Best tube mono blocks under $15,000?

Currently running McIntosh C2300 preamp and am leaning towards running Mc275s in Mono configuration but I'm new to tubes is there anything sweeter or better out there for the money? Thanks for any input.
Just FWIW, based on the impedance curve I have seen of this speaker, the MA-1 should do just fine on it- although it may be a good idea to use a zobel network centered at about 1 KHz.

Alternatively a set of ZEROs could be employed.
Thx for all the input. Seems my amp preamp combo may be serving me well. I think I'll audition the Mc275 C2300 combo and go from there.
In the "swing for the fence" category of tube amps, consider buying a used VTL Reference level Wotan MB-1250 Reference designed to "take control of the most demanding loudspeaker load and thunder out deep bass with the authority of a mighty ruler, while at the same time handling the delicate passages with speed and nimbleness of a youthful hero...the Wotan is probably the most powerful tube amplifier in continuous production in the world high-end audio industry. An awesome demonstration of the Wotan's unsurpassed power was setup for Hi Fi '98 in Los Angeles where we used 3 pairs of Wotans in a triamped system with the Martin-Logan Statement speaker systems." (specs)

For something a little more realistic -VTL's MB-450. The MB-450(specs) has "adjustable Damping Factor feedback control"

Just in case, there is a used pair of Wotan 1250($12,000) for sale here right now and two sets of MB-450 Sigs ($4,300 & $10,000)

I'm fairly certain the $4,300 MB-450 Sigs would fulfill your every need and save you ten grand at the same time. Read the many reviews. If you feel the urge for the ultimate in high-power tube amplification, unleash the Wotan. The term "effortless" would certainly apply in your system although a larger air conditioner may be needed.