Heintz and Kaufman


This entry is dedicated to the Heintz and Kaufman manufacturing business.

Start-up[edit | edit source]

In 1922, Ralph Heintz and Mr. Kohlmoos were selling radio parts at 217 Natoma St. in San Francisco. QST November 1, 1926 and Radio Magazine September 1925 shows Heintz and Kohlmoos manufacturing tuned-plate tuned-grid sets. The 1925 edition White's Callbook shows AM station KFPV licensed to Heintz & Kohlmoos, San Francisco, CA at 236 M (1270kHz) for 50W, however, anecdotes suggest this station was never on-air.[1]

Heintz "moved-on" from his association with Mr. Kohlmoos sometime after 1925 and by 1936 the tube business was far more profitable than selling ham parts, if he could find a way to compete with RCA and other tube manufacturers.

Heintz and Kaufman was operated by Mr. Ralph Heintz and Mr. Jack Kaufman. The first address shown for H&K is 219-221-223 Natoma street in San Francisco and in May 1936 ran a full page advertisement for a kit of parts for building "The Ideal Ham Set" designed by Gerald M. Best also in the same magazine. It used conventional triodes, not tubes made by H&K.

An advertisement in the May 1927 Radio magazine showing their logo and addresses as 219-221-223 Natoma Street, San Francisco.[2] That is South of Market Street, noting the 200 block of Natoma is gone now.

The San Francisco manufacturing registry for business in 1936-37 shows: Heintz & Kaufman, Ltd., Radio Apparatus, Wireless Equipment, 311 California Street, San Francisco[3] and this was the address of the Robert Dollar building. The Robert Dollar corporation acquired a controlling interest in the Heintz & Kaufman business as will be shown later.

South San Francisco was home for the H&K factory in the 1930's, it was located adjacent to the DuPont paint factory. South San Francisco today is still known as "The Industrial City" and a large signage exists along the hillside of Mt. San Bruno which separates South San Francisco from the neighboring San Francisco City and county.

Heintz & Kaufman's success in making vacuum tubes spawned the launch of Eitel-McCullough and ultimately the birth of Silicon Valley.

Heintz and Farnsworth demonstrating a new tube
Demonstration of cold cathode vacuum tube

Ralph Heintz demonstrated an interesting device designed by Philo Farnsworth, a "Tube without a filament or grid!" and it seems unrealistic to be able to deliver much power with any reasonable efficiency, but it was claimed to work. A picture of Heintz demonstrating the device to Dr. Frederic Terman and others is shown on the cover of the Oct. 1934 Radio and Shortwave Experimental Magazine, any copyright is acknowledged.

The H&K firm has a rich history of manufacturing aeronautical radio transmitters and receivers and a rare facet that H&K supplied transmitters used for conveying the AC generator status from the generating stations located on the Feather River in Northern California back to the Bay Area control room for the power company (PG&E), which is documented in the Leonard Fuller oral history.

The following was from personal material given to Mr. Marshall Loring of Eimac, he was the last manager of the "Eimac'ers Retiree Gatherings" which ceased shorty before he moved to Tennessee.

In the materials was a great photo of the Heintz Kaufman factory signed by one of the employees dated 6/7/1935. It was presented to one of the employees in the photo, Mr. Irv Coutts.

Archival photo provided by Ginny Coutt's, shows the staff at the H&K Plant in 1935. It is from a private collection.

Along with the photo was a lengthy letter describing the life of that employee, Irv Coutts, by his wife whom he later met at Eimac. Its all very touching to read her description of their meeting, getting married and working in the same place. That letter and photograph is reproduced here with permission.

Archival material supplied by Mr. Coutts' wife Ginny included a photo of the Heintz and Kaufman staff in the South San Francisco factory.

The following is inscribed on the photo of the Heintz and Kaufman team:

"Best Wishes to Mr. I. M. Coutts from Henry Guccuhagen (sp?) 6/7/1935"

Additional notes by Ginny Coutts: "South City before Eimac.

First row 2nd O.P. Taylor, 3rd Irv Coutts, 2nd row 4th George Wunderlich"

(Front row 6th from left is Ralph Heintz (wearing white shirt with tie).

note: Bill Eitel joined H&K in 1929 and Jack McCullough followed in 1930 and both men left H&K in 1934, the year before this photo was taken.[4] O.P. Taylor and Irv Coutts would later become Eitel McCullough employees in production and George Wunderlich became Eitel McCullough's general manager in Nov. 1944.


