In a MusicRadar article, Tom Morello talks about how he ended up getting a Marshall JCM800 2205 50-watt head, which he uses in conjunction with a Peavey cabinet. After his gear got stolen out of his van, he headed to Nadine's Music store, and ended up buying the Marshall head and Peavey cab simply because he needed them in a pinch to record a demo, and they didn't have much other selection at the time. Morello also mentions that he found a knob combination on his amp that simply works, which he has used for quite some time. The original article can be found [here](http://www.musicradar.com/us/news/guitars/all-star-gear-tom-morellos-arm-the-homeless-guitar-and-marshall-jcm800-amp-537090).more
John Norum first recorded and toured with a JCM800 2205 when he recorded "The Final Countdown" with Europe in 1986 and toured with them a year afterwards, before leaving the group. They have been his main amps throughout his solo career and he's still using them when touring and recording with the reunited Europe, as can be seen in the 2004 rig rundown video. "I only use 50 watts because I think they sound... they sing a little bit more than 100 watts, and you don't have to kill the rest of the band with the volume and stuff like that - they think it's pretty loud anyways" "I have two JCM800s that I brought from USA. They aren’t S-certified (a security certification for electric products from Sweden). They have a volt switch between 110, 220 and 240 and also 4,8 and 16 ohm. The Swedish ones has only 4 and 8 ohm. I usually put them on 240 volts and 16 ohm" Otherwise, they're completely stock except for John having changed the tubes from EL34s to KT88s, in vein of Richie Blackmore and Mick Ronson. John can be seen talking about the amps 3:00 into the video. Fun fact: one of John's 2205s has previously been owned by his idol Michael Schenker, and Norum refused to sell it back when Schenker regretted parting with it!more
According [this article](http://www.burnsguitars.com/article14.php), Gaz Coombes used, "...a Marshall — an old JCM800, you know, a pure valve one, without any of the busy bits on that they put on them nowadays. You had two inputs and four valves. We've still got it now. Fantastic amp."more
Personally, I love the tonality of it. I picked this up after hearing Tom Morello owned this awhile back. Although I use a Marshall cabinet, instead of a Peavey, I can fairly well mimic his sound. It really sounds awesome, and just is awesome. Not much more I can say. If it's in your price range, I would go for this, or a newer JCM.