I purchased an AP757 kit, a 6550/KT88 triode-connected push-pull amplifier from Audio Senka, over a decade ago. However, I gave up on assembling it because the circuit was complex and seemed to require bias adjustment. A few years later, I used only the chassis, transformers, and block capacitors from the kit, and assembled a 6G-B8 triode-connected push-pull amplifier with a self-bias circuit using other parts I had on hand. I had it listed separately, but it has already been sold. I am offering the unused parts from the kit to someone who can make use of them. This is a set of two 6189W tubes, in a white box. They appear to be made by Philips in the USA, and I believe they are of good quality, having been selected by Audio Senka. The 6189W is a high-reliability tube equivalent to the 12AU7. I have confirmed the continuity of the heaters. As a reference, I will also include a copy of the kit's circuit diagram as a bonus. The unused original front-end vacuum tubes, resistors, capacitors, diodes, and mechanical parts are listed separately. Although they are unused, a long time has passed, and please understand that returns are not possible even if there are problems with the product upon arrival.