Thanks for all your help...looks like I have something here. The two Knights I have are 40 watt deluxe stereo amps. They are integrated amps Model 83 YX 774. The tubes are 2-7025, 2-12ax7, 2-6cm8, 4-6973, 1-gz34 rectifier. All of the tubes are Mullards. They both work fine and are very quiet...no hum or hiss. Any one have any idea what each is worth in case I decide to sell one? Also, can someone tell me what year the Cornwalls are. The letter in the serial number is an S. Thanks.