I came across this site which shows off the innards of a Jeff Rowland Model 10 and Concentra (I & II); now this is what I call a beefy chipamp! 
http://www.shine7.com/audio/jeff.htm
Some very tidy looking valve pre-amps there too
http://www.shine7.com/audio/jeff.htm
Some very tidy looking valve pre-amps there too
