GZ34 pair; ADZAM, Mullard production, red rim version!, NIB V2/3

Description

Here is a pair of Mullard GZ34 tubes; old production, produced in the Blackburn factory in the UK. These tubes bear the brand name ADZAM. The tubes have a halo-getter and an f32 etch code. The Mullard GZ34 is famous for its contribution to the tonal quality of tube amplifiers and their extreme long life. They are highly regarded also for application in guitar amplifiers. The tubes are supplied in white tube boxes. Both tubes show no signs of use (except 2 scratches on the base of V3) and are considered NOS.

These Mullard made tubes deliver superior performance compared to the Chinese and Russian new production.   

Test method

Anode current, gas and shorts tested with: AVO CT-160 (Dutch army tester), Utracer3+, AVO Valve Data Manual 23rd edition 1981, Philips 1532, RFT stabilised power supply and 2x Keithley 2700. Test condition: Ua (plate voltage) = 10 Volts.

Test results*

The measurement data below show that the GZ34 tubes are in excellent condition and easily fulfil the factory requirements for a new tube. 

GZ34 V2	Ia (anode current): Gas test, Shorts test:	168 / 159 mA       OK	<  NOS
GZ34 2 V3	Ia (anode current): Gas test, Shorts test:	139 / 132 mA       OK	<  NOS

*The emission value for a new GZ34 valve at the used test conditions is: 120 Milliamperes (mA).  (Factory data sheet)

 

* Specified measurement data

Test results on other testing devices may supply different values. Just in case of mismatch of “standard” values of the different tube testers “standards”. My test results refer to tube data sheets provided by the original tube producers. (You’ll find them easily on the web.) And are obtained with the specified test equipment.

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Short description