Description
Here is a pair of Mullard GZ34 tubes; old production, produced in the Blackburn factory in the UK. The Mullard GZ34 is a full wave rectifier. These tubes bear the brand name Philips. The tubes have a halo-getter and both have 7 notches in their plates. The tubes are produced in 1964 and 1969 respectively. The Mullard GZ34 is famous for its contribution to the tonal quality of tube amplifiers and their extreme long life.These Mullard made tubes deliver superior performance compared to the Chinese and Russian new production. They are highly regarded also for application in guitar amplifiers. The tubes are supplied in white tube boxes.
Both tube no show any signs of use and therefore are considered to be NOS.
Please note that both tubes are of the 7 notches series but still one has a red rim and the other not.
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 fulfil the factory requirements for a new tube. In addition there is a excellent emisson balance within and between both tubes!
| GZ34
V24 |
Ia (anode current):
Gas test, Shorts test:
|
133 / 136 mA
OK
|
< NOS
|
| GZ34 2
V25 |
Ia (anode current):
Gas test, Shorts test:
|
136 / 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.
Please read our test notes and shipping policy before buying !
Short description
| Tube type | GZ34 |
| Quantity of Tubes | One pair |
| Brand | Philips / Mullard |
| Manufactured in | Blackburn, UK |
| Date codes | f32 B4G3 & f33 B9D1 |
| Construction | Grey plates with 7 dents and black base |
| Getter Construction | Halo-getter |
| Print Condition | Pristine, See pictures |
| Box included | Generic white box |
| Equivalent tubes: | 5AR4 |
| General test results | < NOS |
