For years I've been carrying around a bunch of minidisc recordings that I'd like to preserve by getting them onto my Mac laptop.  My portable MD recorder has only an optical digital out.  Has anybody seen a super cheap interface that takes an optical input?  Are there some older models I should...

Does anyone offer an opamp buffer PCB? I've looked around for awhile, and I'm surprised I can't find one. I need to drive a DSP with a low input impedance (6K) with the output of either a tube or passive preamp. This DSP will only operate below 200hz, so I do not need incredible resolution...