If Sanyo ever had a presence in the US coast, was a brief one. It makes a series of electronics products, most of them are for other markets like Europe, South America, Asia etc...It does not mean that is a bad brand, simply it does not have presence here. I have not heard about the preamp you are talking about, but when I was growing up in South America, they used to offer very interesting mini system and the like, I can recall that they looked innovative, soundwise, in comparison with what I have now, I doubt it was that good. It will suffice with your budget. If you are scrounging so much to get a decent sound preamp, the Sanyo will do, for now. I doubt that other sub $500 preamp are much better, although I do have a Sumo Athena MKI, vintage 1989, that is worth $200 in the used market and it sound awesome, eventhough I have another preamp that goes for about $1500, used. Keep it and save some money until you can get something worthwhile.
PAUL
PAUL