Rare 1924 De Forest-Crosley "Trirdyn Special" Regenerative Receiver


Rare De Forest Version with Canadian Specials, of the 1924 Crosley Trirdyn 3R3 Special Regenerative Battery Receiver, in Mint and Working Condition

In 1922 the Crosley Manufacturing Corp. in Cincinatti, Ohio, founded by Powel Crosley Jr. (1886-1961) started selling low cost "Harko" crystal sets ($7.00) and audion receivers ($16.00), and one year later regenerative receivers, originally made by Precision Equipment Co. Inc., under license from Edwin Howard Armstrong (1890-1954). Soon Crosley, "The Henry Ford of Radio", using car industry mass-production concepts, made 5000 sets per day, at his new Crosley Radio Corporation in Cincinatti. In 1924 Crosley bought the majority of the De Forest Radio Corp. Ltd. of Canada, opening him its large patent pool (including RCA licenses), and in late 1925 the American Radio and Research Corporation AMRAD, a broadcasting station in Medford Hillside near Boston, Massachusetts, which also owned a neutrodyne license. The same year Edward Samuel ("Ted") Rogers (1900-1939) established "Canada's First Rogers Batteryless" (CFRB) in Toronto, and in 1928 the Rogers-Majestic Corporation, which 6 years later took over De Forest-Crosley (see also my auction for a 1935 Rogers-Majestic TEN-60 Cathedral Radio).

About the Trirdyn Regenerative Receiver:
The 1924 Trirdyn 3R3 Armstrong regenerative type set with two-tube audio amplification, contains three tubes of type 01A (12A and 71A would work too). It is battery powered - as first AC-powered Rogers sets were coming up one year later, the cabinet is from solid mahogany, with a bakelite front panel. The set's name Trirdyn (slogan "Three tubes do the work of five") may either indicate the small number of only three tubes for a fully functional TRF, or may point to the first tube's threefold purpose (pict.22): a. RF amplification, b. RF selection as an oscillator tube, c. first stage of AF amplification (by positive feedback of the detected audio signal of the second tube). The third tube is a second stage of AF amplification easily driving any high impedance horn or electromagnetic speaker. An earphone connection, disabling the last tube and the speaker, is available on the front panel. Gains of both, the detector and the AF tube, are controlled by their filament currents, which always have to be minimized, not to produce the well-known reflex howl. The Trirdyn Special is similar to a Regular Trirdyn except for a much nicer cabinet. Both, Regular and Special were also available one year later in a "Super" version with slanted front panel. My set features an additional variable mutual-inductance antenna "Loading Coil" (left in pict.2), not shown in the schematics in pict.22.
As is often the case, Canadians do it differently and mostly better than their American mother companies. The main difference between the Canadian De Forest and the original Crosley versions of the Trirdyn are the two tuning knobs, which have an integrated vernier or fine-tuning insert knob, that not only makes tuning easier but also enhances considerably the visual appearance of the radio (see pict.s 11-15).

Additional documentation:
1. http://www.leedeforest.org/
2. http://www.deforestradio.com
3. http://www.crosleyradios.com/
4. http://www.radiomuseum.org/

For the science historians only:
To demodulate an Amplitude Modulated (AM) signal some rectifying device is needed. Early Pickard type crystal radio sets had this diode effect built-in but could not tune in specific stations and had no amplification of the detected audio signal. Thomas A. Edison trying to avoid the blackening of his incandescent light bulb by the "Edison Effect" was too much an experimentalist (as opposed to a theoretician) to discover the electron (1897 by Sir Joseph John "J.J." Thomson) or at least the diode tube (1904 by Sir John Ambrose Fleming, oscillation valve or rectifier). Fleming valves and crystal detectors were used in parallel for some time. Around 1906 with his "audion" Dr. Lee de Forest introduced a third electrode between Fleming's cathode and plate, enabling amplification of the incoming radio signal. In 1912 Edwin Howard Armstrong coupled the plate of De Forest's audion back to its grid, increasing its amplification and making the tube oscillate and thereby getting frequency selective, in addition to being a rectifying device - three birds killed with one stone, the regenerative detector. Armstrong (the inventor of almost everything in radio except radio itself) patented the regenerative circuit in 1914, while he was a junior in college, the super-regenerative circuit in 1922, the superheterodyne receiver in 1918, and FM in 1933. Lee de Forest had reinvented the regenerative receiver in 1916 but unjustifiably won the resulting 12 year lawsuit against Armstrong. Power consumption of a 3-tube regenerative receiver compared to a normal 6-tube TRF or 5-tube Superhet is low, a big issue at a time where heavy batteries or heavy transformers had to be used, and even today enthusiasts favor its simplicity.

