Author: chris

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Open Studio Event 2011

This coming weekend: November 12+13 2011: we will be having another Open Studio event at our arts building in historic Bridgeport CT.  Forty artists and fine craftmakers will open their studios and exhibit their work and their work-practices in our century-old lace factory, and this is only one part of a larger Bridgeport Arts Trail going on that weekend (read some media coverage of the event here).   Believe-it-or-not, our dusty lil post-industrial town features not one but three very large art-space buildings, and there is some fantastic work to see (and hear…).  After you’ve come by to listen to some of my Recycled Champs, the Model 22277 hi-fi amplifier, and my latest development in all-tube mic preamps (w/ ancient RCA 76 tubes), be sure to check out the work (and amazing studio) of the photographer Tom Mezzanotte, world-renowned quilter and textile artist Denyse Schmidt, and all the odd characters that have assembled in this strange+semi abandoned place that we call BPT.  If you’re lucky, you might even get to commission some print-on-demand work from my wonderful wife E., who will have numerous print-publications of her work for sale.  Details and directions below.

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Custom Fabrication Uncategorized

A couple of recent guitar amplifier builds *Revised (2)*

Cassius #10; aka #10 in the the ongoing series of Fender Champ-derived guitar amps built into recycled ‘found’ vintage speaker enclosures.  See here and here for some of the earlier examples. #10 is already sold, but will be avail for examination at the upcoming Open Studios event at our building this coming weekend.  Cassius #10 is my first ‘Cassius’ with an EL84 output tube: it’s basically the front end of a tweed fender champ married to the power stage of a Vox AC4.  Add a nice full-range 8″ Alnico HiFi driver and holy shit does this thing sound great.  Solid-state rectifier, no choke, extra filtering stage in the power supply.  Output transformer is from a 1950s R GE HiFi console; all other parts are new.

Of all the pieces that I have posted on this website this the past year, the one that gets the most page-views is still my scan of the 1970 ORANGE amplifiers catalog.  I’m much more of a large-combo-amp guy then a stack-guy so i’ve never owned an actual vintage Orange amp head.  That couldn’t stop me from building one though.

Above, my version of an Orange Graphic 80.  Two EL34 output tubes, two 12AX7 preamp tubes, effects loop, variable low-cut filter, adjustable ‘fixed’ bias.  Unlike an actual Orange Graphic 80, I used a high-voltage mains transformer and a 5U4 tube rectifier (Orange originally used a voltage doubler and a diode bridge).  I also used a slightly different supply for the grid bias voltage as my Hammond power transformer did not have a bias winding.  For the output and choke transformers I used pulls from a beat 1950s RCA PA head; it was rated at 30 watts (7027 tubes) so we’ll see how long this output transformer lasts….

The most unique feature of the Orange amps is the bit labeled ‘filter’ here; Orange called it the ‘F.A.C’ control; it’s simply a 6-position high-pass filter that follows the coupling cap before the phase inverter.  It’s composed of a 6-position rotary switch with 5 carefully-chosen caps strung in series between the taps.   Simple as it is, it does make for a much more versatile amplifier.  I recently built this circuit into one of my Cassius amps (already sold) it worked great there too.

Above, the preamp wiring. 

Want to know more about building your own Orange Graphic from scratch? Follow the link below to READ ON…

Continue reading “A couple of recent guitar amplifier builds *Revised (2)*”

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Altec Microphones

Studio test of obscure circa 1965 Altec dynamic microphones

L to R: Shure SM57; Altec 684 Omni; Altec 682 Cardiod; Altec 683 Cardiod

Altec made a great number of different microphone models in the 1950s and 1960s.  A certain few of these are still widely used in recording studios today: most notably the 639 ‘Birdcage’ dual-element microphone (see here and here) and their various small diaphragm ‘Laboratory’ condensers (see here, here, and here).

During this period Altec also made a variety of conventional-looking dynamic microphones, some of which have quite good specs on paper.  Today we’ll be having a listen to the Altec 682, 683, and 684.

