Power socket: DC3.5/5.5*21 Tube: 6J3 (The tube is disassembled) Power supply: DC1216V, current 1A or more (DC12V 1.5A supply power is recommended) Product support tube: 6J1 6J2 6J3 6J4 6J5 6A2 6K4 6K5 6AK5 6AU6 6BA6 6BD6 EF93 6K7 GE5654 etc. Key benefits Flexible tube compatibility: supports a wide range of common miniature tubes, enabling tone experimentation and easier replacement. Simple, reliable power: operates from a standard DC supply in the 12 to 16V range with 1A or more current, with a recommended 12V 1.5A for performance. Replaceable tubes: swap among multiple tube types to tailor response and characteristics without changing the chassis. Compact, straightforward usage: designed for easy setup in DIY projects, restorations, or test/debug workflows. Specifications at a glance Power input: DC1216V, 1A minimum (1.5A recommended for performance) Power socket: DC3.5/5.5*21 Tube format: 6J3 (the tube is disassembled) Tube compatibility for replacement: 6J1, 6J2, 6J3, 6J4, 6J5, 6A2, 6K4, 6K5, 6AK5, 6AU6, 6BA6, 6BD6, EF93, 6K7, GE5654, etc. Tube compatibility (typical replacement options) 6J1 6J2 6J3 6J4 6J5 6A2 6K4 6K5 6AK5 6AU6 6BA6 6BD6 EF93 6K7 GE5654 etc. Use scenarios DIY audio project: use as a compact preamp or signal stage in a custom build. Swap tubes to explore different tonal responses and dynamics using the supported tube types. Vintage radio or amplifier restoration: or test tubes quickly with the compatible replacement list to evaluate performance and compatibility. Electronics hobbyist education: a practical platform to learn about tube substitution, power requirements, and tube socket handling with real parts. Notes The included tube is 6J3 and is presented disassembled; handle with care during installation and replacement. Ensure your DC power supply provides stable 1216V within the 1A range for reliable operation.