I have just added a K2 power amp to my system (see sig for details) and am having a problem with noise. I have been using the Beresford as a pre and after adding the power amp there is a noticable background noise. It is not a hum it`s almost like a slowed down version of the noises a dial up modem used to make while connecting,high pitched beeps etc. The noise is noticable at the begining and end of tracks and in quiet passages,if the music is paused or stopped the noise stops,I`ve unplugged and re-seated all connections but the noise continues. As a last resort I reverted to using the Beresford solely as a dac and using the K2 integrateds pre section and problem solved or so I thought but there is still a noise.The new noise is far less noticable and is a constant high buzz from the tweeters even with no music playing but you have to put your ear close to the speakers to hear it. I would like to continue using the Beresford as a pre if possible as it gives a performance boost so any suggestions as to what might be causing this will be most welcome.
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Noise problem after adding power amp
- Thread starter basshound
- Start date
John Duncan
Well-known member
- Jan 8, 2008
- 2,034
- 30
- 19,720
John Duncan
Well-known member
- Jan 8, 2008
- 2,034
- 30
- 19,720
Is the laptop plugged into the mains and connected to the Beresford via USB? What happens if you let it run off the battery?
Have you considered trying a Tacima CS929 for everything except the power amp? You can plug the DAC/pre into it. Try to ensure that cables are tidied and not tangled or laying over each other too much; I use cable ties to bind together my I/Cs. You could also consider trying shielded mains cables. Also make sure speaker cables are not coiled up into neat circles.
Laptop is connected wirelessly to Airport Express and the AE is connected to the dac via optical,noise is there when plugged in or off battery,know where your coming from as the noise seems electronic in nature rather than an elecrical hum/buzz
igglebert:Have you considered trying a Tacima CS929 for everything except the power amp? You can plug the DAC/pre into it. Try to ensure that cables are tidied and not tangled or laying over each other too much; I use cable ties to bind together my I/Cs. You could also consider trying shielded mains cables. Also make sure speaker cables are not coiled up into neat circles.
I have shielded mains cables and the noise only started after adding the power amp but with an extra pair of inters and another mains cable the area behind the kit is a bit of a mess so would do no harm to tidy it up.
I have shielded mains cables and the noise only started after adding the power amp but with an extra pair of inters and another mains cable the area behind the kit is a bit of a mess so would do no harm to tidy it up.
John Duncan
Well-known member
- Jan 8, 2008
- 2,034
- 30
- 19,720
basshound:Laptop is connected wirelessly to Airport Express and the AE is connected to the dac via optical,noise is there when plugged in or off battery,know where your coming from as the noise seems electronic in nature rather than an elecrical hum/buzz
Right, not the laptop PSU then (which I've found is pretty typical when they're mains-driven), since you've done all you can to isolate it from the audio.
In which case I'm with Ig - interference from somewhere. Try swapping boxes round in case, say proximity of big transformer of new power amp to delicate innards of preamp is wreaking havoc - try power amp on top and Beresford on bottom, for example.
Right, not the laptop PSU then (which I've found is pretty typical when they're mains-driven), since you've done all you can to isolate it from the audio.
In which case I'm with Ig - interference from somewhere. Try swapping boxes round in case, say proximity of big transformer of new power amp to delicate innards of preamp is wreaking havoc - try power amp on top and Beresford on bottom, for example.
JohnDuncan:basshound:Laptop is connected wirelessly to Airport Express and the AE is connected to the dac via optical,noise is there when plugged in or off battery,know where your coming from as the noise seems electronic in nature rather than an elecrical hum/buzz
Right, not the laptop PSU then (which I've found is pretty typical when they're mains-driven), since you've done all you can to isolate it from the audio.
In which case I'm with Ig - interference from somewhere. Try swapping boxes round in case, say proximity of big transformer of new power amp to delicate innards of preamp is wreaking havoc - try power amp on top and Beresford on bottom, for example.
Yeah,I was kind of thinking that,noise is definate electronic beepiness so will have swap round tommorrow and keep the 2 as far apart as possible,thanks for the suggestions
Right, not the laptop PSU then (which I've found is pretty typical when they're mains-driven), since you've done all you can to isolate it from the audio.
In which case I'm with Ig - interference from somewhere. Try swapping boxes round in case, say proximity of big transformer of new power amp to delicate innards of preamp is wreaking havoc - try power amp on top and Beresford on bottom, for example.
