This is a heavily modified version of the LXV-OT7 (not MK-II) vacuum tube hybrid pre-main amplifier, a supplement to the monthly Stereo magazine. The modifications include replacing capacitors on the circuit board, vibration damping, and shielding. It's housed in a genuine wood case (spruce) with multiple layers of varnish. This amplifier, a collaboration with LUXMAN in the Stereo magazine supplement series, is characterized by its use of a 12AU7 vacuum tube to shape the sound. While the MK-II version came later, I personally prefer this one for its characteristic vacuum tube sound. Even when assembled as is, it's a device with excellent cost performance, but by replacing components and applying vibration damping and shielding, I believe it has reached a level that makes you think, "Can a supplement series item really go this far?!" It has been a core piece of equipment in my home sub-system, and I have grown fond of it. However, I am selling it because I have been using it less due to the use of other self-made amplifiers. This item has been modified with the following ① to ③: ① Electrolytic capacitors on the circuit board have been replaced with high-capacity, audio-grade components. ② Coupling capacitors have been replaced with 1μF film capacitors. Please refer to the attached circuit diagram and photos before and after the replacement for details. There are many examples of LXV-OT7 capacitor replacements, but I used my own carefully selected components, arrived at after trial and error in replacement and listening tests. ③ Copper tape was applied to the top panel of the main unit for noise shielding and vibration damping. ④ The wood case is a separately sold genuine spruce product, which has been coated with multiple layers of water-based varnish. The original OT7 is characterized by its delicate expressiveness and the rich tonal quality provided by the vacuum tube, but it also showed a nervous and dry side. With these modifications, the core of the sound has become thicker, while also adding richness and the beauty of reverberation, shifting the overall tone to a warm color. It's not so much suited to any particular genre like jazz, rock, classical, or vocals, but rather has a unique sound in all genres. I think the real pleasure is swapping out vacuum tubes, so I have deliberately returned it to the original tubes. Mullard reissues were the best for me. Using an analog (transformer) power supply will further improve the sound quality, so I recommend it. Model Name: LXV-OT7 Manufacturer: LUXMAN Accessories: Dedicated spruce wood case (hand-painted), genuine AC adapter