Preamp with Tone Control Recommendations ....

Any of those units would be good choices and all have the same EQ capability. Had the C2300 and currently use a C50. C50 warms up faster and is a bit better with electronic instruments, but is somewhat clinical in comparison on acoustic material (something I generally prefer). C2500 is a C2300 with a DAC - don't know if that would make a difference for you.

I'm not a fan of separate EQs in the home environment; extra cables = too much noise potential. Internal tone controls are inherently better shielded. Good luck & happy listening!

Not many options anymore! Looks like an EQ is the only way to go!

Triode Corporation TRX-1 Tube Pre-amp comes with tone controls.

The great thing is that these tone controls can be bypassed too; using the remote.