I find that every component has a sonic signature. Film and foil caps are the most neutral, with few exceptions. I find the most neutral of the sanely priced caps to be MIT Multicap styrene film and tin foil.
I haven't used Jantzen caps, so I can't offer specific comment, but I can tell you that every electrolytic you replace has the potential to dramatically change the sound. At first, the sound may appear to be less bright, but that is probably because electrolytics tend to introduce lots and lots of nasty high frequency distortions, which can be confused with brightness. So replacing the electrolytics is simply removing high frequency distortion.
Try some unprocessed female vocals. See which speaker sounds the most like the women in your life. Then live with the sound for a month, and try again. You may be surprised.
I haven't used Jantzen caps, so I can't offer specific comment, but I can tell you that every electrolytic you replace has the potential to dramatically change the sound. At first, the sound may appear to be less bright, but that is probably because electrolytics tend to introduce lots and lots of nasty high frequency distortions, which can be confused with brightness. So replacing the electrolytics is simply removing high frequency distortion.
Try some unprocessed female vocals. See which speaker sounds the most like the women in your life. Then live with the sound for a month, and try again. You may be surprised.