All rights of photos and text reserved. Usage of photos or text from my blog on other websites or for any other purpose only with prior permission. If you want to use any material from my blog please contact me by email.

Wednesday, October 27, 2021

Tube of the Month : The 5Z3


After the recent introduction of the ELROG ER5Z3, I thought it is a good idea to pick the 5Z3 as tube of the month.

The 5Z3 is a directly heated full wave rectifier. It is electrically identical to the 5U4 but has a different base.

While the 5U4 comes with a 8 pin Octal base (of which 4 pins are not used) the 5Z3 is the same tube on a 4 pin UX4 base. The pinout is shown on the left. Both tubes have a 5V filament which consumes 3A. They have the same maximum ratings and characteristics. See the RCA data sheet for all technical details. The 5Z3 is a member of a small family of 3 tubes which share the same electrical characteristics and only differ in the base. The third one is the 5X4 which has the same base as the 5U4 but a different pinout. While the 5U4 has seen a widespread use and still is used a lot in current production amplifiers, the 5Z3 and 5X4 were less popular and are rarely used nowadays. Let's have a look at some 5Z3 rectifiers from different manufacturers, starting with RCA:

Another RCA 5Z3 made for the military:

The military designation of the 5Z3 is VT-145

Next we have a National Union 5Z3:


And lastly the ELROG ER5Z3, the only current production 5Z3 I am aware of:

Best regards


1 comment: