We have secured a supply of vacuum tubes, so we are resuming the limited-time special price of 9,000 yen. ● This is a booster that uses vacuum tubes. It adds the characteristic sound pressure of vacuum tubes and a slight boost to the original sound. In this listing, we will provide it with a used 12AT7 tube installed. 12AU7, 12AT7, 12AV7, and 12AX7 tubes can be used, so please try different tubes you have to find your favorite sound. We recommend a 12V center-negative adapter for more stable operation, as it has a built-in regulator. ● Although it's a booster, it's set to be almost a buffer at the 12 o'clock position to prevent distortion even when clean. ● Because it uses vacuum tubes, there will be some hum noise compared to a transistor natural booster. This is not a defect. ● When placed after a tube screamer, you can enjoy the nuances of a vacuum tube even with a transistor amplifier. ● Recommended for those who feel the sound is thin with line input. Currently, it is used in recordings by several studio musicians. ● Hand-wired on a universal board. ● 9V battery cannot be used. ● Please use a 9V center-negative power supply, which is commonly used for effects pedals. (12V is more stable) ● Aluminum case size: 60 x 112 x 31 (height) mm ● True bypass specification ● EBK is a name used only for online sales. In our main business, we adjust, manufacture, and repair amplifiers, effects pedals, and other equipment, specializing in blues-related gear, and also adjust guitars. ● Six-month warranty: We manage customer records, so if a failure occurs under normal use, we will compare it with the shipping records and repair it free of charge within six months. (Shipping costs will be the responsibility of the customer.) ● Shipping included. Please refrain from price negotiations.