Full detailed sound at 30 - 40 - 50 dB


I love the nuance you can hear when listening to music at loud volumes, but unless no one is home, it’s not considerate or feasible to listen at such high volumes. Plus I just had a baby so everyone is always home and volume levels are limited to 40ish dBs. 

Any recommendations for getting the most detail at these volumes? Additional gear or recommended integrated amps?

My NAD 7175PE has a loudness button which boosts the treble and bass a little, and that certainly helps things in the Kitchen. 

My living room amp is a Rega Brio-R which doesn’t have any tone controls. 

Any thoughts? Thanks!
leemaze
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@atmasphere 

Take a look at the distortion curves of a typical solid state amp. At a certain lower power level, the distortion is at its minimum and as you go to lower levels the distortion can be significantly higher! This is not a given with tube amps, even push-pull amps (our amps are push-pull but distortion linearly decreases to unmeasurable as power is decreased).

So that power level is about 5-7% of full power with most solid state amps. If you've ever heard that bit about the 'first watt' being the most important, that's because its all about distortion (or in this case, the lack of it). BTW, Nelson Pass has a set of solid state amps called the 'First Watt' amps and they are so-named because they diverge from the usual solid state amps in that they too are very low distortion at low power levels. Their designs are also quite minimalist (even simpler than and not unlike tube amps in that regard) although they don't make a lot of power.

If you want good resolution so you hear everything (including good bass) at lower levels, this is what you have to do: tubes or a low powered solid state amp like a FirstWatt.

Which First Watt would you recommend to the owner of high efficiency speakers (101db, 16 Ohm) ? Currently using push-pull tube amp designed (OEM) by Trafomatic Audio for WLM Acoustic back in the days. 
I recommend you move the baby into the audio room and acclimate the kid to your hobby now. I learned to fall asleep to a bunch of dudes wailing on guitars in the next room...and look where it got me...posting bad advice on Audiogon. :-)
Congratulations on having a baby. One of life's great blessings.
Which First Watt would you recommend to the owner of high efficiency speakers (101db, 16 Ohm) ? Currently using push-pull tube amp designed (OEM) by Trafomatic Audio for WLM Acoustic back in the days.
A lot depends on your preamp as the single gain stage units need more drive.  I'd be looking at one of the 20 or 25W units since they will be making less power than that into 16 ohms.

FWIW a speaker like that is ideal for tubes. We make a 30-watt/ch OTL that would work great on that.