Description
Here is a pair of GZ34 tubes; produced Januari and Februari 1959 in the Philips factory in Sittard the Netherlands. These tubes bear the brand name ADZAM. The tubes have a DD-getter and an f31 etch code. 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 white tube boxes. Both tubes show no signs of use (except 2 scratches on the base of V3) and are considered NOS.
These Philips & 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
V29 |
Ia (anode current):
Gas test, Shorts test:
|
124 / 122 mA
OK
|
NOS
|
GZ34 2
V32 |
Ia (anode current):
Gas test, Shorts test:
|
118 / 122 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.
Please read our test notes and shipping policy before buying !
Short description
Tube type | GZ34 |
Quantity of Tubes | One pair |
Brand | ADZAM / Philips |
Manufactured in | Sittard, Holland |
Date codes | f31 B 9B & f31 B 9A (1959 & 1959) |
Construction | Grey plates with 0 dents and black base |
Getter Construction | DD-getter |
Print Condition | See pictures |
Box included | Original factory box |
Equivalent tubes: | 5AR4 |
General test results | NOS |