DL4 distortion problem

["cameron street" <c.jas@optusnet.com.au>]

I was using a dl4 and a headrush.
but changed to 2  dl4's.
it was quieter, and better all around, BUT!!!!
noticed a slight distortion on the top end,
Gain adjustment on amp won't change much. 
so 1 dl4 is cool, 2 is too much signal.
What's the go?
please help.  i bought the 2nd DL4 instead of
paying my car rego.  Have i made a mistake!
cam