Tone Silverface vibro champs generally run about 350-550.. the 65-82's all had the same circuit but cabinet materials changed in 72-73 , 64-66 blackface cosmetics changed to silverface in 67with the 67-69 having a aluminum trim around the grill cloth commonly refered to as dripedge .Late 69 models lost the dripedge and the champ and vibro champ stayed the same till 82 when a re-designed blackface look appeared ... bottom line is they all sound great its a pretty simple little amp with an amazing sound .. Just a note Tone .. ebay prices are pretty high I've seen silverface vc's go for as high as 800 bucks and nice ones from before 73 with the pine cabinet in the 350-450 range ,they take pedals great , and are a sweet recording amp .6S9L