no synthesizers 

A tendency for certain rock bands to want to laud/trumpet/reassure die-hards that while an 128 channel mixing desk is digital, the piano plugged into channel 88 is recorded using real analogue microphones (probably digital), and all digital post-production is done without using any sort of high fidelity electronic reproduction, no matter now acoustically similar to a "real" bagpipe the digital algorithm is, it is, in fact, cat gut being heard. Despite the acoustic versitility offered by modern technology, this tiny slice of it remains verboten, especially if your band specialises in 24-stomp box digital delay guitar solos, amplifiers with on-board effects, or many of the other mod-cons the computer revolution has brought recording artists, including not having to pretend it's the hiss that makes the LP - as digital hiss can be mixed in, or that Jump and I'll Wait ruined Van Halen's awesome 1984.

Deep Purple, until it was simpler to use synths with near perfect Hammond captures - so no no synthesizers
Queen, until it became obvious that Rockpera needs all the help it can get from no no synthesizers
Boston, because, um, true to the music, or something, so no instruments that had electrics, except electric guitars, but no synthesizers
Van Halen I,Van Halen II, until Eddie got his own 5150 studio and decided whatever shot he wasn't calling - no synthesizers , he now was, so no no synthesizersDreams
Yes: everything but no synthesizers, for a while
Emerson, Lake, and palmer no synthesizers - until their need to push the envelope included algorithmic faux mandolins.

no synthesizers by Edgewaterconvention November 7, 2013