Quad EL34, Telefunken Quad (Mullard; Xf2) ANOS V334 335 336 336

825,00

Highlights

    • NOS looks & excellents test values
    • Telefunken selection
    • Mullard Blackburn !
    • Best sonics

1 in stock

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Description

Rare Quad Telefunken EL34 tubes produced by Mullard in Blackburn, Uk.

Detailed description

These Telefunken EL34 with single halo getter and welded plate are a 1961 production of Mullard Blackburn. All four tubes have  NOS specs. One pair of tubes has date code Xf2 B 1A1 (1961 first week of januari) the other pair is produced in the same year in februari (date code Xf2 B 1B2). The quad has NOS test values and excellent looks. 

Note: my tubes are often not the cheapest. But it is very hard to find better tubes !

Sonics

The Mullard Xf2 EL34 is considered by many as an outstanding sounding EL34 tube; a lot better than todays production! I refer to the many reviews on internet.

Test results

The measurement data below show that the tubes are platinum matched. 

Valve 

V334

Ia (plate current):

Transconductance (Gm):

Gas test, Shorts test:

 95  mA

11,8  mA/V

OK

> NOS

> NOS

 

Valve 

V335

Ia (plate current):

Transconductance (Gm):

Gas test, Shorts test:

 95  mA

11,9  mA/V

OK

> NOS

> NOS

 

Valve 

V336

Ia (plate current):

Transconductance (Gm):

Gas test, Shorts test:

 93  mA

11,6  mA/V

OK

>  NOS 

> NOS

 

Valve 

V337

 

Ia (plate current):

Transconductance (Gm):

Gas test, Shorts test:

86  mA

11,0  mA/V

OK

> NOS

> NOS

 

Factory Specification for new unused tubes (Telefunken/Philips/etc.)

  • The rated emission value for a new EL34 is:  75 mA.
  • The rated transconductance value for a new EL34 is:  11 mA/V. 

As specified in AVO Valve Data Manual 23rd edition 1981. 

Test conditions & equipment:

Mutual transconductance, plate current, gas and shorts test equipment: AVO Mk IV (Dutch army tester) , AVO Valve Data Manual 23rd edition 1981, RFT stabilised mains, Utracer3+, Philips PE 4832, 2x Korad KA3005P programmable power supply, 2x Keithley 2700 and 2x Fluke 145. Test conditions: Ua (plate voltage) = 250 Volts, Us (screen voltage) = 250 Volts, Ug = -13,5 Volts and Uf = 6,3 V ± 3% (Mullard conditions). Please read our test page.

NoteLook for a detailed description of testing methods on the site: tubes4hifiaudio.ctpu.nl/tube-testing-quality-control/

Summarized description

Tube type EL34
Quantity of Tubes One quad
Brand Telefunken
Manufactured by Mullard Blackburn, UK
Date code 1961  code: Xf2 B 1A1 & Xf2 B 1B2
Plate Construction Welded grey plate
Getter Construction Halo getter
Print Condition Excellent; see pictures
Box included Generic white box
Equivalent tubes:  6CA7
General test results  NOS
Please study photos carefully; what you see is what you get! Ask any questions before bidding. Thanks

Please read our test and shipping policy before buying !

Quad example