6V6

The 6V6 pinout, metal versions had the shell connected to Pin 1

The 6V6 is a beam-power tetrode, introduced as the 6V6G by Ken-Rad Tube & Lamp Corporation in late 1936,^[1] it is still in use in audio applications, especially electric guitar amplifiers. Following the introduction in July 1936 of the 6L6, the potential of the scaled down version that became the 6V6 was soon realized. The lower-powered 6V6 was better suited for average home use, and became common in the audio output stages of "farmhouse" table-top radios, where power pentodes such as the 6F6 had previously been used. The 6V6 required less heater power and produced less distortion than the 6F6, while yielding higher output in both single-ended and push-pull configurations. Although the 6V6 was originally designed especially for use in automobile radios,^[2] the clip-in Loctal base 7C5,^[3] from early 1939, or the lower heater current 12V6GT, both with the identical characteristics to the 6V6, but with the smaller T-9 glass envelope, soon became the tubes of choice for many automotive radios manufacturers. Additionally, the 6V6 had applications the portable radio market.

The data sheet information supplied by the tube manufacturers design centers, list the typical operation of an audio output stage for a single 6V6 as producing about 5W of continuous power, and a push-pull pair about 14W. Amplifier manufacturers soon realized that the tube was capable of being used at ratings above the recommended maximums, and guitar amplifiers with 400V on the plates of a pair of 6V6GTA claim to produce an output power of 20W RMS at 5%THD with 40W Peak Music Power, and with 490V on the plates, as much as 30W RMS.

History

Various 6V6's manufactured around the world; from left to right – 6V6GTA by General Electric, 6V6GT JAN National Union (1940s), 6P6S (USSR, 1978) and modern production 6V6GT by Electro-Harmonix.

Following the 6V6G, RMA Release #96 – 09 Nov. 1936, sponsored by Ken-Rad Tube & Lamp Corporation, with the ST shouldered glass envelope, the 6V6 was announced with a metal mantel in January 1937 by Hygrade Sylvania.^[4] The RMA Release #125 – 03 Jan.1938, Sponsored by RCA. for the 6V6 tube has led to some confusion as to the origins of the 6V6. The 6V6G but not the 6V6 is in the RCA manual RC-13 from July 1937. Tube manufacturers were promoting the superiority of metal tube designs in the second half of the 1930s, and this tube, having been introduced during that period, was produced in large quantities in this format. The introduction of the 6V6GT, RMA Release #201 – 10 July 1939, was sponsored by Hytron Corporation. By 1940, the 6V6 was mostly being produced in this smaller "GT" T-9 glass envelope.^[5] The 6V6GTA – RMA Release #1681 – 2 July 1956, sponsored by Hygrade Sylvania Corporation, has a controlled warm-up period.^[6]

Current use

Generally speaking, 6V6 tubes are sturdy and can be operated beyond their published specifications (the 6P6S, which has poor tolerance for out-of-spec operation versus most American and West European-made 6V6 variants, is an exception).^[7] Because of this, the 6V6 became very popular for use in consumer-market musical instrument amplifiers, particularly combo-style guitar amps such as the Fender Champ, the Gibson GA-40, and the Fender Princeton Reverb, and Fender Deluxe Reverb amps, which run a push-pull pair of 6V6s at 410V-plus on the plates. This market allows Chinese, Slovakian and Russian tube factories to keep the 6V6 in production to this day. Because of the relative similarity in voltage and characteristics between the 6V6 and the popular EL84/6BQ5 power pentode tube, several electronics and musical instrument companies have developed adapters to allow an amplifier with 6V6 octal sockets to accept the miniature noval pinned EL84 tube. However, no reverse adapter, that is to allow a mini-noval EL84 socket to accept a 6V6, has been developed.

The 6V6 Family and equivalents

6V6G – Glass "Shouldered Tube" ST envelope.

6V6 – Metal jacketed envelope.

6V6GT – smaller "Glass Tube" T-9 envelope.

6V6GTA – with a controlled warm-up period.

6V6GTY – a GT with a low loss micanol brown base.

