Audio Output

View as
Sort by

OSRAM BLACK BASE KT61 FROM NOV 1953

On offer today we have a beautiful Osram device. It tests as 100% emission as you can see from the attached test data label courtesy of our AVO VCM163. The envelope carries the etched ellipse cartouche and the black micanol base is tight to the envelope and shows clean uncorroded pins - a simply super device.
HK$451.21

25L6 KT32 NIB

HK$100.27

CLEAR TOP SCREEDED BOTTOM MULLARD WHITE PRINT ECC31 WARTIME MANUFACTURE

On offer today we have a superb ECC31, wartime manufacture showing superb white print and full emission and excellent matching from each section of this medium output power triode - superb in every way.
HK$671.81

EL37 MULLARD WHITE PRINT MATCHED PAIR

On offer today we have a lovely matched pair of Mullard EL37. Against the nominal AVO specification for 100% emission of :- Ia =100 mA; gm = 11.0mA/V @ Va = 250V; Vg = -15V Obtained results were:- y10: Ia = 72 mA; gm = 9.0 mA/V Y24: Ia = 70 mA; gm = 9.0 mA/V As you can see, these results are slightly lower than nominal but should give superlative performance in Push-Pull output applications as the matching of both gm and Ia is superb.
HK$1,102.97

GEC HAMMERSMITH 12E1, CV345, CV8025, 5B/351D GEC HAMMERSMITH BEAM TETRODE NEW BOXED

A very nice boxed device by the best manufacturer of these valves, dating from 1971.
HK$551.48

KT66 CV1075 OUTPUT BEAM TETRODE MATCHED PAIR FROM FEB 1967

Well, here's a tasty pair of device both clear glass "coke bottle' KT66 in GEC livery. The device carries markings in excellent white ink, a classic GEC/M-OV military cartouche with a date code of YB which equates to February 1967 and factory code Z which indicates Highgrove manufacture. The obverse sides carry perfect elliptical two tone blue and white GEC decals. The brown low loss micanol bases are both tight to the valve envelopes. This device has been tested using our AVO VCM163 against the specification for 100% emission of anode current, Ia =63 mA; mutual conductance gm = 6.3 mA/V @ At Va = 250V Vg = -15V. The results obtained were:- Ia1 = 90 mA. gm1 = 6.0 mA/V. Ia2 = 93 mA. gm2 = 6.1 mA/V. These test figures indicate not only a very strong pair of devices which EXCEED nominal specifications but also are a supremely matched pair - not to be missed.
HK$2,857.69

MATCHED PAIR OF MULLARD EL33 OLD SHIELD WHITE LABEL

On offer today we have a beautiful matched pair of Mullard manufactured devices. Both test as 100% emission as you can see from the attached test data label courtesy of our AVO VCM163and match very closely for both anode current Ia and mutual conductance gm.
HK$752.02

MULLARD EL37 PENTODE BROWN BASE WHITE PRINT

Wowee, a lovely EL37 here today for you to try n buy. Rarely offered oft desired but here to sell today Against the nominal AVO specification for 100% emission of :- Ia =100 mA; gm = 11.0mA/V @ Va = 250V; Vg = -15V Obtained results were:- Device 1: Ia = 99 mA; gm = 10.5 mA/V As you can see, these results are slightly lower than nominal but should give superlative performance in Push-Pull output applications.
HK$1,102.97

MULLARD WHITE PRINT ECC31 WARTIME MANUFACTURE

On offer today we have a superb ECC31, wartime manufacture showing superb white print and full emission and excellent matching from each section of this medium output power triode - superb in every way.
HK$752.02

MULLARD WHITE PRINT ECC31 WARTIME MANUFACTURE

On offer today we have a superb ECC31, wartime manufacture showing superb white print and full emission and excellent matching from each section of this medium output power triode - superb in every way.
HK$752.02

OSRAM BROWN BASE KT61 FROM FEB 1957

On offer today we have a beautiful Osram device. It tests as 100% emission as you can see from the attached test data label courtesy of our AVO VCM163. The envelope carries the etched ellipse cartouche and the brown micanol base is tight to the envelope and shows clean uncorroded pins - a simply super device.
HK$451.21

OSRAM BROWN BASE KT61 FROM FEB 1958

On offer today we have a beautiful Osram device. It tests as 100% emission as you can see from the attached test data label courtesy of our AVO VCM163. The envelope carries the etched ellipse cartouche and the brown micanol base is tight to the envelope and shows clean uncorroded pins - a simply super device.
HK$451.21

OSRAM FAT BOY KT66 VT75 WARTIME ISSUE GREY GLASS

The British Marconi-Osram GEC Valve Company of England introduced in 1938 the legendary KT66, K.T standing for kinkless tetrode. This designation was given as when the performance of the valve is measured from it's output curve it was found to be linear - hence it's great sound. The KT66s superlative sonic performance found audio fame in the Q.U.A.D II amplifier in the field of hi-fi and in 1965 Jim Marshall used the KT66 in the JTM 45 guitar amp to power those famous biting solo's to a crescendo in Eric Clapton's band!! Hence the KT66 joined the rock and roll valve legend in the first position where it has been ever since. The performance of the MOV originals is all due to the heavy grade glass and rigid mica spacers with stiff grid support specified by MOV engineers to eliminate microphonics and provide longevity of performance. Many replicas of this valve have been made over the years, mainly in China but these replicas don't 'cut the mustard' in comparison to the original GEC MOV devices in terms of sound, longevity and visual aesthetics. The problem is not just locating vintage devices but getting good ones which have been fully tested using an AVO VCM to determine stability, microphonics, cathode heater insulation hot & cold, internal shorts, anode current and mutual conductance. For this you need expertise and the requisite Valve Characteristic Meter - hard to find and jealously coveted these days - and so they should be as they cost the price of an average semi back in the 1950's The device offered here today is AVO VCM163 tested and as good as you can get. Its a GREY glass, black low loss micanol based unit from wartime production. The base is tight to the envelope with no sign of re-fixing. The markings on the front are in etched cartouche and show KT66 Osram and the rear of the envelope carries a perfect Osram ellipsoid yellow and blue decal. Tested using an Avo specification for 100% emission of anode current, Ia =63 mA; mutual conductance gm = 6.3 mA/V @ At Va = 250V Vg = -15V the results obtained were:- Ia = 95 mA. gm = 8.0 mA/V.
HK$1,955.26

6L6 5881 CV1948 VT107 BEAM TETRODE VARIOUS MANUFACTURERS.

Beam tetrode output valve
From HK$140.38

6V6G CV509 VT-107A BEAM POWER TETRODE VALVE VARIOUS MANUFACTURERS

Octal beam power tetrode valve
From HK$220.59

6V6GT CV511 BEAM POWER TETRODE VALVE VARIOUS MANUFACTURERS

Octal beam power tetrode valve
From HK$188.01

KT61 6P25 EL33 CV1438 CV2938 N147 OM9 AUDIO BEAM TETRODE

beam tetrode octal based valve
From HK$350.94

KT66 CV321 CV1075 VT75(RAF) OUTPUT BEAM TETRODE VARIOUS MANUFACTURERS

Kinkless beam tetrode output valve
From HK$1,102.97

KT88 CV5220 6550 OUTPUT BEAM TETRODE VARIOUS MANUFACTURERS

Kinkless beam tetrode output valve
From HK$802.16