Hmm, I didn't try that. Something to consider. I liked the eq points when I had a Tone Hammer amp years ago, so taming the boost and cut would probably help.When I wired up an Aguilar OBP-3 in 18v I thought the boost/cut was too extreme. Rewiring to 9v solved the problem and I really like the preamp now. Mid is set at 400hz. Active passive switch revealed a true bypass to my ears.