how to set bias corect ?
how to mesure it ?
schematix = http://www.produktinfo.conrad.com/d...158-sp-01-en-Fidek_Endstufe_2x1500W_4_Ohm.pdf

many hx

 

I would say, 3PR2 sets the Zero Speaker voltage output, 3PR3 sets the current, what ever the current value is will be given in the service manual.

 

thx Dodgydave
but i have no service manual .

 

Then i would set it to the minimum current , and using a Scope increase it slowy until the crossover distortion disappears, keep watching it for about 30mins to be sure