Dimmer buzzing loudly in middle position

I've just fitted a brass dimmer to replace an existing light switch on a 100W normal bulb. When the dimmer is in the off or full on position then there is no noise, but the closer I move it to the middle position a buzzing noise appears and gets louder the closer to the middle setting I get.

The last brass dimmer I fitted on a 100W bulb was four years ago and that makes no noise at all and is on the same upstairs circuit.

The differences are the model of dimmer is different (it can be switched on and off by pushing in) and this new dimmer is 2 way (but wired for 1 way).

Do you think this dimmer is faulty?

Anything else I should check?

no the dimmer is working fine, some dimmers do that, change brand and have the same as the other one you have

Any recommendations on a non buzzing brass dimmer?

I have a Wickes (where this came from), B&Q, Homebase and Focus Do It All just round the corner from me.

Sorry but any dimmer has the potential to buzz. It's magnetostriction in the core of the suppressor coil that causes it. This can be reduced by using more core material so that it isn't driven so hard. (But it can also be reduced by using inferior suppression!) All other things being equal, a higher rated dimmer (more watts) will be quieter but watch out because dimmers often have a MINIMUM power rating too!