GZ34 pair; Philips Miniwatt Sittard,Double D f31 version!, 1958, NOS specs v20/v37

Description

Here is a pair of Philips GZ34 tubes; very early production, produced in februari and november 1958 in the Sittard factory in Netherlands. This is the famous early f31 GZ34 version. According to many even better than the later outstanding Philips / Mullard rectifiers. The tubes have a DD-getter and an f31 etch code. 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. The tubes are supplied in Philips boxes.

These Philips 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) = 10,5 Volts.

Test results*

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

Both tubes are balanced; within en between! 

GZ34 V20	Ia (anode current): Gas test, Shorts test:	122 / 115 mA       OK	>  NOS
GZ34 2 V37	Ia (anode current): Gas test, Shorts test:	110 / 111 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