Opera Audio KT88 Push-Pull Amplifier, Consonance M99 Plus. I've researched it, but it's a somewhat mysterious brand. It has a history dating back to 1994 and seems to handle a wide range of audio equipment, not just vacuum tubes. The reason I chose this KT88 push-pull amplifier was because of its stylish wooden frame and very simple circuit design. However, it's not like they cut corners; it uses WIMA capacitors, and relays activate during output switching, showing attention to detail. The component placement is characteristic of circuit board wiring, with key areas well-considered. The first stage uses a 12AX7, and the driver stage uses a 6SL7 (6H9C). While a 6SN7 might seem better in terms of circuit design, I've adhered to the original design at the time of purchase. The output stage is a KT88 push-pull configuration. I used PSVANE KT88C tubes. The output is approximately 15W at 8Ω. It's enough to annoy the neighbors if you turn the volume up too high. There's almost no hum noise when silent, but a slight noise is audible when the volume is increased. Please check the video I filmed to confirm. Also, one of the speaker output terminals has been replaced. The power cable is not included. It will be provided for an additional 500 yen for those who want it. https://youtu.be/Jlmyn6bvLjA?si=mtsdCjQ3h2PttDfJ Please judge the scratches, dirt, and appearance from the photos and video. As this is a personal sale, please refrain from after-sales support or detailed questions. Discrepancies are likely regarding subjective matters such as noise when silent and appearance. Please be sure to check the description, video, and images, and agree to the terms. In principle, no claims, no returns, and no cancellations are accepted. Please refrain from purchasing if you are a perfectionist or expect the same condition as a new product from the manufacturer. Please purchase only if you understand that this is a used, manufactured, and vintage item.