DOWNLOAD: Martha Hyer 1957 Radio TV News

Hyer is shown above in the midst of assembling her PERI 50, a mono hi-fi amp of the late 50s.  You can download the schematic for the PERI 50 here: DOWNLOAD PERI 50 SCHEM.  It’s a 50-watt ultralinear amp of extremely simple, efficient design.

Thanks to PS dot com reader T.F. for providing this article.  This piece comes as contrast to typical Women-In-Fifties-HiFi depiction, examples of which are in this series of images.    Despite the fact that ‘soldering-your-own-amplifier’ falls much closer to the wine-rack rather than gun-rack end of the macho spectrum, there was apparently nothing in American culture of the 50’s that could not be bro-ified, as this charming shop-apron of the era makes apparent:

Despite its intended message of unapologetic philandering and stamina, I kinda of get the impression that dude’s workmanship is shoddy and he has a shrill voice.  Maybe not the best image to project.  Thank god for social progress.  And on that note: does this website have any female readers who build/service audio equipment?  Drop us a line and represent…

Above, an interesting boost-EQ stage that could be helpful in an instrument or mic amplifier.  Can any of our helpful readers advise which caps or resistors in this circuit could be modified (and within what range) to alter the turnover frequency of the two filters at work here?  I am guessing that the answer is: all four caps that follow the input DC blocking cap… which would basically get us back to this piece, which i swore i would never build again…

Above, the most complicated tube amp I have ever seen.  Kinda feel like Shadow Hills Engineering must have come across this image at some point.  Dynamic noise suppressor, phono pre, two eq controls, visual feedback of high and low frequency drive, variable metering, tons of input switching… talk about the kitchen sink.  This project is organized around the very interesting 6AS7G dual-triode power amplifier tube: basically two 2A3s in one glass envelope with a 6V heater supply.  This is potentially some useful information, especially when you consider that a 6As7G is only about $13 from AES (priced out 2A3s lately?). I think that there could be a unique new guitar amplifier in the works soon…

My lord.  At least they didn’t try to thrown in an AM/FM tuner.  Follow the link at the end of the this post for schematics and parts lists for some 6AS7G amplifiers.

‘Audio Anthology Vol 1’ is available at Amazon dot com.

FOLLOW THE LINK BELOW for 6AS7G project schematics…

Above, the basic 10-watt 6AS7G amplifier schematic.  I imagine that an additional input stage might be required for use as an instrument amplifier, probably just a single 6J5 ahead of the volume pot… and you wouldn’t want that pot loading your guitar pickup anyhow.

…and above, the schematic for the monster illustrated earlier.

Anyone out there ever scratch-built an all-tube amp of this (or greater…) complexity?  Send us some images…

The Williamson amplifier is considered one of the earliest hi-fidelity audio amplifier designs.  It is certainly one of the most popular audio circuits ever developed for DIY’rs.  Without fail I seem to turn up at least one home-brewed Williamson every year at the local estates+fleas.  A PS Dot Com reader from the UK sent us the original articles from “Wireless World” as published in 1947.   I have yet to build a pair of these myself, and the idea of starting ‘from the top,’ as it were, with the original design, is appealing.  A few things to note: check out the provision to balance the driver stage, and separate bias level and balance controls for the output stage.  Also: check out R25: the formula for determining the feedback loop resistor.  I wish every schematic included this notation.   NB: the ‘L63’ valve is simply a 6J5 – aka, one half of a 6SN7.  the ‘U52’ rectifier is a 5U4 or equivalent.  ‘KT66’ is a better-performing 6L6; feel free to use 6L6 or 5881 if necessary.

  I picked up a big pile of old audio equipment this past weekend; notable items included a Shure Level Loc, a massive Bogen tube pa head, a kit-built Acrosound ultralinear 5881 amp, and a Gibson acoustic gtr case from the early ’60s (no gtr).  Also included was the mono amplifier shown above.  It’s a push-pull amp, cathode biased 807s, with 6SN7 driver and phase inverter; there is also a 2x 12A_7 preamp section with this ‘remote’ control section attached via 10′ of cabling…

After a little cleaning, the amp actually works fine if I remove the ‘remote’ and input directly into the final 12AX7 stage prior to the phase inverter.  As far as actually using the remote, well, I can’t quite figure out what sort of patching needs to be inserted with the two RCA jacks and one RCA male plug coming out of the face of this thing.  It’s a little bewildering.  If anyone can tell me who made this amplifier, I imagine I could find the schematics somewhere.  There are no markings on the unit anywhere besides an inked serial number inside the chassis and the letters ‘MP’ on the remote.  I am sure that this is a factory-wired unit, as there is tamper-paint on every solder joint.  BTW, I added the on-off-switch and the IEC socket on the side, so don’t let those two details derail your ID’ing efforts.  I am guessing that this a circa 1955 unit as the 12AX7 was only introduced in 1953, and the 807 craze was in the process of winding down by ’55…  so we’re likely looking at a unit made between 1953 and 1958.  Any ideas, please let me know.  This thing is 95% of the way to full operation and I’d like to get it running strong again.  It’s a tremendous looking piece, and it has a lot of volume.

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Updated: the mystery has been solved.  This amplifier was built by the Saulnier Music Service of Columbus, Ohio; so sez the son of the man responsible.   Read the comments section for the full story.  I am still in a need of a schematic (or even just a manual?) for this thing so that I can figure out what do do with the assorted preamp jacks n’plugs.  According to our poster, this circuit came from a transformer manual; which would likely mean a Stancor audio-manual circa 1954.  Anyone?

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.’

