I've tried two mods from stock with my 'Mours to drive my Theater 4's. The first was to switch the primary of the output transformer to the .625watt tap from the stock 1.25w tap. This seemed to smooth the high end a bit and add a bit of umph to the bass. The second mod was VoltSecond's Cathode Mod (the other way to parafeed) and this has had more noticable change to the sound. The top end is sweeter and less rough, the midrange is more detailed and the bass is definitely moe extended and punchy with very good detail/texture. Unfortunately, I haven't had much chance to really break in this mod so I somewhat hesitate to gush so loudly, but the distinctly audible nature of the change makes me want to feel that all is good. I'll post more later: probably on the Bottlehead Forum.
Next I plan on adding a second pair of stock output transformers after I let the Cathode Mod break in a bit.

G.

See the thread:

• http://www.audioasylum.com/forums/bottlehead/messages/43021.html