Only a few months old. I bought it new, used it a handful of times, decided I have too many amps. This is what SWR says:
"Not too much and not too little – our 550x is just righteous, providing world-famous SWR® professional tube preamp tone and 550 watts of full-range power in a convenient two-rack-space configuration. Loud enough for just about any gig, and simple enough for the most plug-and-play bassist, with our exclusive Subwave sub-octave effect onboard, the 550x is a powerful tool in any bassist’s arsenal.
Features: 550 watts @ 4 ohms, classic SWR tube preamp with Aural Enhancer™, Subwave, studio-quality three-mode XLR out (direct, direct + Subwave, line) with ground lift and level pad, three-band active EQ with variable midrange, automatic limiter with defeat option, side-chain effects loop with blend control, tuner send, speaker on/off switch, Speakon® and 1/4” speaker outputs. Footswitch for Subwave effect included."
A few scratches on the top. Otherwise like-new condition. $425 shipped to CONUS.
