I know this has been discussed before, but here I go
I have a B&K Ref 20 with a B&K AV600 amplifier. The two units are connected so that when I turn off the ref 20, the ref 20 turns off the amplifier. Though in reality, its more like in a standby mode than really off.
Here is the problem, when i turn off the system, the center channel makes a really low humming noise (sounds like the humm a tv makes if that helps). Like I said after I turn off the ref 20 which in turn turns off the amplifier, I get the humm, but if i then press the off botton on the amplifier, the hum goes away. Now, there is no humm when music or dialogue is coming out the the center (at least you cant here it)
This is what i did in order to fix it
1. I unplugged the amplifier from the surge protector and plugged it straight to the wall. NO difference
2. Since my amplifier is six channels, (I bought it right as the 6.1 Ex was announced) I connected it to a different channel. No difference.
3. I switch the cable that goes from the preamp to to the amplifier (center out on the preamp to channel 2 on the amplifier) No difference.
Now its not really a big deal, its just weird that when I turn of the system I still get noise. What it really sounds like is when I turn off my system, I hear the same noise for a maybe 10 seconds on my rear speakers. I was told that was residue power being send out as the system is turned off. The rears hums 15 seconds and then stop.
Unfortunately, my center hums all night long unless I turn off the amp manually.
Question,is this normal and if not any suggestions would be appreciated. Thanks
what does floating the ground on the amplifier mean?
Actually what I did was something I tried before and didn't work for some reason. I switched the speaker cable from channel 1 to channel 2 on the amplifier and of course I switched the cables from the preamp to the amplifier.
That seems to have fixed the problem and the speaker that is now connected to the channel that created the buzz does not make any noise.
But again, what does floating the ground mean. I would appreciate any detailed explanation as I would like any suggestions if this noise comes back
I guess Humey is pronounced with a long u....anyway I thought it was ironic that your problem was a HUM and your screen name was HUMey. Floating the ground eliminates ground-loop problems that often cause buzzing/humming in equipment.
One of the more frequent causes of ground loops is a ground loop hum that is typically created in unbalanced (rca type) connected systems. The typical culprits can be faulty CATV grounding, or connecting the components of your video system to different circuits of the electrical system (typically on different phases of the electrical system). A faulty channel on the amplifier or a bad interconnect cable (shielding or grounding portion of the RCA plug) may have been the problem in your situations.
Using a cheater plug (as described above) disconnects the ground from the appliance often reducing the video or audio hum. This is not a long term solution, but is often helpful in identifying the source of the hum. The next step is ascertain the cause and find a solution for that specific problem.
CATV ground loop (disconnect to ascertain if this is the source of you hum)-correct the catv grounding or insert an in-line ground loop isolator.
Place all the devices in one system on a single circuit or attempt to place all of the circuit in use on one phase.
For audio and video applications jensen transformers makes an excellent product.
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