I actually have a PM Ki Ruby playing a pair of Revel F208 and had a MF M6si for 3-4 years playing the same speakers and a pair of Monitor Audio Gx300 before them.
I upgraded the M6si to a Pass Labs x250.5 and then I moved it for a second system so I needed a new amplifier and got the PM Ki Ruby.
I need to say both are excelent, the most important difference is the presence of a very good DAC in the M6si.
I never did a direct comparisson but I remember clearly the sound signature of the M6si.
The Marantz has more bass impact and a little warmer sound. The M6si is flatter with more resolution and shows more mids presence. Again the soundstage o the Ruby is three dimensional and shows a lot of depth and is the first thing you will note. Both are very engaging not analytical in anyway.
The cons of the Ruby I would only quote for a little hi frequency sparkle that bothers me in some recordings. The M6si is less engaging but easy on long listening sessions.
I would like to say that a I struggle with the M6si until I discover the impact of speaker cable on it. I am not a snake oil head but in this amplifier the speaker cable has a lot of contribution for the results.
If I could choose now maybe I would prefer the M6si over the PM Ki Ruby but here in Brazil we have limited availability of eletronics and sometimes the prices got a lot higher than the international prices.
Another point is the aesthetics. The PM Ki Ruby is a wonderful piece of equipment and gives a lot of proud of ownership.
I upgraded the M6si to a Pass Labs x250.5 and then I moved it for a second system so I needed a new amplifier and got the PM Ki Ruby.
I need to say both are excelent, the most important difference is the presence of a very good DAC in the M6si.
I never did a direct comparisson but I remember clearly the sound signature of the M6si.
The Marantz has more bass impact and a little warmer sound. The M6si is flatter with more resolution and shows more mids presence. Again the soundstage o the Ruby is three dimensional and shows a lot of depth and is the first thing you will note. Both are very engaging not analytical in anyway.
The cons of the Ruby I would only quote for a little hi frequency sparkle that bothers me in some recordings. The M6si is less engaging but easy on long listening sessions.
I would like to say that a I struggle with the M6si until I discover the impact of speaker cable on it. I am not a snake oil head but in this amplifier the speaker cable has a lot of contribution for the results.
If I could choose now maybe I would prefer the M6si over the PM Ki Ruby but here in Brazil we have limited availability of eletronics and sometimes the prices got a lot higher than the international prices.
Another point is the aesthetics. The PM Ki Ruby is a wonderful piece of equipment and gives a lot of proud of ownership.