I spent several hours comparing the USA JP IIC+Red amplifier before the update (A) and after the update (B). Here are my observations. At the beginning I noticed that the visible default values have changed: Supply Sag from 1.50 (A) -> 1.10 (B) and Grid Bias from 60% (A) -> 58.3 (B). Initially, I liked the amplifier better after the update (B). Then in the old amplifier (A) I changed the Suppy Sag values to 1.10 and Grid Bias to 58.3%. At this point, all values of both amplifiers were the same. Now I liked the old amplifier (A) more. It was clearer. The new amplifier (B) was a bit fuzzy and had more bass, as if I had put a blanket over the speaker. Then in the new amplifier (B) I reduced the overdrive saturation from 8.3 to 7.7 and that was what I needed. The sound came alive and became clear and pleasant. Then, in the old amplifier (A), I also reduced the overdrive saturation from 8.3 to 7.7 so that both amplifiers had the same settings. The sound in the old amplifier (A) has improved, but not enough to be better than in the new amplifier (B). The sound in the new amplifier (B) was better, more pleasant, sweeter, nicely blurred without being harsh. There was more of a pleasant agent that gave it that sweetness. The sound was liquid. The old amplifier (A) was more raw, had a noticeable roughness, the bass was harder and less pleasant. If you notice that the sound is muffled or less clear, try reducing the saturation. This should help. At first I had mixed feelings about this update, but in the end I think it's really, very good.