I had the same experience. In my case I was running a McIntosh solid state amp with the auto transformers. I was using the 8 ohm taps for my GE Triton Reference speakers. On a whim I tried the 4 ohm taps, and Holy smokes, what a huge diffference for the
Trying different output impedance taps with tube amps
My Antique Sound Lab Tulip 2A3 SET amp has 4, 8 and 16 ohm taps. I had been running the 8 ohm taps, and had a friend over to listen. He suggested the 4 ohm taps might be a better match for my speakers (Audio Note AN-Es). He was right, and it made a really nice improvement.
If you have multiple taps on your amp(s) and have never tried the other ones, or haven't for a while, it's worth a shot. Even if you are using the recommended or “right” ones for your speakers, you might be surprised.
If you have multiple taps on your amp(s) and have never tried the other ones, or haven't for a while, it's worth a shot. Even if you are using the recommended or “right” ones for your speakers, you might be surprised.