Forgive me for even saying this- & I realize I've probably committed a mortal sin in the eyes of many 'wreck owners, but does anyone have a schematic for an effects loop?  I wired one into my 18w TMB Marshall clone with excellent results- it would just be good to add a little reverb/echo post the pre-amp...

Can I be one of the first to wish all on this site a Happy New Year...

Thats why it'd be better to ask Nik, no risk of a flame attack!  And I bet Nik has been asked for one before so will likely have the layout already sorted.

Guys-

Actually in the end I 'saw the light' & after some experimentation found my delay pedal sounded fine in the front end after all- kind of cool with the ludicrous amount of compression/gain on tap from the Expression that I could turn the delay level right down and the distorted echoes just made it sound like an old tube/tape echo!  You were right to advise me against further mods- the amp sounds so sweet as it is... I have made a true bypass for the delay to avoid tone sucking & actually built a new 'mini me' pedal board with just the delay / tuner / clean boost pedals on it, and now just re-discovering doing everything from the guitar... got my first gig with the Expression tomorrow- I'm looking forward to frightening the drummer!