Cleaning up my equipment. Due to a malfunction in the original preamp of my YAMAHA APX, I've installed a TransAcoustic system preamp. It delivers a more powerful and louder sound than a YAMAHA TransAcoustic guitar. Mini-concerts are possible in a small room without a guitar amp. Neck, nut, and saddle adjustments have been made. After fret leveling for optimal condition, I installed a DOUBLE OS1. This will change your perception of acoustic guitars. ⭕️ Search YouTube for DOUBLE S1 OS1 【Preamp】 ⭕️ TransAcoustic Function: The condenser microphone and piezo pickup capture the vibrations of the guitar and strings, and the preamp applies effects. The signal is then sent to an actuator (vibrator) installed on the back of the guitar, which resonates the body. The natural sound and the sound with effects are mixed and emitted from the guitar. You can enjoy the effect sound from the soundhole without any connections. You can also connect to a guitar amp via line out and play it as a regular electric-acoustic guitar. ⭕️ Effects: Microphone blend, delay, chorus, and reverb can all be applied simultaneously. ⭕️ AUX: A unique feature not found in other preamps. It can connect via Bluetooth, allowing you to import audio from an iPhone, etc., and play along with it. ※ You can also enjoy music as a Bluetooth speaker by hanging the guitar on the wall. ⭕️ Power is supplied by a rechargeable battery, charged via a USB-C cable. 【Features】 ◯ APX series solid top. ◯ Good response with clear and well-defined sound quality. 【Condition】 ◯ Fret leveling, neck, nut, and saddle adjustments result in a low action of approximately 2.6mm at the 12th fret, 6th string. ◯ Truss rod has room to spare in both directions. ◯ Frets show no wear and are polished to a shine with steel wool. ◯ Two monitor holes have been added to the side, delivering sound directly to the player. ◯ The APX's characteristic oval rosette is also in beautiful condition. 【Specifications】 ◯ Color: Dark Green Sunburst ◯ Top: Solid Spruce ◯ Sides & Back: Nato ◯ Neck: Nato ◯ Fingerboard: Rosewood ◯ Bridge: Indian Rosewood ◯ Nut Width: 42mm ◯ Scale: 650mm ◯ Body Thickness: 80mm - 90mm ◯ Tuners: Silver chromatic. Shiny and without any dullness. ◯ Accessories: Preamp manual and charging cable