Hegel hum?

@baconboy

Please contact Hegel and explain your hum issue to their technical support staff.

i also suggest you ask your retailer where you purchases your amp.  The hum issue needs to be addressed.  

@dwest1023 

My 390 is dead silent. Even putting my ear right up on it.

Mine too...

Unfortunately I seem to have really dirty mains, had a H590 on demo, which hummed and then a loner H390 again hummed and finally my new H390 which again hummed, definitely DC issues which the Puritan drastically reduced (great equipment shame about the price). The H400 seems to have a buzz and I am wondering if its from the secondary small transformer and I am betting it doesn’t get the same mains feed as the main which has the DC blocker and is quiet. So now I think the culprit is the small transformer that I think is used to power sundry stuff. The unit was an ex demo and will contact the dealer but will give it a few days, maybe will ping Hegel direct. When I put my ear close to the amp the buzz is on the right side as you look at the amp from the front which again indicates the small transformer - perhaps it is picking up DC that the Puritan isnt killing. The H390 hum was the big transformer and the H400 is silent in that respect so am convinced its the small transformer. @baconboy do you think the buzz is the small transformer in your unit, mine is constant and maybe its just "normal" transformer hum

I have to say my Hegel H400 is dead quiet! Black as black can be. It replaced a Gold Note IS-1000 deluxe MKII that always produced a very faint hiss that was only audible if I placed my ear right up to the speaker.

Might be of use but I also have a H400 and its internal DC blocker completely gets rid of the hum that plagued my H390 (eventually the Puritan 156 solved that) The H400 is not plugged into the Puritan156 (Hegel says not to use DC blockers with the H400) but I do get this low level pulsating hum that is only heard close to the unit or sometimes when its very quiet. I asked Hegel and they kindly replied with an explanation which was that there are two small toroidal transformers for standby and the pre amp. Apparently these can be affected by high voltage and in the UK some areas have high voltage as a norm. It is not DC offset and they have looked at other types of transformer but they said it affected sound quality. As the hum is very low and sometimes not apparent I am happy enough as it isn't like the H390 and the H400's DC filter works incredibly well.