Magnecord History: The Book: circa 1950

MagnecordIncCoverMagnecord, along with Ampex, was one of the first manufacturers of professional 15ips hi-fidelity tape machines in the world.  While not remembered as clearly as their rival, Magnecord built a tremendous number of machines, and many of them have survived to this day.  We have two at Gold Coast Recorders and after minimal repairs they still work just fine, nearly seventy years after their Chicago manufacture.

Magnecord_Advert_1950I picked up our two Magnecord PT6s at the Elephants Trunk flea market a few years ago for $25 each, and shortly after posting some new recordings made that I with the PT6s I was contacted by D. Boyers, son of Magnecord co-founder John Boyers.  D provided us with an incredible amount of impossible-to-find archival material from Magnecord; you can start to dig through it at this link.

Magncord_foundersFast forward to 2015: D. recently located a long-lost 45pp book that Magnecord created in 1950, presumably for the purpose of pitching new business to the US Government.  In his words:

“I have uncovered what appears to be a very complete book detailing several aspects of the very early years. This 45-page document provides an inside look at the roles of key personnel within the organization, including several photos of workers and assembly facilities in the early factory.

The book appears to have been put together in about 1950, four years after Magnecord was first organized, and it lists several of the early accomplishments of the fledgling company, including their first year of a million dollars in gross sales. (Back when that was serious money)”

You can download the entire 45pp volume (posted as five PDFs due to file size) at the links immediately below:  DOWNLOAD:

Magnecord_1950_part_1

Magnecord_1950_part_2

Magnecord_1950_part_3

Magnecord_1950_part_4

Magnecord_1950_part_5

EngineeringDepartment_MagnecordThis book offers an incredible look into the very first days of professional magnetic recording as well as capturing the enterprising spirit of a young pro-audio company growing fast and seeing limitless possibilities ahead.  Enjoy -

MetalWork_magnecord Magnecord_Installation Magnecord_Army  FinalTestingStation_Magnecord DraftingRoom_MagnecordRecordHeads_Equalizers_magnecord

LINK TO LISTEN: “I Swore I’d Never Go Back” : Live Radio Show March 22 2015: The Nineties

IMG_2516We put together an EMERGENCY SHOW for an overnight  on WPKN 89.5 FM.

My special guest is noted 90’s fanzine creator Emily Muffinbones and we will be bringing you THREE HOURS of nineties indie, lo-fi, and ‘complaint rock’ as my pops used to call it.  All from the original 33RPM LPs and 45s.

this program has now aired, but you can listen at this link,,click here,,,

Click the link below for the complete setlist.

Continue reading LINK TO LISTEN: “I Swore I’d Never Go Back” : Live Radio Show March 22 2015: The Nineties

INDIAN POINT doc feature w/our analog synth score to debut at Tribeca

IndianPointFilmIn case you’ve been wondering, “but what does he DO with that sound equipment,” earlier this year I had the chance to work along with composer Nathan Halpern on director Ivy Meeropol’s documentary feature “Indian Point.” We are pleased to announce that the film will make its world premiere in competition at the Tribeca Film Festival.  Our extensive score features a wealth of vintage analog and digital synths and the film is a must-see for anyone interested in our energy future.

The Fairchild Model 605 Stereo Tube Phono Preamp c. 1959

Fairchild_605_606_preHow y’all  doing on this frigid day in March,,,  so listen, srry abt not posting much new material this past year.  I’ll be frank: as phones keep getting better and better, and online content keeps getting more and more tailored TO the phone as a consequence thereof, many of us are spending less and less recreational time in front of the laptop (although I am still planted in front of some sort of Mac, invariably, for my production and composing work,,,) and more of that ‘leisure’ time with the phone.  Instagram rather than ‘scoping blogs’ seems better tailored to how most folks are spending their recreational internet time these days.  So we’ve been keeping an active+vigorous presence up there.  This blog isn’t going away, but do check out the IG account if you have not yet.

Fairchild_605_606_PS_outputOk NEways,,, I was diggin thru the archive for something today and I came across the schematic for a phono preamp that Fairchild offered around 1959 – their model 605.  Strangely enough, their prototype (image at head) was labeled ‘606.’  Production examples do bear the mark 605, though, as this example from a Russian website indicates:

Fairchild_605_606(image source)

There is very little information on the web about this unit – in fact, a google search offers,,, good ‘ole Preservation Sound Dot Com as its first result when queried.  And not much else of relevance.  We apparently ran an advert for this very unit some years back (click here for that earlier post).  So I was very excited to see that this unit, which is VERY buildable using off-the-shelf components, had not yet ‘migrated’ onto the web.  The Fairchild 606 offers both MC and MM input stages, 600ohm balanced outputs, and selectable EQ curves and stereo or true mono LP operation.  Now, I’ve built many Marantz and RCA-style tube phono preamps to great success, but this Fairchild is simultaneously exotic AND obtainable enough to be quite intriguing.   So, DIYers of the world, here ya go:  knock yrself out:

Fairchild_605_phonoPre_Schematic(click on image for a (huge) full size image)

There’s nothing exotic in it: no custom inductors, weird-taper pots, or un-source-able transformers.  The toughest thing to find might be the 4P/6T switch, but you could always sub in a pair of 2P/6T switches and just use two hands.  In fact, the input transformers, which I can confirm are 1:20 from the 600 ohm tap, appear to be garden-variety Beyers:

Fairchild_605_inputTrans(image source)

