The eyeglass conundrum

I need eyeglasses to see close, which turns out to be a problem when I need to repair them. No matter how close I bring them to me, without the very items I am working on, I can't see. The solution to the eyeglass conundrum is simple. Get another pair of reading glasses for the repair work. Often when we are trying hard to focus in on a specific problem in our stereo systems, we just can't find the problem, no matter how close we look. Sometimes, it's because we're looking so closely at the usual suspects we fail to see the obvious—similar to being unable to see the forest because the trees are in the way. One of our customers recently detailed to me his struggle to solve a nagging hardness in the system. He tried everything: different cables, adding new power conditioning, toe out the speakers, room damping, different source, spikes under the equipment—all to no avail. I asked him what might have recently changed and it turns out he had upgraded his preamp. Hmmm. Seemed obvious to me, put the old one back in. Of course he'd thought of that already, but when he did that, all the benefits of the new preamp went away—benefits he was thrilled with. Had he tried replacing the amp? Well no, he said, that hadn't occurred to him. Of course you know where this story ends. The new preamp had done what it should, but in the process exposed weakness in the amp. Sometimes we look so closely at all the usual suspects that we miss the elephant in the room.