I’ve had seat time with the GFP-750. It is a good preamplifier, that is well designed, runs very quiet, and has a bypass mode that changes the sound somewhat. One mode seems quieter, and the other mode seems a touch more dynamic.
Pick your preference. It does in fact have a single balanced input pair, and a single balanced output pair. They seem to hold a solid market value over the years, but are not so scarce that they are tough to find. There’s a black and gold style to the appearance. It runs warm, and sounds best when warmed up about 45 minutes. I liked it, but I did not keep it, as I was into my tourist phase of serial preamps. It was a good one, and if a nice cosmetic example popped up I might go for it.
On the other hand, I have come around to tubed preamplifiers, after trying a number of solid state. I have not heard that many tubed preamps, but I have discovered a fondness for hybrids as well as the tubes. It might be fun to try a Van Alstine preamp. There are audiophiles who swear by their products, the company has been around for decades, and they’re out of Minnesota.
