OK, this is all things I've heard mixed with some personal observations, but here goes. Correct me if I'm wrong about any factual details...
I've had work done by Mike Pasnak years ago when he was apprenticing with John Macintyre (Musitech, next door to Axe until the late 90's or so). John is THE all time amp guru of Calgary as I understand it, having built stuff for David Gilmour and other superstars. Supposedly Mike learned everything he knows from John, who left behind amp service years ago to go work for Lexicon (I think) designing circuits.
I'd like to throw in my 'two cents' for what it's worth.
In the mid-90s, after reading John Macintyre's article in Guitar Player mag on how to mod an old Fender Bassman, I was pleased to notice he was in fact located in Calgary.
After first contacting him for his business address I shipped him my '65 Fender Deluxe Reverb to have his company perform the modifications as outlined in his GP article. I included a cheque for the work (about $450).
The work was done and the amp returned in a reasonable amount of time and it sounded great but I had a couple of complaints that went unaddressed:
1 - No schematics were ever supplied for what is essentially a different amp; and
2 - The "fat switch" circuit -for which I had paid $39 as part of the total price of the mod -had not been installed as requested.
But the thing that pissed me off the most was something I only came to notice some years later: that my '65's original Jensen speaker had been replaced with a stock Fender speaker. Oh well, what are ya gonna do, eh?
Now, I don't accuse John Macintyre of personally of swindling me out of my vintage Jensen speaker but nonetheless, someone from his company did. That, and the failure to provide the fat switch I'd paid for, certainly left a bad taste in my mouth.
I'd be interested to hear from anyone else who might have experienced a similar problem if only just to have somebody to commiserate with.
Notwithstanding the above, the Macintyre mod was a tremendous improvement on the amp's original design and in any event, I fully intended to replace the original speaker with a 12" JBL I had knocking about the place. The coolest aspect of the Macintyre mod was that the amp remained aesthetically the same -it continues to look like a simple Fender Deluxe Reverb but it sure doesn't sound like one!!
If anyone knows the whereabouts of John Macintyre I'd still like to get my $39 bucks back; though I'm not holding my breath for the return of my Jensen speaker.