Recent upgrade to Cronus Magnum

A few weeks ago, my system consisted of the following components ...
Apple TV >> Naim Unitiqute (v1) >> Harbeth P3esr

While I liked the overall sound, I wanted to move up the chain and try something different. I felt the Unitiqute was a little underpowered. So when an Audio Rogue Cronus Magnum came up for sale (local craigslist), I jumped at the chance and bought it. I had a Cambridge Audio Azure 851D stored in my close, which I added to the chain. So now my system looks like this...
Node 2i >> CA Azure 851D >> Cronus Mangum >> Harbeth P3ers

When I first made the change, I was quite impressed with the increased loudness and a wider soundstage. However, I realized that, unlike the Naim, I was getting listener fatigue. There was a certain harshness (like metallic sound) to the vocals, especially female vocalists. Also, I was expecting some tube magic, which frankly is just not there. The Cronus Mangum sounds much closer to a solid state. Yesterday I put the Naim back in the system and much to my surprise the little box is keeping pace with the much more powerful Cronus Magnum. Yes, it doesn't play as loud and the soundstage is not as wide, but the sound is so much more refined, smooth and balanced. I'm wondering if I made a mistake. So before I make further changes, maybe the good folks at Audiogon can provide some relief.

What do you think is the weak link in my system? Should I keep the Cronus Magnum and try a more musical, refined DAC? If yes, what do you guys suggest (prefer used, below $2000)? Or do I ditch the Cronus and go for a more tube-like sound (Primaluna, Rogers, vintage ARC, etc)? The little voice inside me is telling me to sell the Cronus and move up the Naim integrated chain (e.g. Supernait), since I really liked the Unitiqute's refinement and balance. But then again, what if it's not the amp (Cronus) but the DAC (CA Azure 851D) that's the likely culprit here? Should I change the DAC first? Or maybe try rolling different (smoother?) tubes?

As you can see, I'm mighty confused and can use some pointers. So many variables ... aargh!!!!
The cronus is known for being non tubey . Its recommended to not adjust bias often.
I had been traveling quite a bit in February so didn't get a chance to try out different tubes. Finally got around to ordering new tubes from Brent Jesse as per @avanti1960 's suggestions. Was advised to get the Amperex (1960) for the center/preamp as suggested on this forum. But Brent suggested that I go with Amperex for the AX7s as well. He also advised me to let them burn in for at least 48 hours before doing any critical listening.

So what's the verdict after changing 3 tubes? All I can say is, wow! The sonic improvements are not subtle by any means. I'm getting much more detail than before without any harshness, all in a very polished and smooth package. Better tonality, more separation and air between instruments. Much wider and deeper soundstage. Vocals sound more natural than before.

But the biggest improvement by far is the quality of bass. I never thought I could get the P3esr's to produce such satisfying base. It doesn't go much deep but whatever I'm getting is tight and very palpable. I was thinking of adding a subwoofer, but honestly at this point I'm not sure I need it. Everything sounds so balanced, don't want to ruin it.

Another improvement I noticed is that I'm getting more details and bass at low-to-moderate volume. Before, I had to crank it up to 11'o clock to get the details and bass. After the switch, everything sounds pretty good even at 9'o clock position on the dial.

Thanks everyone for the amazing advise. I'm pretty happy with the music this system is producing. I'll probably swap the remaining AU7s in a few months, and maybe get a copper-based speaker wire to see if I can eke out even more improvements.
How much did the Amperex (1960) Tubes cost?