To a certain extent it's all been done. Depends on how different you mean I guess. For me, to sound completely unique, it's going to be so different that some will think it is broken. Otherwise, a little different and some will just think 'sounds like a variation of (insert brand & model here)'. One thing I did think was quite unique were the Philips tube hi-fi units that did not use output transformers but used custom high impedance speakers instead. Now that is something.