I’ve prepared three stereo audio tracks which all document an identical solo guitar performance which we tracked in the big room at Gold Coast Recorders.   In each of the three tracks, you will hear a new-ish Shure SM57 in the left speaker, and the selected Altec mic in the right speaker.  I chose an SM57 as a reference because it is a microphone that most of us are very familiar with and it is often used to mic electric guitar amps.  I placed the mics a big further back than I would generally use a dynamic-mic on a guitar amp in order to minimize any differences that might result from the slight variation in mic placement in relation to the amplifier.  All signals were taken from the microphone into identical Sytek mic preamps and then directly into Aurora Lynx convertors and into Protools.  No processing whatsoever was used other than minimal Digidesign MAXIM on the bounce-buss to ensure strong playback level; it was taking off 0.3db at most.

Levels were matched initially by running a 1K tone into the guitar amplifier and then fine-tuned on playback to within the tightest possible margin.  The 684 Omni required 30% more gain to reach an equal level; the other three mics were within 5% or so of each other in terms of output.

Alright now that you’ve seen the setup, here is the audio:

SM57 vs Altec 682: SM57L_682R

SM57 vs Altec 683: SM57L_683R

SM57 vs Altec 684: SM57L_684R

Have a listen and draw your own conclusions.  My quick assessment: the 682 sounds pretty similar to the 57, but IMO a lot prettier, a lot more detailed, and just more presentable in general.  The 683 sounds thinner than the 57; bass is notably lacking and there is an aggressive character to the mids.   Not sure that I would ever select this mic for anything.  The 684 sounds like… an omni mic, so it’s not a valid comparison to a 57, but it does sound pretty decent as an omni.  Might make a good under-snare microphone.

All of these forgotten Altecs are available cheaply on eBay from time to time.  I’ve never come across one at a flea market or swap meet, though, so I don’t think they are very common.  From what I can tell from my limited sample-pool, the ‘A’ designation after the model-number indicates that the mic uses an XLR5 (rather than the current standard XLR3) connector.  If you get one of these ‘A’ designated mics, you will need to find an XLR 5 female jack.  Wire an adapter to XLR 3 as follows: (XLR5:XLR3) 1:1, 2:3, 4:2.   The ‘B’ designated mics seem to have our current-standard XLR3 jacks.  Again, I am not 100% about this distinction, so check closely before buying if you don’t wanna be soldering adapters.

Categories
Microphones

University Microphones circa 1963

Download the eleven-page University modular-microphones catalog circa 1963:

DOWNLOAD: University_Microphones_1963

Models covered, with text, specs, and photos, include University model 401, 402s, 501, 502s, 403L, 404L, Model 70, and Model 71 dynamic mics; and the associated Model SA10, PA10, SSP10, SP10, and CC10 microphone bases. By ‘Bases’ I refer to the lower-half of the microphone itself: the connector, stand-mount, and switch assembly.  Apparently the user could ‘mix-and match’ among the various University capsule/transformer mic bodies and whatever jack/mount/switch assembly the user preferred.  The catalog itself is formatted with a 1/3rd-page insert in order to facilitate comprehension of this ‘feature.’  Here’s an example:

I purchased a well-worn University handheld cardiod dynamic mic recently; it was a model 8100 I believe.  It was the first University microphone I can recall finding.   I picked it up with a nice older desktop stand and a big pile of useless old cabling for a few bucks.  It worked well, and once I constructed a proper cable for it was moved along.    University was a subsidiary of Ling electronics, as was Altec; that being said, there was no way to identify the 8100 as being possibly Altec in origin other than the fact that it used an uncommon XLR4 cable connector, as most 1960s Altec mics also do.  I don’t know if there is any significance to this.  The 8100 was sold to me with possibly the best microphone provenance I have heard in a long time; the junk dealer told me that it had been the announcer mic at the Wallingford Speedway, a (now defunct? Leveled?) Connecticut auto racetrack that I remember vaguely from my early childhood.

A similar model 8100 recently sold on eBay for the terrific  sum of $0.99; new in box, nonetheless; no stories of former racetrack glory accompanied that particular mic.  Dig the fantastic graphic design on the box.  Original eBay listing on-view here.

