I still don't quite understand your experience with NAD inbuilt amp. I have medium efficiency speakers and sub and I can drive it louder than my ears can handle with metal and pop. With classical and soundtrack there isn't much reserve left after Dirac but it is just enough for live levels.
Also, Fosis can't have (and I really mean can't, not an opinion) more detail than nCore. Having to adjust eq after changing an amp is not something that should be a thing.
I mean I'm happy it works for you but something is a bit odd here.
The M10 V1 had some issues which I took up with NAD tech support. Eventually after I complained hard enough my thoughts were confirmed that the way they implemented the M10 gain was borked. When the V2 was implemented NAD made a big deal of "
updated gain algorithms" whatever that meant, while declaring there was nothing at all wrong with the V1. Long story short there was insufficient signal to wake the sub at normal listening levels and the volume had to be wound up to get a normal listening experience from my speakers. So its not the amps really, its the implementation in the M10 that was later made better, noting that Levinsons new company Daniel Hertz is using nCore amplification in their products.
This was an issue noted by many, the support forum was full of similar observations to mine for NAD/BlueSound products at the time. NAD told me it wouldn't be fixed in the M10 V1 suggesting it was hardware configuration rather than software settings.
The M10 has the option for outboard amplification and I had been looking at the NAD or VTV Eigentacht amps as options. Enter the Fosi V3 which when tested sits right alongside the NAD Eigentacht powered devices in measured performance and at a fraction of the cost, for example around aud $3500 for the C298 which was under consideration. It made perfect sense to me to check it out. For sure the FOSI V3 is not as powerful as the C298 but that's academic for my use case. Lets agree power is about the same as the onboard nCore amps for the sake of the discussion.
On sound quality, M10 has always been very good, especially with Dirac. It was the least expensive way to get on board and obviously the BLuOS environment is just great so no problem there. Now though it requires a different Dirac curve in the same room so something must have changed I guess. I'm using the same calibration sequence for recording tones, same mic and stand. Different DL version though. The top end needed to be wound back compared to previously and the standard NAD curve was used in the end which really chops the high end compared to just the Harmon target previously. I cannot explain why this is, but thats what happened.
The Fosi amps are connected to the line out at the 31db sensitivity level so there is a different experience at the volume control now, but that's not the whole story. The speakers are revealing things not heard before or in a way not heard before from music that's been listened to a lot. Particularly acoustic music where the scrapes on guitar strings hang in the air and so on. If you lived nearby I'd invite you to audition yourself.
The speakers are PSB Imagine Minis on factory wall mounts high up on the wall. They are renowned for being able to resolve a lot of detail and they do. Each amplifier iteration that's been attached to these speakers reveals more as I've plugged in better equipment. Now I have the BluOS experience with Dirac and the whole thing sounds better than before for not much money on the amp update and at least a $3000 saving on plausible alternatives.
So are the nCore amps OK, sure despite the issues in the M10 V1 implementation noted in Amir's review. I think that's the point, the implementation in the M10 has not really let them shine like they should. AMIR notes:
"Performance of the NAD M10 is generally acceptable especially for a multifunction device where we see a lot of fails. Alas issues here and there took away my enthusiasm for it. There is no excuse for poor analog input performance in a nearly $3000 device.
Or rather high and variable noise floor."
M10 V1 ranks 86 on the SINAD chart. Not shabby but FOSI is better. Considering the FOSI amps connected outboard, what else provides so much price/performance/value for money?
