I think so. I have a UR22 which I’ve owned for 3-4 years, and recently borrowed a newer UR22 mkII from a friend. The first thing I noticed after I plugged it in was that the phones output volume is significantly lower on the mkII. I haven’t measured the exact difference, but it’s quite a bit… Definitely more than just a couple of dB. I usually have the knob turned up to around 10 o’clock or so, but on the mkII I have to turn it up to 2 o’clock to get decent volume.