Why does my 1977 2103 sound much better than my friend's 2203x?

[Greg_L]

Yes it's the original factory PT. Is that level of anode voltage not normal for an amp of that era?

It's pretty high for that time period, but is it normal? Could be. Marshall isn't exactly known for their consistency in the 60s and 70s. They had all kinds of dealings and contracts with vendors and suppliers and also often just used what they had on hand. It's not unusual for amps in the same serial number range to be pretty different from each other.