EL34 Philips Xf1 / Laboratory samples D-D getter 1957 v30 v36

765,00

Highlights

    • Philips laboratory samples !!
    • Best sonics
    • Philips Sittard production
    • Xf1 X7F 1957 same date code  !!
    • Matched pair
    • Double D getter

1 in stock

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Description

Here is a pair of Philips Miniwatt EL34 early production tubes. The pair is a selected for the Philips Physical laboratory NAT LAB; which used the highest grade tubes only;  see pictures and test data.

The Philips Sittard production Double D-getter is, apart from the metal base EL34, considered as the absolutely best sounding EL34 ever. 

The pair has excellent specs. Both tubes have date code Xf1 X7F

The measurement data below show that the pair is matched. And fully in line with the Philips specification for an EL34.

Test results*

The measurement data below show that both tubes are matched. 

Valve 1

V30

Ia (plate current):

Transconductance (Gm):

Gas test, Shorts test:

96 mA          

11,9  mA/V

OK 

=  NOS

= NOS

 

Valve 2

V36

 Ia (plate current):

Transconductance (Gm):

Gas test, Shorts test:

102 mA      

12,2  mA/V

OK

= NOS

= NOS

 

Telefunken measuring values for new unused tubes:

  • The rated emission value for a new EL34 is:  100 mA. 
  • The rated transconductance value for a new EL34 is:  11 mA/V . 

For Telefunken specs info see last picture 

Test condition & 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) = 265 Volts, Ug = -13,5 Volts and Uf = 6,3 V ± 3% (factory conditions). Please read our test page.

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 !

 

Summarized description

Tube type EL34
Quantity of Tubes One pair
Brand Philips Miniwatt
Manufactured in Sittard, Netherlands
Date code 2 x   Xf1 X7F June 1957
Plate Construction welded grey plate
Getter Construction double D getter (see pictures)
Print Condition excellent; see pictures
Box included Generic white boxes
Equivalent tubes:   6CA7
General test results  NOS