Son of Bovril said:The SVT6 PRO in fact has a lower output than the 4 (just because the number 6 is higher than the number 4, it doesn't make it a bigger or better amp...)
They are quite different.....
4PRO, 1200 watts , all solid state power amp, tubes in pre.
6PRO 1100 watts , hybrid tube-driven mosfet amp, tubes in pre.
The power difference is minimal, the power amp technology involved is the big difference, and the preamps are somewhat different.
The 6PRO is smaller, also.