It uses the INA163, a non pin replacable version of the INA103, the chip used in the Grace pre's. Too bad they didn't use the similar INA217, a pin compatable version that has nice subs from Analog Devices and that corp.

Not all is lost here. Replace C1/2 with Panasonic 47 uf 50v FM series. Add a small film bypass cap to those. Replace the too small 1 uf C38 with a 47 uf 25v FM. Replace C38 with a Wima MKP-1 .1 uf 250v from Mouser. Add a 47 pf mono ceramic cap across R-17 to stabilize the opamp. Replace the 22 uf output caps, C21,14,29,24 with Panasonic 220 uf 25v FM series.

Pop in some machine sockets and replace Z2 with either a National LM4562 or a National LM6172. Replace Z3 with the 6172.

Jim Williams
Audio Upgrades