[west]

I built a typical phono amp with 3 12AX7s, the last tube a cathode follower
(low impedance). It has plenty of gain (70db) and can easily drive any amp
directly. I like using a 100k step resistor volume control instead of a line
amp.
My problem is that when I use any of my tube amps, the sound has limited
bandwidth. A SS amp does not exhibit this problem, if fact the SS sound is
rather impressive to me (for silicone).
With my limited know-how, I'm swagging that an impedance mismatch is the
culprit.
If my contention is correct, is there a simple cure besides using a line
amp? Perhaps some kind of buffer is called for. All comments welcomed and
thank you.

Cordially,
west