i have an external eq too and when i set my gain, i turned up the eq volume all the way up, then slowly turned the deck up until it started to sound like pew, then turned up my amp gain up until it too started to sound like pew
from then on, i use the deck volume as my main volume and use the eq on the external eq, not the eq built into my deck
from then on, i use the deck volume as my main volume and use the eq on the external eq, not the eq built into my deck