Gain and level controls on an amplifier-a good thing?

I am not using a bi-amp setup. Simply using two sets of speakers with each pair powered by a different amp. They share the same preamp. 

That is unlike most others here..

But like others here, I have a separate 2-channel setup from my AV setup, so we still have a lot in common!

Does anyone bi-amp anymore? Maybe that is a bit off topic but an interesting one when it comes to gain control...in theory one would have a true treble and bass control through gain settings, right?

Since two-channel means two speakers 😀, very few of those in this forum - er, site - have ever wanted for gain control. So as fuzztone states, few folks on this site have a use case.

For those of us who utilize four speakers (because the room is of the size that requires it), gain settings are a must. 

For reasons just stated (minimal amount of use case) many mfg do not include a gain knob. IMHO, there may be a declining need for this feature in AV amps due to the fact that DSP can equalize multiple speaker setups that would be similar to manipulating gain controls. I would prefer the manual ability to match speaker volume- rather than introduce signal processing to equalize- but as technology advances this will become much more arguable. 

Both my NAD amps have gain. I have found that the NAD C298 sounds better when gain is in fixed position (full 29db gain). I have read where others have found their amps to sound better when in the fixed position. However, when you add a second pair of speakers, the interest is in either raising or lowering the sound in the second pair to match the first pair, so the gain in my NAD 275BEE (both amps have 29db total gain available) is set to about 1'oclock on the dial and thus is adding about 17-18 gain. While there is no discernible volume level coming from one speaker to the other, there is however, a differing sound signature coming from the towers and bookshelfs..of course!

The simple logic is this. One pair of speakers (LM Motion 40's) crossover at 500 & 2600 Hz, while the other (LM 35Xti's) crossover at 2200 Hz. Hence, the midrange is boosted (where most of the music I listen to is located) creating louder passages at lower amp volumes. Think of it as a tone control. 

NOTE: Many Parasound amps have gain knobs for each channel. As Erik stated, this can be useful for balance or multiple room setups. NAD amps only have one gain knob for both channels.

Also, it would be preferable to have the gain knob in the front of the chassis, rather than the rear, which means I have to perform yoga in order to get to it.

@emergingsoul 

Thanks! No water issues yet but the doors (threshold) needs to be replaced. Not going to be cheap..