Regardless, though, you can use any hi-fidelity input transformer with a roughly 1:20 ratio and an input impedance approx.  10X whatever the output impedance of your moving-coil cartridge is.  And if you only use a moving-magnet cartridge, you can skip that part of the circuit entirely and just build the 47K ohm grid-input stage (and all that follows).  As the schematic indicates and the images confirm, this product was built in two chassis:  (preamps+EQs) and (power supply+output stages).  Other details: R109 and R209 are level controls, basic voltage dividers with a 20db range.  EQ offered is flat, RIAA, or RIAA plus add’l roll-off, and the ‘Lateral’ switching positions offered cancel out the vertical tracking information, resulting in the cleanest possible sound from mono records.  The output stage is fairly conventional, but interestingly enough requires single-ended transformers, so you will be rather limited in your options here (a 15K:600 that can handle 8ma DC unbalanced, such as a UTC A25, should work fine).

This is a fairly advanced project, which I have personally not built (yet). I cannot offer any technical support or help with this.  If you have never built a vacuum-tube phono preamp or mic preamp from scratch before, I would not advise undertaking this project.  Good luck, and if you build one, send us some pics!

Streaming Now: Wed 2.18.15 Live Radio Show: ENO + CALE

Eno_Cale_1990Update: this program has now aired, but you can stream it at this link.  Enjoy!  c .

This Wednesday the 18th we’ll be doing a special live radio broadcast on WPKN 89.5 FM in the New York Metro area from 8PM- 11PM.  I’ll be on-air with my good friend JBW.  We’ve put together a three-hour retrospective of the careers of Brian Eno and John Cale.

calenoblogThese two legendary performers and producers have shaped so much of the better part of pop and rock music for the past half-century (fkkn nuts, right?) and we will share with you a (by no means exhaustive) survey of their work in parallel.

nico-cale-enoThere are so many interesting connections between these two, and common to it all is the basic premise of injecting an avant-garde sensibility into mainstream music and life.  As per usual on Preservation Sound Radio, we will be broadcasting from the original vinyl LPs, with very few limited exceptions.  Tune in on yr radio dial or stream the show live from anywhere on the planet at WPKN.ORG.

(above: with Nico)

The 1959 Ikegami-Tushin Limiter Inspired by the RCA BA6A

NHK_D_1Reader S. Komiya recently contacted us with some information regarding the Ikegami-Tushin limiting amplifier, an RCA BA-6A inspired piece that was built for Japanese broadcaster NHK in 1959.

SK has been so kind as to provide the schematic for this obscure device, as well as some background information.  I am posting the schematic full-size, so you can control-click it and download it for detailed viewing.

00_schematics_ikegami-limiter1959NHK_E1The photos in this post come from this Japanese auction website; the device pictured here recently sold for just Y30,000 ($300 USD).  And in working condition. 

600x450-2015011900002Here’s what SK has to say about the Ikegami-Tushin Limiter:

‘(It is) very much inspired by the RCA BA6A for sure.  It even looks a bit like it.  The tube format is very similar:  just change 6sk7 to 6ba6, 6j7 to 6au6 those goes into 6v6 PP and transformers between 6au6.  6ba6 were popular and cheap in japan because we made those a lot in japan in the 1950s and 60s.

6sk7 and 6j7 were never made in japan.  This unit also has an extra gain stage before first stage, which is pretty neat.  The components seem very high-end and some are custom made for this.  When i was gathering info about the ba6a in old tube shop, an older ham radio guy told me that he DIY’d one of these a long time ago…’NHKH_1NHKF_1*************

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20141230_123551SK also recently built his own BA6A from scratch.  It is depicted above, and you can hear audio samples of it at his soundcloud page.  SK has also scratch-built the Federal AM864 tube limiter, and he has this to say about the projects:

“The sound you will hear in soundcloud is a good comparison with the fed864.   The fed has good high open but compressed sound,  the ba6a has low mid, ton of low mid. I love them both.  The first time I used them was at a studio in Chicago back in 90s when I was living in US.  At that time I was using LA-2A mainly, but that studio had a Fed864 and BA6A.  They blew my mind, and since then I wanted them so bad!’

SK also provided some build-notes on his BA6A project; if you are planning on building you own BA6A, you might find these useful:  S_Komiya_RCA_Ba6a_DIY_notes

An DIY Tube Mixer Project c.1954

TubeMixer_DIY_1954Today’s article scan, again via reader Bill W., was written by one John S. Carroll and originally appeared in RADIO & TELEVISION news in 1954.  It describes a four-into-one mixer based on a design spec’d by UTC.

DOWNLOAD THE COMPLETE ARTICLE: 1954 Audio Mixer

1954_tube_mixer_rear1954_tube_mixer_bttmThere’s nothing terribly interesting about this particular circuit other than the output stage, which is push-pull and and is driven by a 3:1 interstage transformer which functions as both a phase inverter and provides a bit of additional voltage gain.

Output_stageI’ve never made a mic pre with a transformer phase inverter, but it could be very cool.  At Gold Coast Recorders one of the engineers’ favorite mic pre’s is a custom unit that I built based around an RCA 9362 cinema line amp (see earlier article here).  The 9362 is a push-pull output module, and it’s definitely a different sound – almost every tube mic pre made is single-ended.  Anyhow, at some point I will def build the circuit above into a mic pre.  Probably as soon as I find a pair of appropriate hi-fidelity (and shielded!) transformers for a buck.

1954_mixer_schematic

information and ideas about audio history