This is my first Marshall. A 50 watt head I bought back in 85 +/- I remember the day well. I was so excited to play my first Marshall. I carried it into the jam room placed it on a 4x12, plugged it in, turned it on and 10 seconds later the magic smoke came out the back of the amp. After bringing it to a Tec I got the story of loose tube sockets and blown transformers. I was a kid and knew nothing, but I knew it had to be fixed, I said go ahead. The Tec guy says these amps run hot you should get a fan installed in the side of the cabinet. So I say okay. Then the Tec asks Do you want the EVH mod? Duh? It's early 80's doesn't every kid want the EVH mod? So I say okay. The problem is I don't know what this mod did and I never ended up using it. There is a knob on the back that I pull out and turn it up or down and is supposed to do something But I never noticed much difference. If it were today I wouldn't have paid for that or the fan installed in the side of the head that I never used anyways. live and learn, right? Anyways after that this amp has been rock solid, I never so much as changed a tube or looked under the hood. It's been perfect. The power cord finally came to it's end, so I am going to cut a big hole in the back to put a modern day plug in and may want some advice in disconnecting this EVH mod. I will post pictures when the time comes. Till then, why is this head so small? was this intended for 4x10 cabinet? you wouldn't call this a Plexi would you? Is it JMP even though it don't say JMP? is this a 1987 model? I wasn't sure if this is considered "Vintage" But after looking around I think I'm safe.