thanks for the info. i'm quite phobia touching anything near the input stage i'm afraid my fingerprint or my nasty flux and alcohol will screw the performance. it was a gamble buy, i thought if its truly damaged then its only for my educational purpose only. but since its somehow working, next plan... mod, create diy compensable attenuator, amplify the puny ±300mV output, anything, i got the main engine already (the hybrid) i will learn from this, but until i get a free time and "free electrons" to play with it again.