I will also add this to support nonoise's recommendation of possible checking out Finale Audio. I also swap in their 7189 MK2 integrated (22 wpc) EL 84M or 7189 tubes to drive the Argos. Different sound obviously then the 845 based LM 518IA, but again easily drive the Argos. Frank at Finale Audio is also very easy to communicate with and easy to deal with