Best KT66 listed atEL84

KT66 GEC / Genalex / Osram England (click on links below to check stock) KT66 coated glass 1950's KT66 clear glass 1950's KT66 clear glass 1960 - 1970's TO BUY CV1075=KT66
(The KT66 GEC has a very refined smooth midrange presentation, detailed and rich harmonic texture) (It is a very good alternative to 6L6GC)
KT66 GEC UK and Genalex UK brown base "Gray Coated Glass" 1950's (smooth rich textured sound, the oldest and best sounding KT66 ever made) - Decware Torii MK IV - Metro Amp (George Metropoulos) - Marshall JTM 45 - Carr Mercury - Dr. Z Route 66 - QUAD II - Victoria Regal 2 - Emery - Leak 12.1 mono amps TO BUY KT66
CV1075=KT66 MO-Valve (GEC), Hammersmith England (Z date code around 1956) coated glass same date codes in white boxes, best in stock TO BUY CV1075=KT66

KT66 Osram / Genalex "Black Base and Gray Coated Glass" mid-1950's TO BUY KT66 OSRAM BLACK BASE 1950's

KT66 GEC England "Clear Glass" late 1950's (cup-shape getter halo) ("cup-shape" getter halo, smooth rich textured sound, the oldest and 2nd best sounding KT66 ever made) (oldest and rarest clear glass version of KT66) - ASL Leyla 2002 power amp - Marshall Bluesbreaker reissue 1964 - Dr. Z Route 66 - JTM45 - Pure Sixty-Four The "64" Head - Quad II - THD Bivalve - Leak 12.1 mono amps TO BUY KT66 GEC Clear Glass

KT66 GEC and Genalex "Clear Glass" 1960 - 1983 (smooth, rich, creamy, lush, all describe the sound of these KT66) (comments: "the KT66 arrived ! They are simply FANTASTIC, I find them better than my RCA 6L6GC") - Marshall Bluesbreaker JTM45 MKIV (tremolo) from 66 - Marshall Bluesbreaker reissue 1964 - Marshall JTM45 - Marshall JTM45/100 - ASL Leyla 2002 power amp - Dr. Z Route 66 - Metropolis JTM-45 2009 - Pure Sixty-Four The "64" Head - Quad II - THD Bivalve - Soultone 1986ps TO BUY KT66 GEC Clear Glass
SONIC COMMENTS: -------------- "Brendan, Chris Schaefer here again with the news that the KT66's you sold me are now working beautifully in a 40w 1x 12" combo amp that really smoothly shimmers. Almost inexplicable. ZOW! I will keep you abreast of where to see and hear this amp (I call it the "1961") on the web within the next couple months. Happy Holidays! Chris Schaefer"
KT66 EQUIVALENT = KT8C GEC (England) It is a beam power tube almost identical to the KT66 (made by the same company) EXCEPT that is has a 5 pin british type ceramic base and a top cap anode connection. SPECS: (similar to KT66 specs) Heater Voltage: 6.3V Heater Current: 1.3A Anode Voltage: 600V max Screen Voltage: 300V max Anode Dissipation: 25 Watts max Screen Dissipation: 3.5 Watts max Mutual Conductance: 6 ma/volt (measured at Plate V= 250, Vg2 (screen)= 250, Ia= 70ma) CV1079=KT8C listed below CV1079=KT8C GEC UK NOS 1961(KT-66) equivalent TO BUY KT8 and KT8C
TO BUY KT8 black base NOS
5-Pin Sockets for KT8C: ----------------------- Special quality black high temperature material. Current UK production. New improved design with phosphor bronze contacts which can withstand higher voltages. TO BUY KT8C sockets The KT8C tube is good for DIYers. HISTORY: ------- The KT8 was a not very successful British attempt to emulate the American type 807. The 807 was based on the RCA type 6L6 beam tetrode, which had a long, fairly thin, anode and a carefully-aligned grid structure. The 6L6 employed rapidly-accelerated electrons and short electron paths. This made it efficient but its characteristic had a distinct residual kink. It was a very successful valve but its characteristic was not quite straight enough to give the ultimate in audio quality at high output levels. The KT66 was essentially a 6L6G redesigned with a larger cathode and a shorter, fatter anode. The KT66 had less rapid acceleration, longer electron paths, and almost no kink. It was ace for audio hi-fi but the electrons took longer to reach the anode and were more open to influence from magnetic, etc, fields on the way. Moreover, under HF conditions the electron stream was not perfectly in phase with the grid signal and this resulted in a loss of output power. The KT8C was based on the KT66 but the longer electron path (compared to the 6L6 and 807 types) was a disadvantage at the high radio frequencies. Not a problem at AF but the KT8 was pretty useless above 15 MHz whereas the 807 was still doing great things at 60 MHz. In the end the British Services abandoned the KT8C in favour of the American 807. Attempts to make 807s in the UK were largely unsuccessful. The anode is made of plates, shaped to increase surface area and blackened to radiate more heat. The base is ceramic indicating high temperature operation and the need for good insulation.