Vacuum Tube CZ-501-V for 2A3/300B Voltage Amplification, Japanese-made WE310A, New and Unused

Vacuum Tube CZ-501-V for 2A3/300B Voltage Amplification, WE310A Equivalent, New Unused
Heater Specifications: 6.3V / 1.0A

The CZ-501-V is a voltage amplifying pentode tube originally manufactured by NEC (Nippon Electric Company) and others for communication purposes.
It was specially designed as a vacuum tube for communication and broadcasting equipment used by the former NTT (Nippon Telegraph and Telephone Public Corporation) and NHK (Japan Broadcasting Corporation), and has unique specifications different from those for general radio use. Among audio enthusiasts, it is known as a Japanese-made WE310A equivalent, possessing performance comparable to the renowned American tube, the WE310A.
Key Features and Specifications
Application: Voltage amplification (primarily for LF amplifiers in wired communication and broadcasting equipment).
Heater Specifications: 6.3V / 1.0A.
*Please note the similarity to the CZ-501-D, which has a 3.5V specification, and be careful not to confuse them.

Typical Operating Example (at Vp=250V):
2nd Grid Voltage (Vsg): 130V
Bias (Vg): -2.5V
Plate Current (Ip): 7.0mA
Transconductance (gm): 3.5mS

Use in Audio
After its role in communication ended, it gained popularity as a first-stage tube for DIY amplifiers, as introduced in books such as Isamu Asano's Fascinating Vacuum Tube Amplifiers. It is particularly regarded as a good match for driving directly heated triodes (such as 2A3 and 300B).
As it was not commercially available to the general public, most units currently in circulation are surplus or used items from that era. Compared to the CZ-501-D, the CZ-501-V tends to be seen less frequently in the market.

Please check the multiple images for current scratches and dirt. Those who are extremely sensitive to such details should refrain from purchasing.

● As this is a product from several decades ago, quality cannot be guaranteed.
2026_04_10