ECO's all change the sound in some way, generally not for the better. I find them acceptable, if only used on the low pass side at 500hz and under, generally they take away midrange bloom and transparency. But I suppose you know all that. I myself use an old Mark Levinson ( the man, not Madrigal) on Maggie Basspannels cut at 500hz to good effect. The unit is over 15 years old and never gave me any trouble.
The FM Accoustic, fiendishly expensive,is the best unit I have ever heard, veiling the midrange only very, very slightly, with a slight pinch of grain in the highs. It is very well built, expensive parts, TAS raved about it once, don't remember which issue. I tried Sony, various Brits stuff, ARC's, found them all unacceptable. Unfortunatedly, I have no experience with the Krells, neither with the Accuphases.
Sorry, so I can't really be of help. Hope there is more coming on this thread, because the topic interests me too.
Good luck!
The FM Accoustic, fiendishly expensive,is the best unit I have ever heard, veiling the midrange only very, very slightly, with a slight pinch of grain in the highs. It is very well built, expensive parts, TAS raved about it once, don't remember which issue. I tried Sony, various Brits stuff, ARC's, found them all unacceptable. Unfortunatedly, I have no experience with the Krells, neither with the Accuphases.
Sorry, so I can't really be of help. Hope there is more coming on this thread, because the topic interests me too.
Good luck!