EHOEHN,
I had an older version 555 mkII and a GFP-565 pre. I found the sound to be very sterile and hard edged. I sent it to musical concepts for their basic mod. I can't remember the exact cost but I think it was around $300.00. I have found the sound to be much smoother and the soundstage is much wider and deeper. I have had the unit for 6 years since the mod and have had no problems. Good luck
I had an older version 555 mkII and a GFP-565 pre. I found the sound to be very sterile and hard edged. I sent it to musical concepts for their basic mod. I can't remember the exact cost but I think it was around $300.00. I have found the sound to be much smoother and the soundstage is much wider and deeper. I have had the unit for 6 years since the mod and have had no problems. Good luck