why distortion and what is the cure

Thanks so much Greg - the Ibl line looks interesting and they are only about 40 mls from me. I have seen a 2nd user pr of Linn Tukans but i cant find out the sens. of them. Would they be a good match ? Great reviews and a clean detailed sound by most accounts.

Thanks Joe
I am using CD as the source. The sound with both amps is fine at low volume but turn it up and yuck!! Have spoken to Sugden who suggest that A)one or two of the power transistors may have gone or B)the speakers arent sensitive enough for the amp. Amp is 12 watts class A and speakers are as above.I love the sound of the amp and really dont want to change it if i can help it.The speakers can go out with the trash. So cmon guys - solutions and speaker suggestions (pref F/S with waf)

Thanks guys - yes i think the speakers are inefficient for the amp(thx edesilva) but am sending the amp to Sugdens for a service and they can test it.Fatparrot- The speakers were made as the front end for cinema setups and were manufactured in 2000.I naievly let the salesman talk me out of a pair of Mission for these and regretted it since. What speakers can anyone suggest for a 12 watt amp please? (bear in mind $600-700 second hand limit!!!) Sugdens suggest Totem arro, or snell ? Cant find Snell at all here and the totems are hard to come by.

Hi Guys - thanks so much for your answers - today i took the MFidelity to a used hi fi shop and ran it thru 4 sets of speakers and no real distortion at volume so my guess is that the speakers are kaput !!
I will definately keep the Sugden as i love its sound - i think i will have a hard time finding speakers to match it that i can afford tho. Greg - which triangle and are they expensive?