You have a REF 3 pre-amp and a 110 amp. All from Audio Research. I would investigate a used Ph6, Ph8, REF 2SE or 2 phono stage. They would match very well with your existing gear and sound great. The turntable, arm and cartridge on the other hand. Well, that's a different story. Hard choices and totally dependent on what your budget is. But remember, there are a lot of very nice used turntable/arm combinations out there.
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