Do you have hard to drive vintage speakers? Or do you just want lots of power on tap? Then this amplifier is for you! Adcom is a brand that is highly regarded among the vintage audio enthusiasts. While the aesthetics of the brand is planted firmly in "black box" territory, it's performance, reliability, and build quality can make you forget all about its looks. The tonality of this amp could best be described as invisible, and all the color in sound you hear is from your preamp, input device, and speakers. That's a large part of why people love this amp. Of the original 555, and the 555 II, the second iteration is the one to have. Some of the upgrades found in the II over the original is lower distortion thanks to slightly better internal circuit design, grounding is now isolated from ground on speaker terminals, internal wiring is now oxygen free copper, all the fuses are accessible from the back instead of inside the case, larger heatsinks, as finally a larger toroidal transformer, and thermal protection. The 555II produces a very underrated 200w/ ch into 8 ohms, or 325w/ch into 4 ohms both channels driven. Those specs fall far short of typical ACTUAL power output which is closer to 260-290 into 8 ohms or 400-425 into 4 ohms. And the THD is in the basement at 0.02%. If that power isn't enough, you can bridge this amp into a monoblock and send 350w into 8 ohms or 650 into a single 4 ohm load. As you can see in the pictures, this GFA-555 II is in wonderful condition with no big scuffs or scratches or bent fins. Auditioning available for serious buyers.