- Jan 9, 2013
Well....I am sorry to say but my smsl 1955+ dac that I have been running has started to eat opamps. I am not sure if it has anything to do with the quality of the opamps that came with it (Chinese copies.) or that the design is bad. I am not an electrical engineer but from what I have been researching and from the advice I get from my electrical engineer friend the opamps seem to be cooking themselves. I am assuming that if the circuits are not optimized for the opamps, they begin to oscillate and generate heat and also noise. For me it was a ringing in the background. Initially the JRC 5532DD burned up..noticed the edge formed a white power deposit. So I replaced it with a LM4562. Ringing went away and sounded great for a while. Then after I forgot to shut off the DAC one night and woke up the next morning to find the ringing had returned. I opened up the unit again to find that all three opamps, LM4562 and the pair of AD 275 with white deposits along the edge. The sound was terrible.....basically I knew at that point that all three were trashed. My next step now is to order replacement opamps from Arrow electronics(sugguested supplier from TI website) here in the US. I also have samples direct from TI (LM4562). So I try a pair of AD 275 and also see what a pair of bb2134 will do. As for third single opamp on the board I will try the lm4582 sourced from TI and compare with the BB2604 to see what happens. Anyone out there with similar problems? Any other electrical engineers out there with ideas? Keep you all update as soon as I get my opamps in and trial them out. Thanks.