 

Categories
Antique Hi-Fi Archive

University Speakers Circa 1963

Download the complete 20pp 1963 University Speaker Systems catalog (in two parts due to file size)

DOWNLOAD PART 1: University_1963_p1

DOWNLOAD PART 2: University_1963_p2

Products covered, with text, specs, and photos, include: University Medallion XII speaker system; Classic Mark II and Classic Dual-12 speaker systems; Companion II, S-80, Companionette, and Mini-Flex, and Mini bookshelf speaker systems; the full range of two-and-three-way coaxial University components including 315, 312, 6201, 200, 308, 200, UC-153, UC-152, UC-123, UC-122, UC0121, and UC-82; and University woofers, midranges, , tweeters, and crossover networks including C-15HC, C-12HC, C-8HC, C-15W, C-8W, HF-206, UXT-5, 4401, C-8M, Sphericon, H-600, Cobreflex, T-30, T-50, N-1 High Pass Filter, N-3 acoustic baton, N-2A and N-2B crossovers, plus more.

Above, the flagship Medallion XII system in a variety of “select-a-style” grilles.  There is a pair of Medallion XII (in French Provincial trim, naturally) on eBay right now for $200.  University Sound was founded in 1936, and became part of the LTV_Ling_Altec family of brands sometime before 1963, and eventually became absorbed into the Telex corporation.

Above, the University Classic Dual-12 system.  These things look serious.  I currently own a University single-12 system; it is a corner unit from the Mono era; its has very nice cabinetwork and it sounds surprisingly good for a full-range 12″ system.

This catalog is obsessively dedicated to selling speakers to a male/female couple.   Nearly every human image consists of a sample couple in the throes of consideration.  Which system to buy for our home?  So much to learn.  Let University help you.  Honestly I can’t read the emotions in these faces.  Perhaps early-1960’s people had a different feeling-set than we experience in the (post-Vietnam/LSD/Civil Rights) era.  Confused by these photos, anyhow.  This series seems to suggest: 1) ‘quiz-show-don’t-know-the-answer’; 2) ‘I’m not really paying attention to you’; 3) (undeserved?) smugness; 4) ‘we’re on a boat, and you’ve been naughty.’

Categories
Publications Technical

Stancor Amplifiers and Full Transformer Data c.1937

The Stancor ‘306’ 6-watt PP audio amplifier

Download the 1937 (‘third edition’) of Stancor Transformers’ ‘Amplimanual,’ a 24pp publication which conveniently combines schematics for ten original audio amplifiers with full data for their entire line of transformers.  If you (like me) have some pre-war Stancors lying around and you are unsure what exactly what the specs are, this is a godsend (blogsend?  awful).

Split into two parts due to size:

DOWNLOAD SCHEMATICS:Stancor_Amplimanual_Schematics_1937

DOWNLOAD 1937 STANCOR  DATA: Stancor_1937_Transformer_Specs

Schematics are provided for Stancor’s own 303, 305, 306, 312, 318, 320, 325, 335, and 360 audio amplifiers.  The first ‘3’ in the designation seems to represent this ‘third’ edition of the publication, and the second two digits correspond with the stated audio-output of the particular device.   Looking through the schematics, you will see the following tube types most often:  6F5, 6C5, 6J7, 80, 6V6, 76, 6N7, 6L6, 6A6, and 6A3.

Above, the schematic and parts list for the ‘303,’ a microphone pre-amp.  I will be building one of these shortly.  I was most excited by this publication due to the 76 tubes in a few of the circuits.  I am close to completion on a novel microphone preamp design that uses a 76 tube as the input stage and I am in-general trying to get more into the early ‘two-digit-designation’ tubes: the 75, the 76, the 42, 80, etc…   we are looking back etc etc.

Above, an image of the Stancor factory which describes a certain transformer-manufacturing process which I will not put into text because I get enough porn spam as it is. 

Several completed Stancor amplifier units

Above, several transformer units photographed for the catalog with their model-numbers included via practical photography.  What a great design move this is.  I bet we see a return to this product-photography technique in the coming years.  ‘If you can find a way to do-it practically (rather than digitally), then do it practically!’

