for sale is my threshold s500 series 2 stereo solid state power amplifier. rca input's only but for an additional $50 dollars i'll sell you a brand new cardas adapter with a male rca into the amp and a 3 hole xlr balanced connector on the other end to run the amp in a quazi balanced mode. the silver face plate is perfect with no nicks, scratches or dents, same as the top cover and back cover. 250 watts per channel into a 8 ohm load, 500 watts per channel into a 4 ohm load and doubles down to .5 ohms. the sound is nothing short of spectacular with width, depth and placement of instruments. zero distortion, zero feed back, sounds like a single ended, or ultra linear, or triode tube amp but with power by the boat load. the reviews say unflappable and i agree 100 %. i have a box and might even double or triple box. includes manual, adapter if you want also. the amp looks near brand new. was bench tested by the original owner which i purchased it from, but now he has a hi end audio dealership and didn't have time to listen to it, so i'm the second owner with about 5 hours on it only. he also had limited hours on the amp. it spec'k out to perfection he said. i'm not sure on the size of the shipping box as of yet but it will probably be double or triple boxed. i live in pa. zip 18032 my name is john and if you have any questions you can call me at 610-264-5259 eastern standard time. the only reason i'm selling it is because after 46 years of being an audiophile and tube lover i have never heard a solid state amp sound like this so i purchased 2 more mint condition s500's in black and am using then in true balanced mono with 1000 watts per channel. i'm also selling my audio research reference 210's and getting out of tubes because of this amplifier.