it will to many still sound better than any active preamp, with or without gain.This statement is false, on account of the word 'any'. "Some' would make it accurate.
A buffer or gain stage added to a passive with good impedance and gain match can only add distortions/colourations.This is a common myth. The problem is that passive controls can do this too. So the trick is to figure out what works in your system- and the vast number of options is why this is so tricky.
I would have thought the least amount noise would come if the master is at or near full for loud listening, then the gain level if it is controlling the "tube gain" it’s then only increasing any noise to a minium level, as tube noise/distortion increases at the same rate as the gain will.Most active tube line stages are not built in this manner, since the volume control has to be before the active gain stage in order to prevent overload. So the noise floor of a tube line stage if well-designed will be a constant. And just so we're clear about that noise floor, on speakers of 105db, to even hear a good tube line section's noise floor, you have to put your ear as far in the midrange horn as you can just to hear it. IOW its a non-issue, as most people don't use horns (which are the only speakers that are that efficient) anyway.
Sure there is. Gain means an active circuit. And all active circuits add noise, distortion, phase and frequency distortions. If you don’t need the gain from the preamp, you can avoid these problems by eliminating the preamp.There are four functions that any line section/preamp should be able to do, and this includes passives except for the first point below:1) add any needed gain2) control volume3) select source4) control the interconnect cable between the preamp and amp
Of these, point 4 is the least understood, even by preamp manufacturers. It is certainly misunderstood by all passive control manufacturers (unless they are in it solely for the money, and some are as we have seen earlier on this thread)! If you are wondering how a passive can have more coloration than an active, its due to point 4. This is because the interconnect cable can impose an artifact as we all know, since the cable industry is a multi-billion dollar/year industry in the US, and everyone reading these words has heard cables make a difference in their system.
But if the preamp is properly designed this does not have to be the case. BTW, this is what the balanced line system was devised to do and it is very successful if one adheres to the balanced line standards. But a properly designed single-ended line section can reduce cable interactions quite dramatically as well. **No passive** can do that!
The reason I quoted the latter post above is that most sources make no provision for cable control- and thus are subject to cable artifacts. If the manufacturers of source components had their act in gear, we would not be having this conversation!
“No preamp” is a straight wire. It will add no noise, no distortion, and in 99.9% of cases no frequency response anomalies.It is now easy to see that the above post is false. Its based on the idea that cables have no artifacts, also leaves out the effects of capacitance and the like that are inherent in cables and makes the false assumption that a volume control is somehow the same as a straight wire, which it certainly is not! As a result, you can actually have an active line section with wider bandwidth that can indeed sound better than a passive and not due to 'pleasant distortions' either (since any properly designed active line stage will have vanishingly low distortion), but instead due to the additional transparency offered by cable control. The distortions created by amplifiers are far more significant!
There is not a preamp made that has the same characterics. Thus, there is no amount of money that can be spent on a preamp that will sound better that a straight wire.