From 1915 to 1917 Ralph M. Heintz was in college, first at U.C. Berkeley then Stanford Univ. When WW1 broke out he enlisted in the U.S. Army Signal Corps Aviation Section. After 1918 he returned to Stanford where he graduated with a degree in Chemical Engineering in 1920. [5]

In May of 1922, at the age of 30, Heintz was the upstart chief engineer of KFDB, a radio station operated by a Bank in San Francisco. Heintz and his staff built a transmitter using a 50 Watt exciter followed by a 1500 Watt linear amplifier, the first known application of a linear amplifier in the final stage by any broadcast station at that time. The station was plagued with problems and shut down after having been in existence just over a year. As John Schneider says on his webpage theradiohistorian.org: "These (stations) weren't like the stations we know today; rather, they stood with a foot in the world of broadcasting and a foot in amateur radio"[6] thanks to John for documenting the history of many small broadcasting stations in the budding years of broadcast. He based some information on Ralph Heintz's writings from his archives.

Amateur radio connections[edit | edit source]

Like many of the engineers, craftspersons and technicians of his era, Ralph Heintz was an avid radio amateur.

W6RH QSL card from 1960.

What tales his QSL card could tell! But there is no proof that Ralph Heintz was licensed 6XB, more likely he operated as a student from the club station 6XB at UC Berkeley. (The University of California Amateur Radio Club Berkeley was licensed as 6XB in 1914, as 6BB and 6XM in 1920, and is still active under the calls W6BB and NU6XB).

There is a rich history of Ralph Heintz being licensed with numerous calls at various times.

The first was as 6AUQ in 1921 while he lived at 653 Miramar Ave. in SF then in 1924 as 6GK at 119 26th Ave, SF, then in 1926 as 6XBB (portable) at the same address.

The 1928 callbook shows 6GK still assigned to Ralph and his wife Sophie was licensed 6GI.

W6XF was an experimental license issued to the Heintz and Kaufman Co. in 1936-1937 for portable operation and W6XBB was an experimental license issued to Ralph in San Francisco then finally, in 1959 Ralph was relicensed as W6RH, Sophie as W6SH. Thanks to Friedrich Sommer, K6EE for this research.   

Of many radio amateurs working for Heintz and Kaufman were the very notable pair, Bill Eitel and Jack McCullough who both left H&K in 1934 to form Eitel McCullough Inc. (ultimately EIMAC) and eventually became very successful when the US Government needed special electron tubes to support technology developed during WW2, especially early radar systems.

Shown in the 1935 archival photo is Irv Coutts, W6HTR, whose wife Virginia supplied the photograph. Additional photos and history of these two employees are included in the ethw eimac wiki.

Norm Wilson, N6JV, has an extensive collection of tubes including many rare examples made by Heintz and Kaufman. He covers the rare gridless HK54 Gammatron[7] and has an excellent website with detailed information and photos of gridless Gammatrons.[8]

An account of Ralph's miniature railroad on his property on the San Francisco Peninsula is well documented and includes info on his estate.[9]

RCA[edit | edit source]

The late 1920's was a busy time with new technologies popping up around developments in radio communications. Thanks to Lee DeForests' inventing the vacuum tube there were numerous firms (on the East Coast USA) manufacturing diodes, triodes and tetrodes for receiving and transmitting equipment all under the DeForest's patent protection which later became property of RCA.

The Radio Corporation of America rose rapidly after its creation in 1919 to become one of the largest manufacturers of radio receivers and transmitters; the sales of vacuum tubes were a major profit source for RCA so they vigorously enforced and defended their patents.

Ralph Heintz circumvented RCA's patent issues by developing a tube that did not use a grid of the conventional type which allowed electrons to pass through it on their path to the anode. His design used an electrode that deflected electrons onto or away from the anode. This technique proved to be far less efficient than a conventional triode but it was a working solution.

Being a chemical engineer, Heintz probably lacked much of the formal knowledge in the field of electrical engineering but in those days an experimental approach was often employed; taking a conceptual idea to making a prototype with little or no mathematical analysis, the so-called empirical or "cut-and-try" method succeeded in making many working products.

With but a few exceptions, there is no record of the employees hired to work at H&K other than anecdotal information but the staff there had to be very diversified and multi-skilled, manufacturing electron tubes in the same plant where transmitters and receivers were assembled was quite an accomplishment.

Patents[edit | edit source]

H&K filed with the US patent office on Feb 20, 1929, just 8 months before the Great Depression, for the trademark GAMMATRON and it is interesting to note the address used, 311 California St. in San Francisco. That was the headquarters of the Dollar Steamship Corporation which became one of H&K's largest customers and the Robert Dollar Co. ultimately acquired a portion of the H&K business. The H&K Trademark was reassigned twice to the Robert Dollar Co. of San Francisco, first on Nov. 1, 1949 then again Sept. 30, 1950.

RCA eventually sued Heintz and Kaufman over alleged patent infringement and when faced with H&K's strong defense with Frederick Terman ScD, the respected Stanford University professor of Electrical Engineering on their side, RCA withdrew their case.[10] This allowed H&K to continue manufacturing Gammatrons as well as conventional triodes.

H&K employed Ralph C. Shermund. Mr. Shermund had worked for Federal Telegraph Co. in San Francisco where he patented an important receiver development, patent 1,898,792 filed October 28, 1929.

Later, Shermund's patent 2,093,492 Sept. 21, 1937 (application dated Oct. 21, 1935) among others, was assigned to H&K for making glass-to-metal seals, a critical component in manufacturing glass-envelope vacuum tubes. In 1933 Shermund was chairman of the San Francisco section of the Institute of Radio Engineers, Inc. and his affiliation with H&K certainly carried some prestige to the firm.

Dollar Steamship Co[edit | edit source]

HK dollar reference.jpg

Any discussion of Heintz & Kaufman would not be complete without including their affiliation with the Dollar Steamship Co, ultimately becoming a division of The Robert Dollar Co! H&K equipment was used aboard the SS Kaimiloa with call sign KFUH when, in April 1925, it made the first coherent shortwave radio contact from a ship (previous contacts were long wave and were using spark technology). A story with a picture of a KFUH QSL card is here.[11]

As a result of successful communications with the SS Kaimiloa, a personal schooner that roamed the South Seas, in 1927 the Dollar Steamship Co. began equipping all of their many ships with Heintz and Kaufman shortwave radios. A great resource of information on the Dollar company and the Heintz and Kaufman relationship can be found at the radiomarine.org website.[12]

Heintz and Kaufman also developed specialized transmitters and receivers that were fitted to aircraft, a totally new field at that time. H&K radios were carried on expeditions to distant places including admiral Richard Byrd's polar expeditions. The Perham foundation lists some of these accomplishments in their synopsis on Ralph Heintz.[13]

Press photo dated 8/25/1937 On rear: "Norma Ghaddi of Heintz and Kaufman gives idea of the simplicity of radio operation with the new devices perfected for the Dollar Boats" .

The use of direction finding equipment, or beacon equipment for Dollar (Lifeboats) looked to be part of the H&K suite but were never fully implemented into the six ocean liners that Dollar commissioned, only two ships were completed because of continued decline in the economy that began with the Great Depression and the Dollar Co. was bankrupt in 1938 and the once-great shipping company was taken over by the U.S. Maritime Commission, later to be reincarnated as the American President Lines.[14]. See photo to the right of an emergency transmitter built by H&K intended for use in the ships.

EIMAC[edit | edit source]

Of many radio amateurs working for Heintz and Kaufman were the very notable pair, Bill Eitel and Jack McCullough who both left H&K in 1934 to form Eitel McCullough Inc. (registered trademark EIMAC) and eventually became very successful when the U.S. Government needed special electron tubes to support efforts during WW2 (see Eimac wiki). Most notable was the VT-127 tube developed for the SC air-search radars used at sea. Both Eitel McCullough and Heintz & Kaufman manufactured these, as did other firms as shown on n6jv's webpage.

Several other radio amateurs employed at Heintz and Kaufman eventually were employed by Eitel McCullough. These included Jim Brown, W6AY, who was head of tube manufacturing at H&K and retired from Eimac in 1975 and Al Clark, W6MUC, who built receivers at H&K. Both men and others were involved with making the first 1296MHz Earth-Moon-Earth communication by radio amateurs in July 1960 when Eimac was a division of Varian Associates. The Eimac radio club still holds FCC license W6AY.

