I'm looking for good pre amp with bass & treble

If I my say instead of looking for a pre amp with good bass
and treble you should be looking at a good DAC this will give you both. you have a good amp so a simple pre amp is best the one that was designed to go with, Look at MSB Tech new DAC's are in the 10,000 range but older versions can be had from $1000 to 2000 and will make a world of difference. I had the same question 5 years ago
feel free to contact me any questions

Quad 99

I agree with the Mcintosh guys, they are excellent preamps and always have good tone controls.

Any McIntosh will have tone controls. What is your budget?

Dynaco PAS

for somewhat more money look you maybe able to find a Cello Palette,has a number of tone controls.

For around 1k, the Burson HA-160D. Its a solid performer with nice bass impact and treble.

What kind of price ?

Used McIntosh C2200

Sansui CA-3000 Preamplifier from late 70s.
Built like a tank and has the tone controls and sounds very clean.
You'll see them on Ebay