Many thanks to all the participants of this forum. I am trying to use all your help and have some answers and more questions to ask.
Ktsteamer:
It is an interesting possiblity. I indeed have the room's lighting on a dimmer switch in a different room, which is exactly above the listening room. In my experiments, I made sure that it is swithched off, but I wonder if, even so, it may still creat a buzz???
Mzn50: I plug them all into one power surge protector and
line conditioner. I tried the cheater and checked the polarity too. I also connected the chassis of the preamp to other various components. The crossover I mentioned is in the separate power amp for the sub, that is, not in the preamp in question. So, I can run the full range signal from the preout in the preamp, and then can cut it off below 80hz, by engaging the sub amp crossover. This kills the buzz in the subwoofer speaker. Hence, it is not a 60hz ground loop hum?
Thanks.
Ktsteamer:
It is an interesting possiblity. I indeed have the room's lighting on a dimmer switch in a different room, which is exactly above the listening room. In my experiments, I made sure that it is swithched off, but I wonder if, even so, it may still creat a buzz???
Mzn50: I plug them all into one power surge protector and
line conditioner. I tried the cheater and checked the polarity too. I also connected the chassis of the preamp to other various components. The crossover I mentioned is in the separate power amp for the sub, that is, not in the preamp in question. So, I can run the full range signal from the preout in the preamp, and then can cut it off below 80hz, by engaging the sub amp crossover. This kills the buzz in the subwoofer speaker. Hence, it is not a 60hz ground loop hum?
Thanks.