The people:
Lee de Forest (1873-1961): "Father of Radio" and "Grandfather of Television", invented the Audion (3-element vacuum tube = triode) in 1906, in 1934 established Lee de Forest, Inc., Los Angeles, Calif., was supported for Nobel Prize for Physics, but instead in 1959 received an honorary Oscar, with the inscription: "Academy Honorary Award to Lee de Forest for his Pioneer Invention which brought Sound to the Motion Picture". He owned 180 patents, but needed Edwin H. Armstrong to understand and David Sarnoff to commercialize them, married 4 times. At the age of 80 the inventor asked reporters: "Why should anyone want to buy a radio ... nine tenths of what one can hear is the continual drivel of second-rate jazz, sickening crooning by degenerate sax players, interrupted by blatant sales talks?" Sounds familiar? In February 1934 Edward Samuel Rogers Sr. acquired one of his principal competitors, Consolidated Industries, which manufactured De Forest-Crosley radios in Canada. The De Forest-Crosley brand now becomes managed by Rogers-Majestic and all De Forest-Crosley radios now carry a Rogers-Majestic serial number.
Powel Crosley (1886-1961): together with business savvy brother Lewis made money with gadgets, and from 1921 on with radios, after his son wanted one, by 1924 became world's largest radio manufacturer, participated in fishing tournaments, owned Nikassi Island in Canada and Bull Island off the coast of South Carolina, and many houses. Crosley not only made radios, but also refrigerators ("Icyball"), bought the Cincinatti "Reds" baseball team (Crosley Fields), made compact cars, and popularized early TV.
Edwin Howard Armstrong (1890-1954): invented the "regenerative receiver" in 1913, later sold his superheterodyne patent to the Radio Corporation of America (RCA) who used it to monopolize the market for this type of receiver until 1930, thereby ousting Tuned Radio-Frequency (TRF-) receivers. Armstrong, who also was the inventor of FM in 1933, in grief and despair after being abandoned by his wife of 31 years, Marion (she was the secretary of the president of RCA, David Sarnoff) and tired from his life-long legal patent battles jumped from the window of his 13th-floor apartment in New York on Jan.31, 1954. He was inducted into the National Inventors Hall of Fame in 1980.

Here are the specifications:

Technical Description of Item
Manufacturer De Forest Radio Corporation Ltd., Toronto Canada
Model Trirdyn Special
Type 3-tube battery powered regenerative reflex receiver
Production Year 1924
Serial Number C 2204 R
Cabinet Solid walnut, low rectangular case, bakelite front, lift top
Dials and knobs 2 bakelite tuning dials, 3 bakelite knobs for amplifier, feedback and detector controls
Frequency Range 550-1500 kHz standard broadcast
Controls 2 x tuning, volume, feedback, and detector controls, on/off
Tube line-up RF & 1stAF, Detector, 2ndAF, 3 matching engraved Cunningham CX-301A, globe shape
Dimensions (WxDxH) 23½" x 12½" x 8½"
Weight 16½ lbs
Comment Historical and technical icon of pre-superhet radio development with Canadian specials

About my radio:

