Almost always the source for me. This staying up late thing happens anytime I make a major upgrade to my table, arm or cartridge. It also happened when I upgraded from a Genki to an Ikemi CD player.
Although I have really enjoyed other component upgrades, the only non-source changes that have lead to sleep deprivation are phono stage upgrades (first from a Kolektor up to a Dynavector P75, then up to a Linn Linto).
Although I have really enjoyed other component upgrades, the only non-source changes that have lead to sleep deprivation are phono stage upgrades (first from a Kolektor up to a Dynavector P75, then up to a Linn Linto).