kemp@convex.com (Phil Kemp) (06/28/91)
I'm building the DC-100 MOSFET amplifier, described in Audio Amateur 2/84 with reference to the SERVO-100 ( AA 1/84 ). Old colony has subbed some parts in on the driver section of the circuit. I have a couple of questions to anyone who has built this amp. The components Q12/Q15 (BF760/BF757) and Q16/Q17(2SK216/2SJ79) have been replaced by old colony by the bipolar pair 2N3440/2N5415. Borberly recommends these as replacements for Q12/Q15. However he does not explicitly recommend them for Q16/Q17 replacement. One could make the assumption that the 2N3440/2N5415 pair replaces the BF760/BF757 pair and Borberly allows replacement of the 2S mosfets with the BF pair so therefore.... BUT 1) Has anyone used the 2N pair successfully for Q12/Q15,Q16/Q17. if so: 2) could you give me the pin orientation for the 2N pair for Q12/Q15 and Q16/Q17. ( I can do the bipolars but I don't know how to go from mosfet to biplor ) ;-( 3) If you've also had the chance to compare the original design to the 2N pair replacement, are there any sonic differences... ( good or bad ) Thanks for any help on this one... PK -- Phil Kemp CONVEX Computer of Canada Ltd. Voice:(403)-233-2815 Fax:(403)-261-2029 UUCP:kemp@convex.com