Your story is unfortunate, but not at all surprising. There's a big difference between buying tubes, for the sake of buying tubes, and buying the right component for your system.
"Counting the replacement components, that's 8 tubed products - and not one has worked."
That's probably not true. Some of it looks like poor matching.
"They sent me a new one, but I was getting significant distortion. Turns out even the lowest gain setting was too high for my integrated amp. Went to a SS phono amp."
Tubes had nothing to do with that problem, or your integrated amp. It was a mismatch between your phono preamp and your cartridge. Blame that one on your dealer, and find a new one. A mistake that simple is inexcusable.
" Tried a single ended tube integrated. Had a hum problem that was audible from 30+ feet away. Shipped it back for repairs. Came back to me and broke down within the week. They sent me a new one - hum was still there although not quite as bad as the first unit. Went back to my SS integrated."
Probably nothing wrong with it. An SET shouldn't have been your first tube amp. You need to match your source and speakers very carefully. If not, its easy to get a hum.
As for the rest of it, there's no way to tell what happened without more info. Most likely the products were either low quality or mismatched.
