I'm trying to understand the circuit differences between some of the Blackface/Silverface fender amp models. Some of them seem close to identical! What's the difference between these 2x6L6 models? Bandmaster Pro Reverb Vibrolux Super Reverb And what's the difference between these 4x6L6 models? Showman Dual Showman Twin All of these seem to feature the same tone stack, LTPI driving 6L6s, tremolo, etc. There are some differences in whether or not there's reverb in a few, but not all. And one additional question - I'm wondering, is there an amp which is exactly like a blackface twin, but a 2x6L6 instead of 4x6L6?