Two Matched 1924 De Forest DV-2 Isolantite Audion Tubes
Two Rare 1924 De Forest DV-2 Audion Tubes, Matched in Gain, with Isolantite Ceramic Bases
Introduction:
The photo of Dr. Lee de Forest in the collage pict.7 is taken from ref.1. I decipher his hand-written dedication as: "To Thomas A. Edison Your genuine Admirer Lee de Forest". Did he try to correct himself, since De Forest alledgedly (ref.2) claimed to be the inventor of the electron tube? 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), but should be considered as inventor of the vacuum tube. 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. Another Edison De Forest connection is worked out in ref.4: After the sinking of the Lusitania by a German submarine on May 7, 1915, Thomas Woodrow Wilson created a civil "Naval Consulting Board" to develop new weaponry and defense, whose president became Edison with distinguished members like
L. H. Baekeland, President of the General Bakelite Company, and later physicists and future Nobel laureates Arthur Compton and Robert Millikan, and Lee De Forest, working especially at an electronic submarine sound detector.
About the DV-2 Tube:
The history and technology of the DV series of De Forest audion tubes is described in ref.3. The "V" refers as usual to the short (4) pins of the tube, the number originally (DV-1 and DV-6) to the filament voltage. The original version of the 1923 nickel based DV-2 was changed in April 1924 to have a ceramic "Isolantite" base, which again was discontinued in November 1924 in favor of a bakelite base. The DV-2 can in almost all cases be replaced with an ordinary UV 01A tube.
For the historians only: 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 DeForest-Crosley radios in Canada. The DeForest-Crosley brand now becomes managed by Rogers-Majestic and all De Forest-Crosley radios now carry a Rogers-Majestic serial number.
Here are the specifications:
Technical Description of Item
Manufacturer
De Forest Radio Telephone and Telegraph Company, Jersey City, N. J.
Model
DV-2 Audion
Type
1923 DC heated triode with 5 Volt 0.3 Amp filament
Production Year
Isolantite version between April and November 1924
Substitute
Type 01A tubes
Dimensions (WxDxH)
4" x 1½" dia., short pin
Comment
Two collectible and usable early matched radio tubes, especially fitting early De Forest sets
About my tubes:
I found the tubes inside a 1924 De Forest-Crosley Trirdyn regenerative receiver, sold in a separate auction. The tubes happen to be a perfectly gain-matched pair, as picts. 5 and 6 demonstrate. Whereas matching got vital in later push-pull audio amplifier stages, it may be of importance in early radios, where volume is controlled by varying filament voltages of more than one tube.
Here I sell two collectible and working early type 01A De Forest DV-2 audio tubes, tested good and to match in conductance on a 1 percent level
Gallery: (watch descriptive legends under pictures - and go to my scripted Supersize Gallery)
Description
Shipping and Handling
Box Size (WxDxH)
about 6 " x 4" x 3 "
Box Weight
about 0.4 kg = 1 pound
Senders Postal Code
Canada V6A4B3 or USA 98281
Costs to Canada (Expedited)
typical C$ 10.- but varies
Costs to USA (Expedited Parcel Post)
typical US$ 6.- but varies
Costs International (International Parcel)
typical US$ 7.- but varies
Handling
no handling fees
1 C$
about 0.82 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.
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 Français.
Disclaimer
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.
Note:
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.
