I know you want a simple answer. I've asked/researched this question many times here and I always get the same answer so I still don't really know but I'll send you where others are sent where thee is tones of info...
http://www.stompboxes.co.uk/History.html
Maybe some one will have mercy on us and give us a simple two sentence answer.![]()
Well if the DAM MKII and 1966 provide realitic comparisons I can give a subjective description other than the MKI and Mk1.5 use two transistors and the MKII uses three...usually.