Definitely look at some other part of your system, and/or incoming power.
Given what you have on hand now, I'd say look for better speakers.... Possibly cabling too. or try another DAC. Additionally, tubes in the Dodd pre.
One of those areas or maybe two should fix the issue pretty much. The room is always a main part too.
Getting another amp, without improving upon the level of speakerage you have now seems like a more sideways step to me.
If you've got to go grab an amp that's better sounding than the Odyssey, either add a pair of Dodd mono block EL34 amps, or get yourself a Butler TDB 2250.
the Dodd mono blocks are sweeter sounding, using only a TDBH 5150 (150wpc), not the 250wpc like the TDB 2250, the Butler sounds better to me and has more control and better bass.... the 250wpc version ought to be way better, and allow you to throw some $$$ towards your speakers as it sells new for $3K.
before pulling the trigger on anything, like all have said here, the brightness probably isn't the amps fault.
Got dedicated ckts? Checked for ground loops? use a power cond? how's that cabling situation, pc's & ic's? What are the speakers sitting on and how are they isolated? Got a good rack?
it all adds up.
Good luck.