NAD 326 headphone noise issue ?


I have a problem with the headphone!
When i turn on the amplifier (Nad 326bee) using headphone, there is a noise (like a "bumm"), and when i turn it off, after about 2 secounds there is another noise like a siren, then a clipping sound.
It is normal or an issue (i heard this on 2 amplifier with 3 different headphones)?

Thank you very much!
I'm guessing that the headphone jack does not have a mute circuit when turning the amp on/off.

If so than what you are hearing are the noises that amp's typically make during turn on/off but which we are spared from hearing (through the speakers) as most amps mute the speaker outs. The clicking sound that most amps have after a few seconds of being on {or immediately upon turning the amp off) is the sound of the relay unmuting or muting the speaker outputs.
Some integrated amps doesn't have a well designed headphone output section, that's probably the cause of your issue.

Which headphone models are you using?