TUBE-TYPE MIC MIXER, PART 2

     A reader complimented the schematic I posted yesterday.  Of course, that's the "clean copy."  Here's the one I drew as I traced it:

     You will note several layout errors that are corrected in the later version -- don't know why I omitted the headphone jack wiring in that one, though.  Schematic drawings can nearly always be improved after the first draft gets everything on paper (or on the screen, if you work that way).  The rules are simple, applying them sometimes isn't.

     And here's what I traced:

     The Thordarson "Tru-Fidelity" mic transformers are not original -- the fellow who gave me the mixer salvaged the original UTC transformers.  The Thordarsons are at least as good.  They're also larger.  I'm not happy with the length of unshielded wire in the grid leads, it will want changed.  Looks like I took most of the wire harness lacing out when I traced it, too, so that needs redone as well.  I wonder how those Sprague "Atoms" electrolytics are holding up?  (They're on the terminal board behind the right-hand mic jack.)
    
     Back panel:

     Blank and ready for call letters!  (It's traditional.)

     2" Cannon connectors, with a penny for scale and ancient masking tape stuck on the chassis:

     12-pin Jones plug, holes where a previous user had relocated the output terminals, fuseholder:

     Rannie the cat loves my fancy screwdriver set:

      This made disassembly a little more difficult.

     (Here's another take on a small mic mixer, kind of interesting...if you have the parts.)

TUBE-TYPE MIC MIXER

     It's been awhile since I traced the circuit and got it working:

     Naturally, it was not working when I took it down from the shelf.  Time to get out the signal tracer.

     At some point before I got it, the front panel was covered in wood-grain laminate.  I'm thinking a nice coat of plastic-friendly matte black would do it a world of good.  And perhaps some RCA-type knobs that had not been painted, too.

     (A word about the '2" Cannon' notation for the input connectors: that's what they are, great big old-fashioned microphone sockets.  A mic-connector roundup post is in the works to provide examples.)

THE FIRST PLAY-BY-PLAY MAN

     In fact, he probably invented the idea.  And he was a Hoosier.

    ...It was The Big Game -- and not a home game for his school's team.  The year was 1903.  University of Michigan student,  Indiana resident (and part-time telegrapher) Floyd J. "Jack" Mattice had already dreamed up (and sold to Western Union!) the notion of having sports-knowledgeable telegraphers transmit moment-by-moment scores and high points directly, instead of waiting on copy from print reporters and now he'd come up with another idea: a long-distance telephone line.  He'd describe the game to the other students back at UM as it happened.

     Bell Telephone installed a phone booth on 40-foot poles along the sidelines at mid-field and a direct line back to the auditorium UM. Shortly before the game began, Mattice climbed up and placed the call--

     But remember, this is 1903.  Electrical amplification is still several years away.  Backstage, ten more sports-fan students were listening in, each one in turn memorizing a few minutes' play and rushing onstage to relay it to the audience, and then back to his listening post as the next "sportscaster" took over, on after another.

     It was a popular notion.  At UM, the practice continued until radio broadcasting took over in the 1920s.  As for Mattice, he had another career; you see, he'd arrived at college already a member of the bar.  After graduation, he went home to Rochester practiced law, serving a couple terms as county prosecutor.  Even that wasn't enough -- during WW I, he went to work for the Bureau of Investigation's* office in Indianapolis and then at the U. S. District Attorney's office.  He went back into private practice a few years later and then served in various posts with the city, then back to Federal work during WW II, ending up as a prosecutor at the war crimes trials in Japan.

     Still, inventing sportscasting probably made more people happy than any of his legal work.  He retired to Rochester and passed away in 1971.  He maintained a lifelong interest in telegraphy and if you've ever wondered about the curious number of attorney/sportscasters (Howard Cosell, for instance), while I don't think Mr. Mattice can be blamed for it, he was certainly one of the first examples.

     (Crossposted from my personal/political blog.)

IT'S A KLUGE

     Once, there was a real Kluge:

     Myron E. Kluge, in fact.  In the years after WW II, he promised big things in the ham radio field, produced some fascinating ads featuring the very first "desk kilowatt" (a metal desk with a 1000W amplifier in it, a concept E. F. Johnson later built and sold in fair numbers) and faded from sight.

