In this video I review the Fosi Audio ZP3 balanced preamp, but I’m not here to repeat the usual spec-sheet talking points. I tested it in my own setup and focused on three quirks I ran into that I don’t see many people mentioning, especially if you’re trying to use it as the “control center” for multiple sources and a subwoofer. First, I talk about the volume knob situation: the ZP3 uses a free-spinning knob, and Fosi has actually changed the newer batches to a plain knob with no marker (which makes way more sense). Second, I explain why the high-pass filter switches may seem “broken” at first—because they only work when tone controls are enabled, since the HPF is part of that circuit. Third, my biggest complaint: the tone controls don’t affect the dedicated subwoofer output, so your mains change while the sub stays the same. There’s a workaround (use line outs for the sub), but you lose the built-in high-pass filtering. Sound-wise, the ZP3 is clean and transparent in my chain with the V3 Monos and ZA3, and the volume memory per input is a genuinely useful feature—especially when switching between low-output sources like my phono preamp and normal sources without getting a surprise volume jump.