Still have interferance!

[12.1]

Hi all, recently got a pair of B&W 684 stereo floor standers - beautiful. Only problem is that I dont yet have an amplifier and so am using my mates old Rotel RB960BX+RTC950TX poweramp/receiver combo until I get my hands on one. However I get quite a lot of white noise coming through the speaker - no matter what inputs are selected. This increases with volume. I checked out some other threads on the problem and have already moved the power sockets from a multiplug adapter straight to the wall - massive improvement - all the HF part of the noise seems to have gone. However I still have a decent amount of hum/hiss (which now only slightly increases with volume). Was using this amp before through a pair of homemade floorstanders and this noise was not that apparent but obviously the 684s are more responsive. Can anyone suggest how to get rid of this noise??

cheers

 

[highfigh]

Hi all, recently got a pair of B&W 684 stereo floor standers - beautiful. Only problem is that I dont yet have an amplifier and so am using my mates old Rotel RB960BX+RTC950TX poweramp/receiver combo until I get my hands on one. However I get quite a lot of white noise coming through the speaker - no matter what inputs are selected. This increases with volume. I checked out some other threads on the problem and have already moved the power sockets from a multiplug adapter straight to the wall - massive improvement - all the HF part of the noise seems to have gone. However I still have a decent amount of hum/hiss (which now only slightly increases with volume). Was using this amp before through a pair of homemade floorstanders and this noise was not that apparent but obviously the 684s are more responsive. Can anyone suggest how to get rid of this noise??

cheers

Does this power amp have input level controls?

White noise isn't hum, it's only 'hiss'. You won't get hiss from the electrical supply, only from components in a piece of equipment.

Disconnect the input cables from the amp and turn it on. You should hear no noise. Turn the amp off.

Connect the receiver's output to the amp's input, turn the receiver on and set the volume to minimum. Turn the amp on- you should hear no noise. If you hear hiss, the receiver has a problem. This is connected via a real preamplifier output, right? Using the Record output and a power amp's input level controls doesn't work well.

If you hear hum, you have a grounding issue.

If the speakers' high frequency response is much better with the newer speakers, you will hear noise that wasn't apparent before but a speaker won't cause hum or hiss.

 

[12.1]

thanks highfigh. yes its a real pre amp connection. Have done what you said and with the volume at zero there is no sound but as I turn it up the noise/hum get quite bad. Phono input(not connected) sound like the ocean(quite soothing actually). Aux input is interference as there's a certain frequency hum and the cd input is worst - mixture of HF wine + white noise. I am guessing these are all grounding/wireing issues - the speaker wire I'm using is quite old so I think I will replace that first and hope the new amp I get does not have these problems...

 

[highfigh]

thanks highfigh. yes its a real pre amp connection. Have done what you said and with the volume at zero there is no sound but as I turn it up the noise/hum get quite bad. Phono input(not connected) sound like the ocean(quite soothing actually). Aux input is interference as there's a certain frequency hum and the cd input is worst - mixture of HF wine + white noise. I am guessing these are all grounding/wireing issues - the speaker wire I'm using is quite old so I think I will replace that first and hope the new amp I get does not have these problems...

I can't think of a way the speaker wire will make a difference. Do you have headphones? Disconnect the receiver from the power amp and listen, using all of the inputs. I'm pretty sure the problem, is with the receiver.

 

[lsiberian]

I know I had a problem like this with an old receiver hooked up to my speakers. I replaced the receiver and it went away. I'd significantly upgraded the speakers and as a result the problem was audible. I suspect the same here.