     Kluge Electronics had some interest in television (the 1946 "Radio" Handbook has an ad featuring the TV racks at Kluge Labs, looking neither more nor less of a kluge than anyone else's) and early FM but it either found a very obscure niche to vanish into or failed entirely.

DAYTON HAMVENTION 2013

     "Turk" Turon and I were at the Dayton Hamvention the better part of Friday and we saw about half.  It was amazing.  I passed up an early Globe transmitter -- next step smaller than the Globe King.  Shoulda, woulda--  Could not lift it.  Priced to move at $300 and in working condition.  Oh, if only!

    (I did manage a smaller/newer rig, a Heathkit DX-60, also said to be working.  We'll see.)

     Some rigs were way too big to move:

     Love that paint-job!
     This is the RF side; audio is the same size, with two more final-stage tubes and a nice window to enjoy them through.  Be sure to tune for minimum meltage.

     It's a Gates 1kW job, and very large for its size; but that just makes it easier to work on.  There was a Collins 20V in front of it, of which I hope to post pictures later.  Notice the bead-chain drive crossing the window?  The output tuning network is on the right side of the cabinet -- but Gates did't want all the knobs over there, that wouldn't be balanced!  So they extended it.  That means you'll be retuning a bit after start-up until cabinet temperature stabilizes: all that extra mechanical folderol carries a price.  The 20V has much the same trick, only with brass bead-chain, aluminum drive wheels and a steel cabinet, all mounted high up in a physically-smaller transmitter at the same power level, or, "Please touch up Loading adjustment once an hour until noon," as the note at one station read; they only ran the 20V one day a week and it woke slowly.

     Some hair was movingly big.

     Kristen had admirers wherever she went.

     Table of Vibroplexes.

     The new owner is just out of the shot.  Have I mentioned how good Vibroplex parts support is these days?  It is and you can think him for it.

     Turk found a man-sized soldering copper.

     Well, more like statue-sized.  When they build the Radio Row monument in NYC, it'll be holding one of those, looking out at Lady Liberty as if wondering about asking to borrow the torch.

STANCOR 10P PROGRESS REPORT 9

     Wiring.  A lot of thinking, rethinking and ground points needing to be added.  Also, I really need to stock up on cloth-covered wire, the good stuff.

     Crystal oscillator, wired.  RF power amplifier, mostly wired -- tank circuit being the main thing to complete.  Modulator, partially wired.  Power supply, still to do.

     It's just about to the "install front panel and controls" point.

HISTORICAL RESEARCH: NEWSPAPER ARCHIVES

     Looking for more information about the earliest days of television and FM in Indianapolis, it occurred to me that newspaper archives would be a great source; after all, the city has had some great newspapers: the Indianapolis Times (d., 1965), the Indianapolis News (b., 1869 - d., 1999, after a long illness; survived for a short while by Herman Hoglebogle) and the Indianapolis Star; two of those papers even owned radio stations, so there must be plenty of news about local radio to be found.

     Possibly there is, but not online from those sources; the "morgue" files of the Times and the News appear nowhere and the Star has a gap from 31 December 1922 to 21 May 1991.

     One newspaper has extensive archives, wonderfully searchable, compiled by IUPUI: the Indianapolis Recorder, which has served the city's African-American community since its inception in 1895.  And on 13 July 1946, WABW shows up, in an ad for a song to be broadcast on the 17th of that month at 5:30 p.m..  This was a standalone FM, in a time when few FM radios were available, so it's especially interesting to note the ad doesn't list the frequency.

     After the ownership and call letter change, WXLW and (simulcast) WXLW-FM schedules and coverage show up frequently in The Recorder: WXLW had no network affiliation and a policy of not running drama or "chat" shows.  They block-programmed many kinds of music, including programs aimed at the the paper's readership. (But, as a 1948 article puts it, not "hot jazz or drum solo type of so-called music."  It was another time and the front-page headlines make for sobering reading.)  Published schedules make clear that the FM kept running until late at night, long after the AM shutdown at sunset.

     At least there's one newspaper in Indianapolis with a sense of history.  Thank you, Recorder.