The subject amp is a Guild "Thunderbass 1," 50 watts, 2 x12...NOT "Quantum," 100 watts, 2x15, as was advertised. But it is confusing as they are all very similar and obscure to an extent. And the word "Quantum" really does not signify anything in particular, was more ussed in advertisments than anything. You could have a 100 watt Thunderbass that is not necassarily the Quantum, but I am not trying to start a whole thread about that. The seller did a good job with what he knew, printed out the schematics and such of what he could find from the internet without going too bezerk. Tubes are 8417's. it ultimately needs new speakers, but no longer needs a new home. a good score was too close to pass it up. Also looked up prices a little more and I do concurr actually for all Guild amps, seems prices are just all over the road. some are still cheap and others are into the "true vintage price point" now that we have arrived in 2013/2014. get em while u can! nothing like a Guild tube amp. be sure you know what you are buying though. some tubes are discontinued. Thanks to this forum and some "extended members" I am doing good with Guilds recently. time for a few others to get in on the action. They are out there!