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Uncategorized

Microphones? Why would you ever use a microphone?

More seventies nonsense

Shit, man, just record all that shit direct!  You don’t need to mic it!   Naturally, a surface-transducer manufacturer would make such a suggestion.  But could you imagine?  Awful.  The sound of a great player with a great instrument can be wonderful.  But put that combination in a great sounding space and (well recorded) you can elevate it immensely. Or just run it direct.  Either way.

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Connecticut Audio History Guitar Equipment

Most Tragic Bands of All Time, part 1.

Badfinger endorse the Connecticut-made Ovation acoustic/electric guitar

What is it about Ovation guitars that repulses me so?  They don’t sound awful.  They were made in Connecticut.  They are very very circa ’71.  I once even saw a video of Thom Yorke in the studio cutting “Exit Music…,” a not-awful song from a not-awful album,  with a black Ovation something-or-other.  And yet.  Faced with the prospect of a playable $40 70’s Ovation at the flea market last week, I passed.  God only knows where that $40 went.  Just kinda feel like those things are cursed.

Also cursed: Badfinger!  So you’re a band.  Shit, you’re a great band.  The Beatles sign you to their new record label.  Paul writes one of his best-songs-ever for you, and produces the MFkkr.  You even go so far as to to pen ‘I can’t live if livin’ is “Without You,”‘ which becomes the defining song of one of the definitive vocalists of the (soon-to-be-over?) era of commercially-sold-recorded-musical-performances.   By the end of the decade, two of you have killed themselves and somehow you lost (like, literally, shit, i can’t find it) one million dollars.  You are Badfinger.

One of the best rock bands ever.

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Uncategorized

PA systems of the Seventies

Gibson GPA-100 PA system circa ’73

Seems like ‘100 watts’ was the likely answer to all yr PA system needs in the seventies.  I can’t imagine how folks were using SVTs and Twin Reverbs side-by-side with 100 watts for vocal reinforcement but i guess you use whatcha got!  Old guitars amps, keyboards, pedals, guitars…  they all seem to become ‘collectible’ or ‘vintage’ eventually.  Old PA systems… not so much.

Shure Vocal Master.  Goddamn they made a lot of these things.  Some are still in use.

Ovation IC One Hundred PA System

Randall RPA-6 PA system. 

The Yamaha Ensemble Mixing system.  Model is EM-90 I believe.  I bought one of these for $100 at a guitar shop in Hollywood about a decade ago.  It’s a powered mixer/PA head with a built-in analog beatbox and a great-sounding reverb tank.  The high-impedance instrument inputs also distort pretty nicely.  AKA the-KILLS-in-a-box.

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Uncategorized

Some 70s electronic oddities

The Computone Lyricon is an analog synthesizer with a wind controller interface.  The horn-controller responded to three input parameters: the keys (‘valves’) themselves, lip pressure, and wind force pressure.  It sounds beautiful.  Listening to this thing, I can’t help but think of the infamous Charles Napier ‘space hippies’ episode of Star Trek.

Other things that come to mind: Steve Douglas’ “Music of Cheops”;

(image source)

…and Quicksilver Messenger Service’ “Just For Love” LP. 

Kinda makes me want to get a CV wind controller for my MS20…

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“Maestro will travel anywhere for new sounds.” Indeed.  Maestro was the effects-device division of CMI in the 60s/70s. CMI was best known as the parent of Gibson Guitars in this era.  When I was growing up (late 80s/early 90s), Maestro effects were considered fairly shite by professional musicians and we could still readily find these things for a few bucks at yard sales and pawn shops.  M. has collected many of these units, so I’ve been able to use a lot of these things on recordings through the years.  Missing from this family photo is the epic ‘Universal Synthesizer,’ which is not a synth at all, but rather a very early (the first?) multi-effect unit for guitar ETC.  Synth or not, this device can make some fantastic synth-esque sounds with just about any input signal.

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The Ampli-Tek Phaser AT-10, circa 1973.  An early Leslie rotating-speaker emulator with a charming cottage-industry aspect.  This piece is truly lost to time.  Anyone?