Mccormack DNA-1 describe the sound characteristics

Several years ago, after buying a DNA-1 from 1st owner, I toyed with upgrading or changing to another amp. The amp didn't seem to fit well with my system, but after talking with others online and with Steve Mc., I went with gold+ upgrades. What a good move! I must be brilliant.
The soundstage deepened significantly, each instrument more distinct, and there was no 'brightness' to be reckoned with in the mid-high range. Bass was fuller without 'boominess'. The overall result was beyond my expectations.
I use the DNA-1 in the warmer months with a tubed pre (Gill Audio Alana Mk III), and trade out with a ARS Filharmonia integrated (tubed Spanish made heater) in the winter. Both do well in the system, but the MaC definitly has more horsepower and draws deeper into the music than the 50w integrated.
Think about an upgrade, and as mentioned above, speak with Steve; he is quite approachable and not at all 'hard-sell'.

System: Esoteric DV-50s modded
Merlin VSM-Mxe with super Bam
Audience 24au IC's, Supra Sword Speaker Cabling

I have morrow interconnects which I suspected originally, but now have well over 250hrs. on them. Can they still be bright and not allow full music through?

I used a TAD-150 signature and stock DNA 1 for 4-5 years. I found the combination to be a great match, very revealing of upstream changes, new cables, etc. If anything, I'd describe the sound as full and rich, and perhaps not as resolving as other systems that I've heard. I never found that combination at all fatiguing, though.

I agree with the other posters that you may want to focus on other parts of the chain initially to address the brightness that you're hearing.

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I reversed the speaker wires on the amp side placing the positive to the negative labeled connection. I listened to one song and found the sound to have a little more bass and slightly fuller.. with a little less brightness. Could the amp be wired incorrectly? The TAD isn't phase inverting like some Cj pres... All other interconnect connections are as labeled. The other course thing about the amp,the left side heat sinks are black while the right side has a purplish hue. I would think both side should genrate similar heat and would be colored in the same manner??

"I would think both side should generate similar heat and would be colored in the same manner??"

You would think so but maybe the previous owner wasn't running the amp equally in both channels at high levels for years. Or the heat sinks were from different batches.
Put a test CD (ie. stereophile, etc.) in and using a multimeter on the amp's speaker terminals measure if both channels are the same. Check DC offset while you're there.

You can't evaluate the sound using FM tuner as a source.

How do the Alons sound with your Luxman receiver using CDs? If still bad, don't rule out your speakers and their positioning in the room.