Is this normal humm ?

There seems to be an element of luck involved in how noisy Naim boxes are, and I wonder if this is due to variability in hand made products. I've owned 3 Naim amps - 2 hummed, the other is silent. I've also had 2 Unitiserves, one whirred incessantly, the other is always quiet.

I had  202/200 Napsc Hicap and had little hum in the 200 and a bit stronger from the HC. I tried many things and finally i resignated because of this funny explanation of the "element of luck". The hum was soft but annoying when not listening to music.

I upgraded to 252/250/SC and the system is absolutely silent. So either is not a problem whith my mains or the new devices manage in a better way what comes from the plug. I decided to keep the HC to power a SL but keep it off except when replaying vinyls.

I really can't buy the "element of luck" explanation but haven't have the time ( read decision/desire) to do more research and testing with my kit.

I definetely wouldn't be happy with a 252/250 humming not to say with a 500.

Going back to your case hummed at your dealer's shop?

Regards. Erich

Dinah Moe Humm?

I wonder if the lyrics of dear departed Frank will make it through moderation.

Dinah-moe
I couldn't say where she's coming from
But I just met a lady named dinah-moe
She stroll on over, say look here, bum
I got a forty dollar bill say you can't make me cum

She made a bet with her sister who's a little dumb
She could prove it any time all men was scum
I don't mind that she called me a bum
But I knew right away she was really gonna cum (so I got down to it)

I whipped off her bloomers and stiffened my thumb and applied rotation on her sugar plum
I poked and stroked till my wrist got numb
But I still didn't hear no dinah-moe

[Chorus]
Dinah-moe humm
Dinah-moe humm
Dinah-moe humm
Where this dinah-moe coming from

Done spent three hours
An' I ain't got a crumb
From the dinah-moe,
Dinah-moe,
Dinah-moe
From the dinah-moe humm

John.

Hi Ashrafs,

transformer hum from the actual 500 box would be expected, and some transformers hum louder than others. But hum from the speakers does not seem right. When you didn't have this with the 300, we can rule out a hum in the signal. I'd see a dealer.

Best,

Stefan

My NAP250.2 was as quiet as a mouse. My 250DRs and supercap all buzz briefly and not at the same time. Never seems to be common cause. Just one of those things.

Thanks everyone, will call dealer

If there is only a gentle hiss from the speakers, that is normal. If there is a gentle hum from the 500 itself, which you can hear when you are really close to it, and if there is no hum through the speakers, that is normal too.