I think they are both equally important. The most important aspect of a tube amp(in my experience) is the transformers. It is by far, the most expensive functional part of a tube amp. This is what separates Jolida from companies like Air Tight. Yeah, they both use the same tube type(EL34, and same tube once you retube the Jolida), but there is something that prevents you from attaining that same level of sound for the two. Transformers are as different as anything else in the amp. If we would allow that interconnects have a major effect on sound, then we also have to give transformers their due. They have several orders of magnitude more length than a 1 meter interconnect. Like most cables, most use different wire, and different construction. We also have to consider the circuit design, parts quality, etc.(things we NEVER mention with tube amps). That being said, we take tubes seriously because it is the one area of the amp we can control. Like different brands of gasoline yielding different performance in our cars(we can't change engines). We get different sounds from different tubes. Garfish, if you need to maintain the level of bass you are accustomed to, you need to look at amps with the larger tubes(6550/KT88/KT90). But, please go out and listen to an EL34 amp. There is a tube magic in many of them that is quite addictive. You may find yourself with two setups.