Hi, my amp is an Audia flight strumento no.4 mk2, and it drives the speakers very well. I’m now considering upgrading the preamp. I’m fine with either a tube or a solid state. Since the amp’s input impedance is 7.5 kohms, I’m searching for a preamp with an output impedance of < 200-300 ohms, lesser the better. Price < 20 k, preferably less than 15 k (if used). I’ve narrowed it down to these. Unfortunately, despite the fact that audio research is highly regarded, their performance impedance is too high for my preamp. Any observations, experiences, or ideas on these topics will be greatly appreciated.