The metal envelope of 6V6 is connected to pin 1 of the base, and was normally used as a ground. Pin 1 of the other members of the 6V6 family of tubes are usually not internally connected, although some may have the gray RF shield connected.

5871 – Ruggedized 6V6GT for operation under severe vibrations found in aircraft and similar applications. Radio Valve Co. of Canada Ltd., 1954 : RMA #859A.

5992 – Premium, ruggedized 6V6GT with heater current raised to 600mA. Bendix and GE known manufacturers.

7408 – 6V6GT with additional zero-bias characteristics.

6V6S – A modern production, large plated tube, heater current 500mA, with a reputation of handling high voltage and current ratings, from JJ Electronic.

6V6GT-STR – A modern production valve, heavy duty, handles higher plate current.

The Joint Army Navy (JAN) military specification tubes equivalents:

VT-107 – Metal 6V6.

6V6Y – Metal, with a low loss micanol brown base.

VT-107A – 6V6GT.

VT-107B – 6V6G.

British Ministry Of Supply valves for the Military & other governmental agencies have a CV number (CV = common valve). Supplied by Mullard & Brimar.

CV509 – 6V6G

CV510 – 6V6

CV511 – 6V6GT & 6V6GTY

CV1675 – 6V6 – General Post Office (GPO)

06OSW31, 316 OSW, HF3106, 6AY5 – All East German production 6V6GT's

In the Soviet Union a version of the 6V6GT was produced since the late 1940s which appears to be a close copy of the 1940s Sylvania-issue 6V6GT – initially under its American designation (in both Latin and Cyrillic lettering), but later, after USSR had adopted its own system of designations, the tube was being marked 6P6S (6П6С in Cyrillic.) Also 6П2.

5V6GT – Same as the 6V6GT, but with different heater ratings.

12V6GT – Same as the 6V6GT, but with different heater ratings.

VT227 = 7184 = CV510 – Cited equivalent, inadequate documentation, no RMA registration.

WT-210-00-82 – Cited equivalent, inadequate documentation, no RMA registration.

WTT-123 – Cited equivalent, inadequate documentation, no RMA registration.

Similar tubes

7C5 – 6.3V heater rating, clip-in Loctal B8G base, T-9 Bulb. Raytheon – 1939 RMA #162. Other version of this tube are 7C5-TV, 2C48, 2C50, N148, 6L31 CV885

14C5 – Same as 7C5 but with 12.6V Heater.

7C5LT – Small wafer Octalox base 8-pin T-9 Bulb. RCA – 1940 RMA #234.

6BW6 – British made miniature-tube equivalent of the 6V6, 9-pin base B9A.

6V6HD – NOT a 6V6, but relabeled weak Sovtek 6L6GC.

6AQ5 – Similar specifications to the 6V6GT, miniature glass envelope,7-pin base B7G. Other equivlants of this tube are the EL90, 6005, 6095, 6669, 6928, BPM 04, CK-6005, M8249, N7277C5

6P1P – 9-pin Soviet version of the 6AQ5.

6973 – US version, 9-pin base, higher plate voltage ratings, intended for high fidelity output applications.

6CM6 – 9 pin miniature equivalent type primarily intended for vertical deflection amplifiers in television receivers.

12AB5 – 9 pin miniature variant with a 12V heater, suitable for automotive radio applications.

References

Stokes, John. 70 Years of Radio Tubes and Valves. NY: Vestal Press, 1982.
Radio-Engineering magazine, December 1936, page 30, "New Products."
Radio Today magazine, December 1936, page 40, "New Tube Developments."
Radio Today magazine, January 1937, page 55, "New receiving tubes."
Radio News magazine, March 1937, page 567, "The Radio Workshop."
Radio-Craft magazine, October 1937, page 204, "New Tubes for the Radio Experimenter."
RMA (Radio Manufacturers Association) "Electron Tube Registration List"
Fender Musical Instruments, Amplifier Owners Manual's, 1983.
Jim Keeley Amplifiers, Amplifier Owners Manual.
Guitar Player Magazine, June 1983.
O'Connor, Kevin. T.U.T. Vol.5. Powerpress Publishing, 2004.
Receiving Tube Manual, RC-20. RCA corporation. 1964.

External links

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6V6