Every little upgrade adds up, but the biggest jump is simply having enough power for full-size headphones. As Mad said, it’s easy to add an external amp later if you want... but you may not feel like you need to. The upgraded power supply only affects the active speaker outputs, no change for the headphone outputs. Hi x1o8x, That sounds like it might be a defect, I’d recommend reaching out to Sennheiser support: https://service.sennheiserusa.com/ Exactly, tube amps can vary in presentation of soundstage just as much as any solid state amp. My first good amp was a tube amp (still have it!), and the ability to separate instruments and place them in a soundstage was FAR better and bigger than the pocket SS amps and phone amps I used before.