You mean a dbx 166 (saw the main subject line
)? I have an original model (no A or X at the end) that I love and run on the main output stage - mainly for the limiter but use a tad of compression as well. I think I paid over $100 for mine used a few years back. If it is this model & in good working condition, then $75 is still worth the price. It would be good on the vocal mics as well.