I have a Marthas Dad SUT. These are made by Larkrise with Partridge transformers (6x) and are silver wired and have silver RCA connectors. This is one of the last that were made and has slightly different internal wire to the earlier models. Works perfectly with medium (0.5mv) output cartridges and a little lower. Partridge reputedly made the best tranformers, period. Marthas dad has decided to hang up his soldering iron, so the only way to get one of these now is to buy "2nd hand". I have changed cartridges and needed a 10x SUT which was the very last one made by Marthas Dad. The unit I am selling has had little use, so £225 + pp.