GZ34 Mullard; f31 Fat base, 1959 NIB v27

Description

Here is a Mullard Miniwatt GZ34 tube; early 1959 production, produced in the Mullard factory in Blackburn, UK. This is the famous  Fat Base GZ34 version. According to many even better than the already outstanding Blackburn/Philips versions. The tube has zero dents plates and an f31 etch code. The tube is supplied in an original factory box.

The GZ34 is a full wave rectifier. The Philips 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. 

These Philips made GZ34 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) = 10,5 Volts.

Test results*

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

GZ34 V19

Ia (anode current): Gas test, Shorts test:

122 / 127 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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