DOWNLOAD: Mullard_520_amp

American industrial titan RCA offered schematics for a variety of tube-audio equipment in the back pages of their many “receiving tube manuals.”  Mullard, a prominent British maker of vacuum tubes, similarly published a book entitled “Mullard Tube Circuits For Audio Amplifiers”  (h.f. “MTCAA”). The designs are quite different from RCA’s, as Mullard promoted different tubes:  EL34 rather than 6L6/5881; EL84 rather than 6V6; GZ34 rather than 5U4; and EF86 rather than 5879.   The MTCAA also offered extensive plans for the fashioning of the actual sheet metal cabinet and transformer-cover.  The four-page article I am offering here is quite different from the one in MTCAA, but either will get you on yr way to building this unit.

This design promises 35 watts from a pair of cathode-biased EL34s.  It does require an ultralinear (IE, with screen taps) output transformer with a 16ohm winding for the negative feedback loop (such as this EDCOR model), but other than that it’s all very basic parts.  Now if I could find some good cheap EF86s…  Anyone try the new $17 Electro-harmonix EF86?

BTW, The Mullard book is still readily available as a reprint; well worth the $17 cover price IMO.  There is a circuit for a 3-stage ‘mixing preamp’ featuring EF86 pentode inputs with a 12Ax7 on the back end, the second triode of the 12ax7 wired as low-impedance cathode follower…  pretty tempted to try that one…  anyhow, you can buy ‘MTCAA’ at Amazon Dot Com or at Antique Electronics.

Heathkit!  I have one of these A7s and damn it is a good-sounding little amp.  Anyone have a spare they wanna sell me (for stereo…. naturally…)?

I tend to think of Newcomb as more of an industrial-sound/PA sound company, but it looks like they made some home units too.  I have one of those huge glass-covered KX25 PA heads as shown here; it’s always been a little flakey but I can’t bring myself to part with it cos it came from a Catholic church and the knobs are labeled “Pulpit,” “Choir,” and “Sacrament Table.”  Take that, Kick/Ld Vox/ Bckng Vox.

Dude went to prison in 1974 for lying about the value of a music-collection that he donated to a university.  Tried to get Mancini and Bernstein to back him up and they would not.  Life is long….

Electro-voice home hi-fi drivers c. 1957

Eico home hi-fi amps and pre-amps circa 1957.  Eico was essentially the ‘other’ Heath(kit).  Eicos could be purchased either wired or as kits.  Here’s a two-page article on their flagship HF60, a beautiful amp with EL34 output tubes and an ultralinear Acrosound output transformer.

On rare occasion, we are shown women in more active (IE., less decor) roles.  Here are a couple of examples:  the (potential) technician and the shopper.

Pilotuners were made for a very long time, in many configurations; I’ve personally bought two in the past year alone.  Complete 1950s hi-fi systems like C.M.s are rare these days for many reasons, not the least of which is the fact that many have been cut up and gutted for parts over the years.  It can be hard to find the space to incorporate a unit like this in a modern domestic-space, but for anyone who enjoys listening to 1940s and 1950s recordings, I can’t imagine a better way to hear it than on a system like this.

C.M. relates:

‘ALL PILOT electronics; Pilotuner tuner/pre amp, Miracord Auto Turntable.  Williamson Amp with a pair of Genelex KT66 tubes … Great sound: like you are really there. The Pilot pre amp tuner has adjustable AFC for the FM, EQ for the phono; roll-off  and turnover frequencies and a setting for early 78s; if you have 78’s, you need this eq setting to hear them properly. The built-in speaker cabinet is ported and bass reproduction is clear and solid. The High end on the triaxial speaker is great also. Speaker is branded University Sound; (this was) a division of Altec. Huge speaker with L-pads for the mid and high frequency drivers.

    ‘ This console, with the original Goodmans Speaker, won 1st place in a hi-fi show in NY city. My friend’s Father assembled it .This turntable has a Magnetic cartridge . A lot of systems then were (considered) hi-end if they had a Magnetic phono input . It has both LP and 78 needles switch-able without removal.’

‘This set sat inoperative for a long time . (I performed) a complete cabinet restoration, replaced a fuse, and cleaned the controls. This set really gets the job done. Pilot was really HI END; it was not as popular as Fisher or Marantz or Scott. People in the know knew about this stuff.’

See this link and this link for previous PILOT coverage on Preservation Sound.

(image source)

The Pilotrol seems like an attempt to satisfy the most compulsive hi-fi fans; it really seems like they tried to cram as many lights, buttons, features, and knobs in there as possible.  What with the excess of buttons, slant-front cabinet, and VU meter, Pilot seems to have been trying to turn the simple act of using your audio system into an experience; I see shades of ‘Mission Control,’ ‘The Cockpit,’ and maybe police radio as well in the design.  Anyhow, it’s too bad this is a mono unit; otherwise I’d be looking for one…

Here’s the schematic.  Nice pentode phono input.  Anyhow, we can see echos of the Pilotrol and its feature-laden ilk in much hi-fi gear of the 70s – consider a typical high-end receiver of that era.  Modern equivalents offer even more features, but nowadays the buttons and lights have been replaced with menus and screens.   In opposition to this thread, we have the minimalist streak best exemplified by Apple and its associates.   Which operating principle do you prefer?  Do you want the equipment to be in the background or the foreground of your audio-listening experience?  Exactly what is ‘the experience’ for you?  Hearing the sounds?  Or is the operation of the apparatus essential to your enjoyment? At what point will technology become so advanced and so pervasive that ‘controls’ themselves can only been seen as quaint and nostalgic?  Are we there yet?

See this link for some more thoughts on the function of ‘control’ in consumer audio equipment.