Had a similar complaint about limited volume control range on my gear...though perhaps not as extreme as what you report, Pix. Almarg suggested attenuators. I went with Harrison Labs -12dB attenuators purchased from Parts Express. They were around half the cost of the Rothwells. I put them on the end of the IC going into the preamp from my CDP and got another set for the IC coming from my DAC...again, using them right at the preamp. These gave more volume control range. I did not hear any obvious reduction in frequency response. Could you experiment with different insertion points for your attenuators?
Good impedance match for Precision Fidelity C-7AR
When using my PF preamp with either my tube or SS amps, I have only two volume settings I can use, low or too loud, at between 8 o'clock to 9 o'clock on the volume pot. At the higher of the two volume settings, the preamp seems as if it is outputting full voltage. The input impedance on the tube amp is 100Kohm, and the main output impedance on the PF is 600Ohm - 7Kohm. Is this a classic case of impedance mismatching? Would it be worthwhile to see if there is a problem in the PF unit, or, should I check into locating a better matching amplifier?