eddie pugh
pfm Member
Ive just installed a pair of NCC220 in my Avondale modified NAP250 and the sound is quite amazing. Quite an upgrade on the NCC200s which I've been more than happy with for over 10 years
The bass performance is noticably better than the NCC200's so much so that a low grade earth loop that I had mistaken for quite some time as the odd lorry grinding its way up the hill at the end of the garden is now revealed as a definite very low frequency earth loop or maybe some weird electromagnetic pickup in the myriad cables. I disconeccted all input cables appart from the AV and the hum is still present It disappears completely when I select AV or press mute so what does that say Electromagnetic pickup ?
Now I know that once upon a time all naim kit was designed such that the CD player provided a single point connection of signal and chassis mains earth. I checked my CDX and indeed the earth link is present via a small resistor.
To try and get rid of my earth loop i made up a cable connecting just the earth pin on an MK mains plug to the earth sheild on an RCA phono plug. When I use this cable to connect one of the aux1 phono inputs to a wall socket my low frequency hum is drastically reduced to a very acceptable level. So what gives with the current Naim earth system. My kit is all fed from a Grahams 6 headed hydra fed from a single wall socket Is this not sufficient to ground the system properly and elliminate earth loops.
I noticed that ther is a signal ground connection on the back of the NAC252 yet no mention in the manual as to what it is for, Any ideas?
I should add that I am not cloth eared and more often than not listen to the system with TV or Squeezebox digital stream via a TAG AV32Rdp dac/processor via the NAC 252 AV line level input which has an absolutely silent bacground. I've even started using the DVD32r as a CD player instead of the CDX The Tag DVD 32 and AV32 combo are way better than the CDX but then the CDX is getting on a bit
The bass performance is noticably better than the NCC200's so much so that a low grade earth loop that I had mistaken for quite some time as the odd lorry grinding its way up the hill at the end of the garden is now revealed as a definite very low frequency earth loop or maybe some weird electromagnetic pickup in the myriad cables. I disconeccted all input cables appart from the AV and the hum is still present It disappears completely when I select AV or press mute so what does that say Electromagnetic pickup ?
Now I know that once upon a time all naim kit was designed such that the CD player provided a single point connection of signal and chassis mains earth. I checked my CDX and indeed the earth link is present via a small resistor.
To try and get rid of my earth loop i made up a cable connecting just the earth pin on an MK mains plug to the earth sheild on an RCA phono plug. When I use this cable to connect one of the aux1 phono inputs to a wall socket my low frequency hum is drastically reduced to a very acceptable level. So what gives with the current Naim earth system. My kit is all fed from a Grahams 6 headed hydra fed from a single wall socket Is this not sufficient to ground the system properly and elliminate earth loops.
I noticed that ther is a signal ground connection on the back of the NAC252 yet no mention in the manual as to what it is for, Any ideas?
I should add that I am not cloth eared and more often than not listen to the system with TV or Squeezebox digital stream via a TAG AV32Rdp dac/processor via the NAC 252 AV line level input which has an absolutely silent bacground. I've even started using the DVD32r as a CD player instead of the CDX The Tag DVD 32 and AV32 combo are way better than the CDX but then the CDX is getting on a bit