I own a heavily modified NOS version. And, I can assure you that the cabinet height is more than 6″. It is 16″. As BillM said, “there was a great amp lurking inside a good amp.” It just takes a good tech to pull that greatness out.

Mine is a Mexican green-board version, as opposed to the American cream-board. One advantage of the green boards is that they produce less hum and have better placement of the reverb circuit. I recently replaced the treble pot and modded the input jack with a Switchcraft jack that’s independently mounted. The amp had already been modded with a Warehouse speaker and a cathode bias setup. I’ve considered, and may still do, BillM’s tone stack mod and upgrade the Mexican capacitors. This is a nice little amp for the bits of electric work I do on my G&L ASAT. Most of what I play is acoustic, for which I use a Crate Gunnerson. Fifteen watts is plenty for most situations, and when needed, I can mic it through the PA while still keeping that sweet Blues Junior tone.

I agree w/ your comment regarding the pots (and input jack) attatchment to the circuit board. They are easily broken and require a bit of finess to replace. If there is a good side, it must be that the pots are cheap (under $4). On the other hand, while you are correct that the tubes are inverted, a good number of Fender (and other) amps are arranged in the same way and, in the case of the Blues Junior, there is a tube retainer which holds them in place. But the tubes are remote to- not attached to- the circuit board. The board is parallel to, forward of and above the location of the tubes. I sincerely doubt there is any adverse effect from rising heat. If you are concerned about it being an issue, when you “change it a tad”, you might consider drilling or otherwise cutting some heat relief holes in the top of the cabinet. I’m really curious, too, how your tubes “went bad just from sitting around”. I’m thinking that, if that were the case, it would not be a fault of the Blues Junior amp, as every tube amp in existence would suffer the same problem. The tubes are, after all, sealed inside a vacuum. What could possibly harm them other than use or rough treatment?