Help! I've got buzzing noise

I have a Magnum Dynalab MD309 integrated hybrid amp and Totem Forest Signature speakers. The speakers are 8 ohms. Tried a pair of Totem Metal V2 (4ohms) and get a strong buzzing noise from both speakers. Checked all the inputs, changed them and tried another pair of Metals. Same buzzing noise. Buzzing noise occurred both at my home and at the dealers showroom. Any ideas how to solve this problem or is my amp just not compatible?

Scott