Hey everyone my first time on the forum, I just received my Stellar M700 amps and matching preamp. Connecting it to magnepans 1.7s speakers. My initial impressions, they don’t come close to what I already own, CJ MF2300 amp and CJ PV12 tube preamp. I wanted the M700’s for the power hungry Maggie’s. I wanted to return them, however PS Audio advised me to burn them in, which i’m doing as I type. At least 200 hours. Anyone out has had the same experience and has the burn in made a drastic difference in the sound quality?
Hi milesperhour and welcome
They do improve over time, but I wouldn’t say drastic
Could you describe what exactly you don’t like about the sound?
Yes Class D amps do improve with break-in and for most 150-200 hours is enough. Also they need to be left on all the time to sound their best. Not in standby mode but fully on.
Well the instruments sounded flat it was missing the full rich sound my CJ amp and preamp has. The imaging was better on the m700’s , I think due to it being mono amps. I was interested in the 700’s for more power to the Maggie’s but not at the expense of sound quality. I will hook the 700’s back up in a week and retry again and post my results. thanks
See if you can hook them up playing something for a week or so before you put them back with the Maggies. Any load will do the trick.
You may also be missing the effect of the particular voicing of your old preamp - might’ve worth trying the new monoblocks withe your old preamp
Presumably ps audio would let you return just the preamp and keep the m700s if that combo works for you?
I have them hooked up to a source an small speakers. They are playing now for 48 hours, I will put about 224 hours or more , then hook them back up to my maggie’s. I will try swapping the CJ preamp as well. Thanks
I didn’t hear any noticeable difference after “burn-in”. I also leave the amps in Standby mode (rear panel power switch is always on). I like their sound either way. I’m running Series 1 901’s so 350W@8Ω is enough for the 18dB of boost need above 10kHz and below 100Hz.
I have a Conrad Johnson PV10 preamp and MV-55 tube power amp. I also have the SGCD mated with M700 monoblocks, and switch back and forth between the systems. And yes, I fully understand what you are hearing. The M700’s will definitely get smoother in the midrange than what you are currently hearing (and they do need to be left on, as others have already mentioned). However, the midrange may not get to the level of smoothness you have come to expect with the CJ tube preamp (though bass clarity, depth and power should be much better with the PS Audio preamp). PS Audio’s M1200 monoblocks (a future product), from what has been mentioned, will have a tube input stage to go along with a solid state output stage, and with even more power than the M700, which might be a better fit for your situation, or the truly wonderful PS Audio BHK 250 Power Amp (tube input solid stage & solid state output). (the CJ MF2300 & PS Audio BHK were designed by the same person). A PS Audio BHK preamp also would ideally be mated to the BHK 250 power amp. I have tried listening with the CJ tube pre and solid state M700 monoblocks together, but actually prefer to go with either all CJ tube pre and power or all PS Audio solid state pre and power amps, depending on what music I am listening to.
Thanks adifferentpaul , I think that’s good advice, I appreciate it👍🏼
Well I wanted to report back to everyone after burning in my stellar M700 amps and preamp. I burned them in for 215 hours. The change is dramatic, soundstage excellent, imagery excellent, punchy bass, and midrange warmed up a lot. I will be keeping them. Thanks for all your advice
They will still get a bit better over the next couple of hundred hours and then that will be about it. That’s based on my experience with three different Class D technologies based amps
Glad to hear that
They will also sound best if you leave them powered on all the time.
Awesome. Yes, sorry that the M700s take so much burn in time. But, it’s worth the time spent.
We’ve been playing with their upcoming big brothers, the mighty M1200 mono blocks due out this January and they too take a good deal of burn in time. And they have a vacuum tube input stage that benefits from the on time as well.
Would leaving them completely turned on shorten the life span? I was considering just turning them on and letting them warm up 30 minutes or so before listening to music.
Also thanks Paul for your response,it’s great getting feedback from the CEO , your whole company has made me feel very appreciated (like family lol) thanks again. I will be a repeat customer for sure. Ps, I’d like to buy one of those audiophile hats if find one.
Leaving them on will not shorten their lifespan. Arguably, warming and cooling cycles can cause a bit more wear.
I turn everything off when I am not listening.
Leaving it all on will increase lifespan, in my opinion/experience. If anything will fail, it will nearly always occur early in its life. However, the repeated shock of inrush current and hot/cold/hot cycles will shorten component life increasing failures.
M700 consumes something like 7w in standby and all of 13w fully on. Don’t quote me but it’s close , very low.
Longest life and best sound: keep it all on (standby for tubes)
Shortest life and less good sound: turn it off between sessions
If I’m going to be away for more than a day or 3 I do shutdown and unplug power feed, just to be safe
I’m old-school, so I leave all of my audio gear on all the time, and have done so for over 33 years without any issues. I’d leave the M700 monos on all the time since Class D is efficient. Paul is right about the 200 hours. Mine were a little rough right out of the box, yet sounded better than what they replaced, but they most definitely got better as they burned in.
Good choice (on keeping the SGCD & M700). Do you have any updates on the sonic differences you notice between the PS Audio and Conrad Johnson?