Thats a tough question. At low volume the bass is still there and the highs are pretty sweet and this is driving the Pi 4's. So using the amp within it's sweet spot it has a nice balance; good vocals, not shrill. Picking up the volume it starts to fragment and the highs become pronounced and a little mettallic and the mids collapse somewhat. So I would say the response is balanced throughout the frequency range at reasonable levels. Comparing it too my EL 84 PP amp it sounds a little thin and weaker in the midrange, with less power through the lows . However the highs are more defined while not becoming etched and harsh until you crank the volume. Trying to compare SET's with anything else is just about moot since every SET i have heard sounds very different from all the other SET's and from all other amps of any flavor. So; my opinion, I would say it would make a nice HF tweeter amp unless you are used to exotic tube amps. Hope this is helpfull,J.R.