Pro-ject tube box DS sounds mushy in the middle

I have a stock Tube Box DS which I bought used and the mid-range seems muted and the highs not very crisp. Classical records sound pretty good, opera as well. Pop and rock just seem lifeless. Would replacement tubes make much difference. I prefer brighter sound. Phono not nearly as bright as digital feeds from CD. Using good DAC with optical input.
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Possibly. Did you lose a quality that you had with another phono amp? Or is this your first in comparison with your digital source? You could try brighter tubes like Electro Harmonix. What is your cartridge? MC settings could be incorrect.
Thanks. I discovered the problem, the F/V jumpers were installed which killed serious dynamic range. I removed them and the subsonic jumpers as well and it's like a cloud lifted. Great high end, punchy bass and bright mids.. 
Dumb operator-me.

Using Ortofon 2M Black so no jumpers needed except for 40db.

Good. RTFM. ;-)