[wroman214]

  I am posting this here to verify my experience.  I recently purchased a Marantz PM-KI Ruby.  I received  it on a monday afternoon and that evening after running 3-4 hours the sound was glorious. The soundstage  was huge and the speakers disapeared. A day later and the sound was tubby and disconnected and muffled. Two days later maybe a little better. This is my 1'st digital amp. If this is break-in how long could this take to come back. The bass seems over the top.
Thanks

[Craig B]

"Digital?" If you're referring to it being a Class D amp, that's not digital, strictly speaking.

I have a pair of Class D monoblocks, and there's no question their bass can be impressive, but on mine it's never approached unrealistic levels. When I first got mine, I let them run, with input, for about 300 hours before I did any critical listening. Truth be told, they probably only needed about 200.

[Stercom]

Yeah, you are experiencing what a lot of quality amps go through when they are breaking-in. Sounds good one day but not the next. Let it play for a few hundred hours and I'm betting it will stabilize. (By the way, I don't think the Marantz PM-KI Ruby is a digital amp)

[Digi-G]

I can't speak to the Marantz unit, but my Odyssey amp did a very similar thing when I first got it.  I wasn't a believer in break-in until I experienced this first hand.  It was NOT subtle, either.  Initially it didn't have much bass, then the highs disappeared and it sounded tubby and bloated.  I truly thought the amp was faulty, but Klaus (Odyssey) laughed and assured me that was normal.

As suggested, give it a few days / weeks and it will stabilize and sound better.

[jriggy]

I got this from a manufacturer years ago... Power down for 5 hours (+/-) every 48 hours (+/-). This allows the capacitors to discharge and cycle back again, evidently helping smoothen out the performance swings during break-in.
But don’t scoff at me personally for pushing voodoo, cuz I don’t know, other than it did seem to work when in one of the wild  swings.

[Craig B]

But don’t scoff at me personally for pushing voodoo, cuz I don’t know, other than it did seem to work when in one of the wild  swings.

Makes as much sense as anything else I've read. And for me, the auditory changes are quite real.

[Big Red Machine]

Every circuit will act different. I was lucky enough with the recent class D VTV Purifi Audio 1ET400A unit I had no roller coaster ride. Have I in he past with other amps, heck ya. Don't be discouraged. It will work it's way out. You do tend to psych yourself out like the sound may change and convince you it is okay but maybe it's not. Our audio nervosa kicks in but trust the electrons to flow and after a few hundred hours, you should be settled in. It's a pain, but wait it out. I'd run it 24/7 in the backgound and check in on it here and there.

No harm cycling the power as Jason suggests, but I don't see the caps discharging any time soon. If you hit a good soundstage once, it will come back.

[richidoo]

Normal for it to change like that, especially if it sounded really good for a moment. That shows that your system is otherwise dialed in well and very transparent, so it will reveal all the the highs and lows of the break-in. Rest assured, it will sound even better than your first impression after it's fully broken in. It should smooth out a lot by 25 hours, then you'll notice gradually less and less flaws as the days and weeks go by.

https://www.marantz.com/en-us/product/amplifiers/pmkiruby

[wroman214]

Thanks for the input everybody. I have been at this hobby on and off since the 70's so I have heard this before, but not near to this extent. Now the bass has thinned and the dynamics are gone but the soundstage is starting to open up.  I am running my old Squeezebox into a stepdown box to feed the phono preamp while I find enough time to rewire a tonearm. 

[SET Man]

I got this from a manufacturer years ago... Power down for 5 hours (+/-) every 48 hours (+/-). This allows the capacitors to discharge and cycle back again, evidently helping smoothen out the performance swings during break-in.
But don’t scoff at me personally for pushing voodoo, cuz I don’t know, other than it did seem to work when in one of the wild  swings.

Hey!

     That make sense, with some off time for caps to discharge and recharge again, put it through the cycle. Nothing voodoo about that at all! Actually I've been doing that by default for years now, I turn it off when I'm not home and leave things on to break-in when I'm home.
     By the way, I remembered years ago after I finished assembling my SET amps I actually left them on overnight. They sounded horrible the first hour, so I stop listen to them and just left them on. Well, I was young and want to them to break-in fast. Luckily the next morning nothing burn or burst into flame and everything measured fine still.
     My rule of thumb personally is at least 100hrs for electronics before any serious listening. Anyway, keep us updated on the Marantz... I'm curious about the "Ruby" line.

Buddy 

[rollo]

I got this from a manufacturer years ago... Power down for 5 hours (+/-) every 48 hours (+/-). This allows the capacitors to discharge and cycle back again, evidently helping smoothen out the performance swings during break-in.
But don’t scoff at me personally for pushing voodoo, cuz I don’t know, other than it did seem to work when in one of the wild  swings.

   A good call. As Beta tester back in the day that is close to what we did. We powered down for 6 hours and used 12 hour intervals. Worked every time. My pet peeve is the Manf should break it in.

charles

[wroman214]

Well it has been 8 days and roughly 175 hrs run time and the amp is sounding much better. I still have a distinct feeling that there is some ways to go but tonality is rich but maybe a little on the plump side, not that I mind that.

[opnly bafld]

Well it has been 8 days and roughly 175 hrs run time and the amp is sounding much better. I still have a distinct feeling that there is some ways to go but tonality is rich but maybe a little on the plump side, not that I mind that.

Sometimes a different amplifier requires a repositioning of the speakers.

[rollo]

Well it has been 8 days and roughly 175 hrs run time and the amp is sounding much better. I still have a distinct feeling that there is some ways to go but tonality is rich but maybe a little on the plump side, not that I mind that.

  Getting there. IMHO 350 hours is needed for an Amp. Trannies take time.


charles

[wroman214]

I did need to change speaker's some to get better focus. I got Black widow and a new to me Stanton 881S and I can say the phono preamp is killer on the Marantz. I bought the cartridge from a seller in Japan and it is a nude diamond original. I can say I never heard such unrestricted dynamics before.

[wroman214]

 I was talking to someone a number of years ago and he indicated that your system is dialed in when the perceived sound stage is heard from an adjoining room.  Finally that is what I heard while on my laptop while sitting at the dining room table and music playing in the living room.