Think back to the time when your system operated exactly as you think it should. Then think of the changes you made and the effect you noticed after you made that change.
I looked at you old thread on this subject. If I understand correctly you have had ALL of the stuff working in your system, amp, pre-amp, speakers and source before you encountered this problem and it only occurred since you started rolling tubes or, perhaps, something else?
Now if you had said that you noticed the 'loss of gain' after you changed the speakers, or the amp, the answer would be easy - that is the speakers were less efficient or the amp had lower input sensitivity both of which would have required some additional rotation in the volume control.
Tube type can affect gain, for an easy example a 12AT is low gain, the 12AU is higher, and the 12AX is highest of the three and the difference is substantial. They are 9 pin tubes, they are of the same size, superficially look the same and can be used (sometimes intentionally) interchangably. I've seen cases where a unit reqired several differing ones and they were put into the wrong sockets causing an unwanted increase in gain or the obverse . So you want to be absolutely sure you are using the correct tube type in the correct position.
If either of these three posibilities have been addressed and are not the problem you might assume that as the gain issue affects both channels you want to mainly look at things that work for both channels at the same time, like rectifiers, power supplies, etc. If you have one handy you might put in a different amp and see if the problem changes. BTW since you have this same problem with both a PV10 and a PV 12, other than causing a problem by using incorrect or misplaced tubes, it is likely the problem occurs downstream.
Now the GOOD NEWS! Having to rotate your attenuator to a 11 to 1 oclock position to get proper sound levels IS NOT a bad thing. In fact in many, if not most preamps, the attenuator (volume control) is operating in its most linear position there.
I don't know if this makes any sense to you but its all I can think of with the information furnished.
I looked at you old thread on this subject. If I understand correctly you have had ALL of the stuff working in your system, amp, pre-amp, speakers and source before you encountered this problem and it only occurred since you started rolling tubes or, perhaps, something else?
Now if you had said that you noticed the 'loss of gain' after you changed the speakers, or the amp, the answer would be easy - that is the speakers were less efficient or the amp had lower input sensitivity both of which would have required some additional rotation in the volume control.
Tube type can affect gain, for an easy example a 12AT is low gain, the 12AU is higher, and the 12AX is highest of the three and the difference is substantial. They are 9 pin tubes, they are of the same size, superficially look the same and can be used (sometimes intentionally) interchangably. I've seen cases where a unit reqired several differing ones and they were put into the wrong sockets causing an unwanted increase in gain or the obverse . So you want to be absolutely sure you are using the correct tube type in the correct position.
If either of these three posibilities have been addressed and are not the problem you might assume that as the gain issue affects both channels you want to mainly look at things that work for both channels at the same time, like rectifiers, power supplies, etc. If you have one handy you might put in a different amp and see if the problem changes. BTW since you have this same problem with both a PV10 and a PV 12, other than causing a problem by using incorrect or misplaced tubes, it is likely the problem occurs downstream.
Now the GOOD NEWS! Having to rotate your attenuator to a 11 to 1 oclock position to get proper sound levels IS NOT a bad thing. In fact in many, if not most preamps, the attenuator (volume control) is operating in its most linear position there.
I don't know if this makes any sense to you but its all I can think of with the information furnished.