4-ohm setting with 8 ohm speakers


I have the Nightingale CTR.2 open baffle speakers. The manufacturer claims that "the Concentus CTR-02's speakers and crossover are designed and assembled on the acoustic screen following a scheme meant to guarantee that the impedance stays linear as the frequency changes."

However, with every amplifier used with these speakers, a 4-ohm setting sounds more natural and relaxed. Now I am listening them with the Hans Labs KT-88 power amplifier. With the 8-ohm setting, the sound is more tight, bland and stringent, it sounds more like a mid-level SS amplifier. I am wondering how this can be explained from technical point of view?
transl
A lot of amps like to see a higher impedance on their outputs, and do sound better this way. One tube amp company was using only a 4 ohm tap at their outputs for this reason.

The 4 ohm tap was recommended, the 4 ohm tap sounds better, I use the 4 ohm tap, case closed.
The output tubes or transistors will see less of a load using the 4 ohm tap, perhaps maybe half of what it would using the 8 ohm tap. That is the purpose of output transformers (impedance matching), and autoformers.
Hifihvn (Answers | This Thread)

I agree with this. As I agree with Hifihvn. Another good explanation is offered by Roger Modjeski who recommends trying "light loading"his the RM-10 MkII amps. There is a pretty clear explanation as to why in the owners manual. Lower distortion and longer tube life being a couple benefits, at least where the RM-10 MkII is concerned.