Just from memory, LM 518 utilized 845 tubes and was rated at 24 watts. The LM 508 which I previously owned utilized 805 tubes and rated at 48 watts.
Users from other forums who had the 518, preferred the 508 which has better control and slam over the 24 watt unit.
Wig
Users from other forums who had the 518, preferred the 508 which has better control and slam over the 24 watt unit.
Wig