Not ENOUGH GAIN

Yep, Onhwy61 and others are right on.

I think you might look at in a different manner though. A pre-amplifier's amplifying section comes after the volume control an is always seen by the amp at its full output (gain). The volume control is an attenuator between your source and the pre-amp's amplifier section. When fully rotated the VC is allowing the gain of the source to pass to the pre-amp at full value. When the VC is rotated counter-wise it reduces the gain from the source, it does not reduce the gain from the pre-amp itself, nothing does - it is a constant.

Make sense to you? Take our word for it, you're in hog heaven.

Clio, I'm sure you are right, but I don't understand the value of such an arrangement unless you are using an attenuator with fixed impedance values so the impedance value seen by the amp is constant. Is that not why most amplifying sections come after the attenuator?

I guess in hog heaven an attenuator with fixed impedance values coming after the preamp' amplifying section could be optimum as it would not only control volume it would lower the pre-amps noise level as seen by the amp something of much value and could also make interface with various amp input sensitivity levels more efficiently. No more problem with high gain pre-amps and high sensitivity amp inputs, a common real problem. Keeps Rothwell busy I think.

Do you know why they actually use such a configuration? Do you know why they don't?

I think the best gain control on an amp is no gain control. It is convienient perhaps when your pre-amp is noisy or has too much gain to give you full use of the VC on your pre-amp, but you don't really need the minor degredation its use can create. Turn it to maximum and use the pre-amp VC. Now if you have a noisy gain stage in the pre-amp it can help reduce the noise - for me no noise is a bit better than minor degredation by the addition of a second attenuator.