Picture of front panel (70K jpeg)
Note: Some documents formerly listed here are now only listed in the "Tech's Filing Cabinet" and will removed from here.
Note: (Jan 2019) - Some tube data is being moved to the updated Archives section, and will be deleted from this page.
Various documents that reside on the One Electron web site:
"California 220,000-Volt - 1100-Mile - 1,500,000 Kw. Transmission Bus" an article from Transactions of the American Institute of Electrical Engineers (AIEE) by R.W. Sorensen, H.H. Cox & G.E. Armstrong, 1919. Discusses long-distance transmission line issues, as well as problem of integrating 50 cycle power systems in the Los Angeles area with the rest of the bus. 32 pages, 1.8Mb pdf format.
Radio Shack touting Ampex - An advertisement from the March, 1952 Electronics magazine. The model 400A had just been announced. Note the 307 instrument recorder (versions of the 300) and the 375 Capstan Motor Amplifier in the lower left corner. 1 page, 993K gif image.
Gonzo Cathode Follower OTL Amp from 1951 - An article from the Nov. 1951 issue of Electronics magazine. Massive overkill design for 6 watt output. Check out the four 872A rectifiers in the power supply! There are comparisons against various output transformers. Also here are letters to the editor on this article. Article: 4 pages 621K pdf format, Replies: 2 pages 182K pdf format.
Tubes or Transistors? - An article from April 1959 Electronic Industries that gently reminds readers of the benefits of tubes in the midst of the pro-transistor frenzy. 6 pages, 891K pdf format.Ampex Ultra High Fidelity Tape Recorders - a 16-page brochure from the early 1950s that covers the model 300 and 400 Ampex tape recorders, as well as their variants. Explains to the semi-technical decision-maker why Ampex is so good. Due to the multi-color, detailed presentation, the file is large (6.8Mbyte pdf).
Ampex AG-440 Brochure, Jan. 1967 - covers the original AG-440-1, -2, -3, and -4 tape recorders as well as the AG445 playback-only version. (3.2Mbyte pdf)
Ampex AG-440-8 Brochure, Dec. 1967 - describes the first AG-440 8-track. References previous AG-440 brochure. (627K pdf)
Ampex AG-440 price schedule A159, Feb. 1967. Covers AG-440-1, -2, -3, -4, AG-445 variants, and accessories. (732K pdf)
Fairchild 670 Compressor - the classic 1950's unit. This schematic was supplied by Chris Jenrick, and was recreated from the original.
Ampex AG-300 Tape Recorder Brochure, April 1967. Describes the solid-state version of the venerable 300 (2Mbyte pdf)..
How to Build a "Junkbox" Electric Guitar - an article in the Nov. 1939 Radio-Craft magazine by Frank E. Chambers, W9BMN on building a guitar amp using push-pull '45s. Also shows how to build the magnetic pickup. (362K pdf)
The 2B6 - A Duplex Triode - an article in the Sept. 1933 Radio-Craft by L. Van Der Mel about the class A2 triode as an output stage. (553K pdf)
Quality in Audio Amplifiers - an article in the Sept. 1933 Radio-Craft by W.H. Hollister about amplifiers using the 2B6. Shows a bi-amp system, too. (320K pdf)
Designing and Constructing Direct-Coupled A.F. Amplifiers, Part I and Part II - articles in the August and September1933 issues of Radio-Craft by L.M.Barcus showing various direct-coupled circuits (359K, 443K pdfs)
Engineering Features of the UX-245 - an article in the July 1929 Radio Broadcast by F.H. Engel on how to best use the new type '45 power triode.(360K pdf)
A High-Power Output Tube - The 250 - an article in the March 1929 Radio Broadcast by K.S. Weaver on the design issues that led to the development of the '50. (418K pdf)
Note: the following articles (in brown) were scanned from magazines borrowed from Mark Rauber of Gardnerville, Nevada:
What Is the Best Loud Speaker, and Why? - an article by H. Winfield Secor in the March 1927 Radio News about speaker theory for the radio listener. Check out the 20 foot Orthophonic phonograph on the first page! (908K pdf)
A Simple Roll-Type Loud Speaker - an article by E.M. Yarbrough in the July 1927 Radio News. Remember the lineanum tweeter? This looks like the same thing. (215K pdf)
A Three-Foot Roll-Type Loudspeaker - an article by Clyde J. Fitch in the February 1927 Radio News on another lineanum-type speaker (252K pdf)
Chemical Condensers of Large Capacity - an article by Clyde J. Fitch in the August 1926 Radio News. How to build your own electrolytic capacitors. (394K pdf)
Tubes Within Tubes - an article by G.C.B. Rowe from the July 1926 Radio News on Dr. Siegmund Loewe's multi-section tubes, from Germany. These were truly the first integrated circuits, since not only triodes, but passive components were enclosed in the vacuum tube. (558K pdf)
New Radio Devices of Fixed Precision - an article from the July 1926 Radio News on some more of Dr. Loewe's inventions: metal-film resistors and visually-indicating quartz crystals. These crystal indicators were used by the Germans in WW2 to calibrate their field and aircraft radios. (463K pdf)
The following series of articles written by Sylvan Harris give a good overview of 1920's amplifier design. Unfortunately, not all sections of this series are available.
"MotorBoating," What It Is and Why - an article by O.D. Westcott in the August 1927 Radio News on the sporting proclivity of resistance-coupled amplifiers. (416K pdf)
Some Aspects of High Quality Reproduction - two articles by Paul Traugott on what contributes
to high quality reproduction in radios:
Part
I - the RF and detector contributions
- July 1927 Radio News (318K pdf)
Part
II - the AF amplifier contribution -
August 1927 Radio News (289K pdf)
Advancements in R.F. Stabilizing Systems - an article in the May 1927 Radio News about methods in stabilizing triode RF amplifiers in radios - a problem that would become moot within a few months with the introduction of the screen-grid tube. (314K pdf)
The Browning Drake Receiver - several articles on a popular radio receiver design of the 1920s - a neutralized triode RF amplifer followed by a triode regenerative detector, then two or three audio amplifier stages.
An A.C. Phonograph Amplifier - an article by James Millen in the Jan. 1928 Radio News about constructing a high-quality phonograph amplifer using push-pull '10s. (1.1Mb pdf)
A High Efficiency - High Quality Audio Power Amplifier - a paper by Alexander B. Bereskin given at the 1954 IRE National Convention about class-B amplifier design. Lots of circuits and ideas. 559Kb pdf.
System Design Factors for Audio Amplifiers - a paper by M.V. Kiebert, Jr given at the 1954 IRE National Convention. Detailed analysis of push-pull amplifier design. 902Kb pdf.
Active Bandpass Filter has sharp cut-off - an article from the Aug. 15, 1958 Electronics magazine by J. Ross Macdonald about a tube-type 7th-order high and low pass filter. Offers ideas for active cross-overs as well as interesting techniques for reducing distortion by reducing heater voltgage. 611K pdf.
Acrosound Transformer catalog from 1955- has interesting push-pull amplifier circuits, too. 1.5 Mb pdf
"The
Williamson Amplifier", reprints from Wireless
World magazine on the Williamson amplifier. The articles range
from 1947 to 1952. This is the original British booklet, not the
reprint by Old Colony, so the advertisements are the original
British ones. 3.4Mbyte pdf
Newark Radio 1937 Ham Radio Flyer - This is an 8-page catalog from Newark Radio in Chicago geared for ham radio customers. It gives a nice snapshot of the radio art in 1937. 8.2Mb pdf
