I recently did a restoration on a low miler SA-9900. Full recap,including ps caps. Removed all the known failure prone transistors. I ran and tested the unit for many hours. Sold it to a fellow across the country and he reported back how happy he is. The next day he reports that after he hooked up a Project tt pre amp through the AUX terminals and did some tone adjustments. It blew a fuse. Apparently it keeps blowing fuses now.Any thoughts?I have never used a tt pre amp through AUX before.