I have a mint Adcom GFA-545 (100x2 and over 40,000mf of capacitance-that is insane as my Pioneer Elite 56txi had 56,000 for all 7 channels!!) and a mint GFA-535 (extremely conservative 60x2 with 27,000mf of capacitance) for sale or trade. I would love to trade them both for a subwoofer. Something like a HSU STF-2. If selling, I would sell the GFA-545 for $200 and the GFA-535 for $105. Shipping is extra but cheap!!!