Telefunken Black Diamond GZ34 / 5AR4
The TELEFUNKEN GZ34-TK is an excellent replacement for any amplifier using GZ34 or 5AR4 rectifier tubes.
The GZ34 isn't a very talked about tube, but it is one of the most common rectifier tubes found in audio, especially in guitar amps. Rectifier tubes were some of the very first tubes to be invented since their purpose is one of the first requirements in electronic and audio design.
A rectifier is an electronic device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The rectifier is indeed an essential block that helps create the sound of an amplifier.
I originally wanted this tube for my Princeton Reverb, but it sounded better in my Fender 1975 Silverface Deluxe Reverb, especially when I played both amps together. Not so much by itself, especially when compared to the louder RCA, but it had a balanced tone to all the tubes within, bringing out a nice warm deep low on the Deluxe. Just had to turn up the volume a little more, but this tube definitely has a place in the line up.
reviewed by: Joe Morris