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From the Tubemuseum Vaults - A REAL Archeological find ... NOS Telefunken CCa with VERY RARE "O" Getter with Gray Electro-Static Shield-Plates.
CCa Telefunken West Germany 1960's "Excellent neutral holographic soundstage, vast vocabulary of tone Establishes remarkable layers of harmonics, very rare"- quote from the tubemuseum review.
Audiophiles vote these as the best-sounding top-rated Frame-Grid Construction CCa. These tubes are known for excellent performance, smooth highs, inner detail and overall resolution and balanced sound. Revered by many as one of the MOST DESIRABLE CCa - the HOLY-GRAIL of the E88CC family and one of the MOST DESIRABLE CCa. CERTIFIED ULTRA-LOW-NOISE PHONO-GRADE SPECIMENS - Manufactured in Ulm Germany almost half a century ago! Low Noise CCa - THE BEST!
CCa = LOW-NOISE E88CC "6922" = PREMIUM QUALITY GOLD PIN E88CC:
The "CCa" is an E88CC specially selected for "Post Germany" in the 1950's -70's, they were a special low noise, low microphonic, long-life E88CC / 6922. Philips had similar "designations" for the "Dutch Post", some tubes that were selected had "PTT" * and "BP" lettering or etched designations, but they were the same as a top specification E88CC. The "German and Dutch Post" consisted of telephone, telegraph, telex, and the postal system "tube" technologies which required LOW-NOISE E88CC / 6922. A CCa is the same as a 6922 but was tested and certified with high mA, RP, and Mu and lowest-noise audio threshold - the same proceedure the Tube Museum New York certifies tubes by today. Much of the telephone centrals used vacuum tube technology equipment for telephone equipment requiring a "noise-free" enviroment. The letters "CC" probabably equates to "double triode", and for a special low-noise design - the "frame-grid" inner construction, which was actually invented by Amperex USA, and became ubiquitous - Present, appearing, or found everywhere in the 6922/E88CC design of the day, including Telefunken, Siemens, Amperex, Philips, and many others. Internally the inner construction of the Telefunken CCa is identical to Siemens Halske E88CC - why? Because the only difference is the cosmetic-lettering and ofcourse the "special selection" of the best and quietist specimens. In addition, the suppliers of the day, wanted a sure method of identifing the tubes they provided, as the very tubes sold to these companies. It could have been very easy to swap with a current different E88CC in the day, if it wasn't uniquily labeled, simply by walking down to the local radio shop and purchasing a different tube. The CCa factory markings identified the original supplied tubes as the ones guaranteed by the Siemens "Klingarm" Division ( "Klingarm" is the term for low microphonics. You often see Telefunken EF12K or AC701K, the K means Klingarm) whom charged a premium for selected low-noise high mA specimens for industrial customers.
* Pneumatic tubes controlled by vacuum tube amplifiers (or capsule pipelines or Lamson tubes; also known as Pneumatic Tube Transport or" PTT" in the 1950's-60's PPT systems were vacuum tube controlled) In the 1960s, Lockheed and MIT with the United States Department of Commerce conducted feasibility studies on a vactrain tube powered by ambient atmospheric pressure and "gravitational pendulum assist" to connect cities on the East Coast of the US.
From the Tubemuseum Vaults - A REAL Archeological find
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