The P-5 has a moderate specified gain of 12 db balanced and 9 db single-ended. Those would be the gains it would provide with its volume control at max, and those numbers correspond to an output voltage that is about 4 times as great as the input voltage for the balanced case, and about 2.8 times as great for the single-ended case.
Most digital sources provide maximum outputs in the area of 2 to 3 volts single-ended, and twice that balanced. It isn’t clear whether the LSA’s "greater than or equal to 2 volt" specified overload point applies to its single-ended inputs or its balanced input or both. So to be certain that an overload condition won’t arise let’s say that the P-5’s volume control should be set no higher than what would cause a 6 volt input to result in a 2 volt output. That corresponds to an overall gain of -9.5 db. To be completely safe under all conditions you would therefore want to set the volume control to provide an attenuation of 9.5 + 12 = 21.5 db, or more.
Roughly speaking, rotary volume controls will typically provide that amount of attenuation in the area of the 12 o’clock position.
If you are using a vinyl source, or if your interconnections are single-ended, you could probably go somewhat higher than that position. And given the conservative assumptions I stated above, perhaps you could do that for many digital sources as well.
Overloading of the LSA’s input would result in obvious distortion, btw. While if you go too low on the P-5’s volume control, noise levels and/or sonics might be compromised to some degree. But I would expect that there would be a fairly wide range of settings of the P-5’s volume control within which the exact setting would not be particularly critical.
Good luck. Regards,