Yeah,I was kind of thinking that,noise is definate electronic beepiness so will have swap round tommorrow and keep the 2 as far apart as possible,thanks for the suggestions
Hi basshound,
The sounds your hearing is interferance from the Laptop hard drive motors spinning up and stuff, (I think its RFI), if I turn my amp right up I get the same, and the PC Sub/Speakers do the same as well, even with headphones. its a bit like old car radios picking up interfearence from the alternator. moving your laptop further away from your amp may stop it or fitting an rfi clamp ie: http://www.mauldroppers.com/showthread.php?7104-STOP-TVI-RFI-Interference-in-Home-or-at-the-Neighbors
hope this helps!
The sounds your hearing is interferance from the Laptop hard drive motors spinning up and stuff, (I think its RFI), if I turn my amp right up I get the same, and the PC Sub/Speakers do the same as well, even with headphones. its a bit like old car radios picking up interfearence from the alternator. moving your laptop further away from your amp may stop it or fitting an rfi clamp ie: http://www.mauldroppers.com/showthread.php?7104-STOP-TVI-RFI-Interference-in-Home-or-at-the-Neighbors
hope this helps!
JohnDuncan:
Try swapping boxes round in case, say proximity of big transformer of new power amp to delicate innards of preamp is wreaking havoc - try power amp on top and Beresford on bottom, for example.
Got round to doing as you suggested JD and swapped boxes with the power amp on top shelf and Beresford on the bottom and the noise has stopped with the Beresford being used in pre mode again.So must have been interference from the power amps` transformer or whatever and a bit of distance cured it.Funny how it didn`t work the other way round with the Dac on top and power amp on bottom. A very annoying problem with a simple fix,thanks to all who made suggestions.
Try swapping boxes round in case, say proximity of big transformer of new power amp to delicate innards of preamp is wreaking havoc - try power amp on top and Beresford on bottom, for example.
Got round to doing as you suggested JD and swapped boxes with the power amp on top shelf and Beresford on the bottom and the noise has stopped with the Beresford being used in pre mode again.So must have been interference from the power amps` transformer or whatever and a bit of distance cured it.Funny how it didn`t work the other way round with the Dac on top and power amp on bottom. A very annoying problem with a simple fix,thanks to all who made suggestions.
Hi - It looks like RFI interaction by the sounds of what you say.
What is the order / arrangement off the mains source?
As others have said tidy up the cables and if you are running the mains input off one 13A plug/extension on the ring main, try putting the high current draws 1st in the line followed by the rest.
What is the order / arrangement off the mains source?
As others have said tidy up the cables and if you are running the mains input off one 13A plug/extension on the ring main, try putting the high current draws 1st in the line followed by the rest.
I had a similar issue a while back and in the end i found it was caused by power cables being too close to each other and/or interconnects. By fiddling with the position of the cables and moving then away from each other the hum stopped.
Did as Trevor suggested and rearranged the plugs and plugged the power amp into it`s own wall socket and thought that had solved it but the noise started again after about 15 mins.,changed back to using the Beresford as purely a dac and the noise goes,there is a slight buzz that wasn`t there before the addition of the power amp but it`s only audible with no music playing and ear right up against the tweeter.
Strange thing is the electronic type noise continued even with the dac switched off although it did change in pitch. I am resigned to using the Beresford in dac only mode which is frustrating as there is a performance gain in using it as a pre.Thanks to all who tried to help.
Strange thing is the electronic type noise continued even with the dac switched off although it did change in pitch. I am resigned to using the Beresford in dac only mode which is frustrating as there is a performance gain in using it as a pre.Thanks to all who tried to help.
Right one last try, Hooked up the Beresford in pre mode to the power amp only with integrated turned off and noise starts after about 15 mins,tried it with just the integrated and power amp off i.e. the original set up before adding the power,and noise has gone.
This prety much proves to me that there is something in the power amp that the Beresford doesn`t like so any further suggestions most welcome,if it is some kind of electro-magnetic or whatever interference is there some way of shielding the dac from it ?
This prety much proves to me that there is something in the power amp that the Beresford doesn`t like so any further suggestions most welcome,if it is some kind of electro-magnetic or whatever interference is there some way of shielding the dac from it ?
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