The 6100 has 3 separate channels (quite ). This let you tweak your sound with different tubes. With the TSL100, sounds 2 & 3 share the same tubes, and, as for the JCM 900, even the eq is shared by the 2 channels so clean is usually unusable. So, as it is basically the same poweramp design , you have to compare preamps. The 6100 has a very nice clean, can crunch just a little or more and let you solo with far enough drive. It is the great winner of the preamp section.