The availability cheap of many good tube types that no one wants like
12 volt octal preamp types and some of the odd heater voltage power
tubes out there, the 6N7, some of the loktals, you name it.
Bill Fitzmaurice's cab designs, available for the price of a
magazine, that beat the competition badly.
Altec solid state transformer coupled power anps that make great rigs
for jazz, country, you name it. Cheap cause no one wants them.
The growth of the Dumble clone industry. It has to piss that freak
off.
R-core power transformers. Get with the program, people!
The petering out of the 7 string guitar. That low A or B throws cab
design for a loop.
Um, speaking of that... any recommendations as to which BF cab is best for
bass guitar use?