalog:

DOWNLOAD: Carvin_Mixers_1979

Above is the playing-field of the flagship Q1608, a Quadraphonic console with 16 inputs and 8 outputs.  Other mixers on offer: the Carvin S1800, S1200, MP1000, MC1000, SP600, S600, MP600, MC600, and MP410 mixers.

Above is the MP410, a lil dude with 125 watts (into 4 ohm), a graphic EQ, and a built-in Hammond reverb.  Seems like a pretty good little keyboard amp.

One of the most repetitive selling points in this catalog is the alleged superiority of the new differential  input stage relative to input transformers.  Both methods certainly have their benefits; nowadays, input transformers are almost universally used as a selling point rather than a liability.  I personally prefer transformers, and use the Jensen 115 (click here to download details) for most of my builds.

Tomorrow: Carvin guitars of 1979.  If you’ve been enjoying this series, check out the very comprehensive Carvin Museum.  The Carvin Museum does not offer full catalog downloads as I’ve been doing, but they have done an admirable job of scanning and indexing every Carvin catalog from 1955 through 2005.