SAM 82 mixer

Hi People, I just got a nice SAM 82 mixer (SATT brand I think) made in Sweden. Its very nice sounding!! 8 mic pres w/hi-lo eq, 80Db gain, phase and phantom, 2 sends pre/post and pan I opened it and I`ve found it use lundahl 1515 trafos on inputs, custom trafos for outs and the channels are using SN 72709P except for channel 4 using NE5534AN, could be better replacing all the channels with 5534s? Also does anyone have info on this little beauty?? Thanks! Synthi.