The radio is in excellent visual and electronic condition with no missing or additional parts, no chips, dents or offending scratches. The radio works perfectly as seen in the flash movie (clicking pict.28), using three engraved Cunningham CX-301A globe tubes, included. When I bought the radio, I found in it two original 1924 De Forest DV-2 audion tubes, the De Forest version of a 01A tube (pict.21). Since I don't have a third one and since the two are exactly matched in gain, I decided, to sell them in a separate auction. The movie was taken with the test setup in pict.26, using a single 67.5Volt battery, replacing both, the 22.5Volt and the 90Volt "B" batteries, and a single 6Volt battery (4 D-cells), replacing both, the "A" and the "C" batteries. The 67.5Volt battery (pict.27) is a development by the seller, to be commercialized lateron, and is not included in the auction. Also not included are the RCA 103 speaker (pict.8), used for the movie, which is sold together with my Radiola 60 , and the headphones (pict.s 1-5).

This auction is about an early very successful radio concept, the pre-superheterodyne regenerative reflex receiver. The incarnation on auction here is considerably enhanced over the original Crosley 3R3, by being the Special version and the Canadian De Forest version with extras, and having an additional antenna "Loading Coil". It is in mint condition and can be made working with a minimal set of batteries

Gallery: (watch descriptive legends under pictures - and go to my scripted Supersize Gallery)


Shipping and Handling
Box Size (WxDxH) about 26" x 16" x 12"
Box Weight about 9 kg = 20 pounds
Senders Postal Code Canada V6A4B3 or USA 98281
Costs to Canada (Expedited) typical C$ 27.- but varies
Costs to USA (Expedited Parcel Post) typical US$ 42.- but varies
Costs International (International Parcel) typical US$ 84.- but varies
Handling no handling fees
1 C$ about 0.83 US$
On request I ship to US and international destinations out of Point Roberts, WA, ZIP 98281. I charge a fixed fee of 10US$ for this service, because I have to drive 30 miles and pay 5US$ cross-border fees. Shipping costs are cheaper by almost a factor of two compared to CanadaPost. You can calculate shipping costs for this item yourself by using the shipping calculator of CanadaPost or of the US Postal Service, the box size and weight data in this table and your own zip-code. Shipping within Canada will be done as before through CanadaPost, the next business day after arrival of the money. Of course I combine shipping when possible.
Payment Preferences (priority ordered)
I prefer Money Orders
Take Cash for pickup items
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Return Policy and Contact
I am convinced of the sound quality of my offers and strive for professional handling and therefore accept returns. I accept a return if the item was damaged from shipping and the buyer payed for insurance against damage. I also accept a return, if the condition of the item differs significantly from the one listed in the auction and the difference was not caused by shipping damage or unprofessional unpacking. In this case I request a short but complete notification of defects by e-mail prior to shipping back. The buyer pays for the return shipping and handling costs and gets refunded for the bid price. Please send me an e-mail in case of any additional questions. Ich spreche Deutsch. Je parle Franšais.
I disagree with many of my radio restoring colleagues by saying, there is no reason, why these radios should not be used as any other radio. They were built for 24/7 and they should work so. All my radios have been subject to a 48 hour continuous burn-in test, which they survived unscathed. I do not, however, give a guarantee against possible future malfunctioning, although I am ready to help solve problems, by giving remote diagnostic assistance and repair advice as well as supplying parts. I also decline any responsibility for consequential damage or bodily harm, caused by operating the devices without taking proper precautions. Safety standards were much softer 50 years ago, than they are today, and the radios worked with elevated voltages and temperatures, compared to today's radios.

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EBay's restricted policy to use Javascript eliminated the useful and harmless image attribute style="width: ekspression (document.body.clientWidth/2)" [disguised], which allows resizing pictures to any client screen and in case of a browser resize. The feature is still available in my Supersize Gallery. I tried a preliminary workaround. It works in Netscape7+ and in IE6+, the latter however requiring manual refresh after resize. Any comments very welcome.


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