Hi,

Home-made 10" subwoofer unit, connected to Kenwood AV-Receiver model
KRF-7050D. it has it's own PS and internal, DIY 2x10W amp kit.
When i turn on the power, the unit produces a loud hum, and after about 2
sec. the hum is quiet but still present. when i mute my receiver, the hum
goes away, so i suspected the input is bad. the thing has proper grounding.
i replaced the PS, as i thought it inserts hum into the system, but no good.
after checking the amp there were some loosen electrolytic caps (cold
solder), which i re-soldered (i have this amp for about 12 years or so). i
soldered another electrolytic cap to the input side of the amp (100uF, 10v)
and tested it - now the hum is gone completely, but along with the hum went
the sound it should produce.

anything else i should check? / i've done wrong ?