Hi Bikes,
If soundbitten's advice cannot be accomplished because of no adjustment, you might try installing a signal voltage divider at the "top" of the volume pot (where signal connects to the pot).
Might try a high quality 22k and 2.2k high quality resistor, or even 33k and 3.3k. You might lose a little high frequency response due to the capacitance of the volume control, input capacitance of the tube, and stray capacitance. The signal will drop approximately 20db, or approx. 10 to 1 thru this voltage divider network. This should allow for much more use of the volume controls.
If you don't want to drop all the inputs by approx 20db, one can install the Resistors at one input.
(I would check your sources owners manual to make sure the value resistors mentioned will be acceptable. Once in a great while, like a CD player with tube analog stage, the input Z of the pre may need to be higher. But usually no problem with the resistor values given above.)
I would be careful of any voltages inside, make sure all voltages are drained. If you feel uncomfortable doing this procedure, you might take the pre to a shop to be professionally done.
Hope this helps.
