Hi I need your advice and insight on this issue.
I've recently had my vintage JBL SA640 amplifier serviced by a technician. He replaced some bad parts on the left channel of the amp.
Strange enough, when I turn it on, I hear noticeable popping and cracking noise from the right speaker for several seconds on two or three times. The initial light pop-up comes on from both speakers, and then the right one produces rather big crackling noise for several seconds.
As I listen in a bi-amp mode, the noise comes from mid-range driver (2121) of my speakers (4343).
So, I took it to the technician and had him check it, and he told me I don't have to worry, adding it will not cause any damage to the speakers.
Well, it is really annoying as I keep hearing that kind of popping/crackling whenever I turn on the amplifier,
which I have never had from other amplifiers at home I have tested with.
What might be the cause of the noise? Is it real concern? Continued popping/crackling might damage the driver?
Thanks a lot for any feedback, trouble-shooting or insight in advance.