No there is no “main in”
You would simply treat your external preamp as any other source to the 4 inputs; set the volume control on the pass to about 55 and use your other pre;
the internal line stage in the Pass is very transparent and will let the character of whatever preamp you use to shine through;
you can use the PREAMP OUTPUT to drive another amp or sub
I have this Int 250 and really like it.
You have to spend double for separates of equal power to improve; good luck
You would simply treat your external preamp as any other source to the 4 inputs; set the volume control on the pass to about 55 and use your other pre;
the internal line stage in the Pass is very transparent and will let the character of whatever preamp you use to shine through;
you can use the PREAMP OUTPUT to drive another amp or sub
I have this Int 250 and really like it.
You have to spend double for separates of equal power to improve; good luck