audioBliss
Active Member
So a while back I bought an Apollon NCMP6350 (3 x hypex nc502mp modules inside) amp and I waited for a couple of months or so to get it. I was really excited when it finally arrived but right out of the gate I noticed that there was a fairly loud ground loop noise coming from the speakers even when no XLR inputs were connected. When connected to my AVR the noise is less but it's still there. I've had quite a long email conversation with Apollon but in the end they stopped replying and marked my order as completed. I basically have just not had enough energy to send it back or try and fix it since then but it is sort of bothering me. Apollon is of the opinion that the amp is AES-48 grounded and since my AVR is unbalanced and I'm using RCA to XLR cables that might be the issue. But the ground loop is even louder when no input cables are attached!
Is there any chance this issue will go away with a balanced AVR or should I try and send it back as a warranty issue? I mean the issue seems to be an internal ground loop. I've opened the amp very carefully and had a look and everything is very neat and tidy and looks like a very nicely put together amp with no signs of transport damage or anything. The amp was very well packaged when it arrived. The only thing that struck me as odd was that the input cables and output cables are zip tied together. However since I hear the issue without any inputs that should not affect anything. Is there something I could do myself here? Any connections I should check? The mains ground looks very solid. The XLR input connectors are grounded directly to the chassi I'm told but it's very hard to if they are. In either case I have the issue without any XLRs attached.
Any help is appreciated.
Is there any chance this issue will go away with a balanced AVR or should I try and send it back as a warranty issue? I mean the issue seems to be an internal ground loop. I've opened the amp very carefully and had a look and everything is very neat and tidy and looks like a very nicely put together amp with no signs of transport damage or anything. The amp was very well packaged when it arrived. The only thing that struck me as odd was that the input cables and output cables are zip tied together. However since I hear the issue without any inputs that should not affect anything. Is there something I could do myself here? Any connections I should check? The mains ground looks very solid. The XLR input connectors are grounded directly to the chassi I'm told but it's very hard to if they are. In either case I have the issue without any XLRs attached.
Any help is appreciated.