Irv Coutts[edit | edit source]

Irv Coutts and several other H&K employees left to go to work for Eitel-McCullough Inc. in 1940 since they were rapidly growing and hiring to support new electronic technologies being developed for WW2. Irv Coutts, W6HTR, ultimately retired from Eimac in 1985 after 50 years of working in the tube business. File:HK Ginnie Coutts notes.pdf Irv Coutts is the subject of the attached documentary by his wife whom he met as a co-worker at the San Bruno Eimac plant.

Bill Eitel (left) with Irv Coutts (right), receiving the Eimac 40th anniversary pin award.

Power Line Carrier Systems[edit | edit source]

An interesting application for Heintz and Kaufman transmitters was in the so-called carrier-current transmission whereby high voltage power transmission lines carry information from a generating station to a central control point many miles distant. Information on H&K's transmitters employed for this is discussed in Leonard Fuller's oral history.

Heintz and Kaufman go separate ways[edit | edit source]

Jack Kaufman left H&K in 1946 and, together with Garrett Lewis, started a tube company under their names Lewis & Kaufman, using the Lewis Electronics site located in Los Gatos, CA.[15]

US Navy NAVSHIP advice regarding the use of H&K tubes at sea.

During their productive period Heintz and Kaufman competed with Eitel McCullough, manufacturing triodes including the 304TH and 304TL but the US Government disallowed use of some H&K triodes in military equipment due to reliability problems (refer to attached US Navy NAVSHIPS advice).

In 1950 H&K introduced a pentode designated type 257/4E27. Eitel McCullough had already produced a similar tube as type 4E27/5-125B. These were used in a push-pull pair in type AM-14/APT amplifiers manufactured for the US Army and US Navy. Covering the 85-150MHz frequency range, the compact amplifiers were used as airborne radar jammers. H&K had finally moved up to the VHF bands but the end was near. Without further R&D taking place, H&K withered away in 1953 while the Eitel McCullough operation took the lead as it developed ceramic power grid tubes capable of operating at UHF and microwave frequencies.

Ralph Heintz partnered with Bill Jack, a Cleveland OH native, and they started Jack and Heintz Co, JAHCO, manufacturing airplane parts in Maple Heights, OH. From 50 employees in 1940 it grew to 8700 employees in 1944. Precision Products bought them out in 1946 and made both men millionaires. Heintz continued as VP until May 31, 1948 when he stepped down but continued to do R&D. [16]

A detailed history of Jack and Heintz Company is at the ieee.org entry: Jack and Heintz

An advertisement in Radio News Feb. 1948 p.82 shows an adjustable dipole antenna made by Heintz & Kaufman's "Communications Equipment Division" at 50 Drumm Street, San Francisco, CA.

Fine Art Mural[edit | edit source]

In his painting done in 2002 titled "Electronic Device Pioneers of Silicon Valley (1906–1939)"  artist Robert K. Semans shows Ralph M. Heintz (seated) with Bill Eitel and Jack McCullough (standing) on the right side of the 9 x 18 ft. canvas. The background is near the Eastern arch of the Stanford University quadrangle.

Logo & Trademarks[edit | edit source]

The H&K logo apparently was in use well after the company closed. Unsure who ultimately made use of the HK logo in the 60's. Another example of debauched use of a logo on modern products.

The "real" H&K Trademark was re-assigned to The Robert Dollar Co. at 311 California Street, San Francisco twice!

Early H&K Scientific logo, acknowledging moral rights, copyright and trademarks of the owners. Note the somewhat subdued "HEIKOH PRODUCTS" at the top. This may have been to show the dissolution of the Heintz -Kohlmoos business which operated at 217 Natoma Street and ended sometime after 1925. Note that H&K expanded to adjacent addresses, literally moving next door.

Invitation[edit | edit source]

While this a fresh entry, it's an open invitation to you as readers who may have historic information like photo's, letters, anecdotes and other documents to augment and capture this remarkable history. Get in touch, David k3hz@ieee.org

Further reading & Acknowledgements[edit | edit source]

Major contributions from Mr. Reid Brandon W6MTF

Norm Wilson N6JV Museum



Antique Wireless Association Review Volume #10, 1996.



References[edit | edit source]