This is a 6L6GC vacuum tube amplifier using a Sanei Musen chassis. The first stage is a 12AU7 (no brand). It has a two-stage SRPP drive configuration. The output stage uses 6L6GC (5881) tubes made by Sovtek. It is used in triode connection. It also employs a constant current self-bias using LM317T, which is a key feature of the circuit, ensuring a constant bias current. Both vacuum tubes are unused. Most of the internal parts, such as resistors and capacitors, are also unused and are still in the process of aging. The transformer is a TANGO ST-130. The output transformer and choke coil are of unknown manufacturer. These are used items. It is in very good condition and is recommended for beginners of vacuum tube amplifiers. Please consider the included video as well. https://youtu.be/8DGKWtpE9I0?si=jpNA1aZ13uyZBLo0 As this is a private sale, please refrain from after-sales support or detailed inquiries. Subjective matters such as noise when silent and scratches or dirt on the exterior are prone to discrepancies. Please be sure to check the description, video, and images, and make your purchase with your understanding. In principle, no claims, no returns, and no cancellations are accepted. Please refrain from purchasing if you are sensitive or expect the same condition as a new product from the manufacturer. Please purchase only if you understand that this is a used, handmade, and vintage item.