I think Dave is right. The only thing to watch out for is that there some very early versions of the F1-X floating around where the deep switch can drop the gain, as it's more of high cut than a low boost. Once they got into the swing of production, they compensated for that. I had an early one and Ron sent me the mod to fix that, but I never bothered.
Of course, after a certain amount of time, all electrolytics need to be replaced, but you'll notice some hum when the filter caps start to go bad. Think of it like having to change your strings every 25 years or so. In the grand scheme of things, it's a trivial repair.
