Unexpected preamp needed- return policy important

I need suggestions for a preamp. My amp is a Halcro MC20, powering Newform Research hybrids. I have a Cary 306 SACD coming next week.
Several months ago I bought an Atma Sphere preamp for the Halcro. While it sounded wonderful, there was a persistent buzz from both speakers. I tried everything to diagnose the problem, all without success. The kind Audiogoner I bought it from took it back. The pre worked perfectly in his system. So I hooked up an old Ah Tjoeb/Marantz player. No feedback. So I figured I would get a CD player with a volume control. My research was detailed but sloppy. I ended up buying a used Cary SACD 306 assuming it had a volume control. Just discovered that the Cary has no control. So I have to deal with the preamp issue again.
Out of concern that I will end up dealing with feedback issues again, I want to start the search with companies with a return policy. I know that buying new is not the best bang for the buck, but I would prefer not to face the same distortion issues without that safety net. So, suggestions? And thanks.
D1