shahram OP
https://www.stereophile.com/images/1214PLDPIfig01.jpg
Here is a behavior graph of the Prima Luna’s output transformer, as you can see it goes into stability ringing from 10khz up and the harmonics of that can effect even further down the line.
This combined with the high impedance of the speakers in the same area can be put to question.
Because the higher the impedance of the speakers, and if you look the output transformer ringing is worse at high impedance put the two together and you have something nasty going on.
Cheers George
https://www.stereophile.com/images/1214PLDPIfig01.jpg
Here is a behavior graph of the Prima Luna’s output transformer, as you can see it goes into stability ringing from 10khz up and the harmonics of that can effect even further down the line.
This combined with the high impedance of the speakers in the same area can be put to question.
Because the higher the impedance of the speakers, and if you look the output transformer ringing is worse at high impedance put the two together and you have something nasty going on.
Cheers George