I miss my Loudness Button and Tone Controls....

I once had the NAD 162 preamp also. These are pretty good preamps. It didn't have a loudness button but had very good tone controls that operated at the frequency extremes so were not heavy-handed at all...subtle yet effective.

Anyway, I've found speaker placement and listening position to be way more effective than tone controls. 

As I've upgraded, I've generally found my new equipment to be more detailed, delicate and yet more neutral in some ways. Less flattering of bad recordings. However I do get excellent bass presence at low volume without tone controls or loudness button. Something I didn't get with my NAD preamp with tone controls. 

I’ve had Maggies for most of the last 40+ years.

All that time I HAD to have bass & treble controls to compensate for lower level listening.

Last year I had to downsize and after shoehorning my 5½ foot tall speakers into the smaller room, I finally came to the heartbreaking conclusion that it was time to sell the Maggies.

I bought a pair of Kef R300’s. Not the most efficient speaker in the world but way more efficient than the Maggies had been. I also got a Parasound NewClassic 200 Integrated amp. It was represented as being accurate and musical, plus it had my precious bass, treble and even sub level controls...all of which could be adjust via remote from the listening position.

I don’t know if it’s the sensitivity or the Coax drivers, but I haven’t used any of the tone controls since getting the room set up for the last year...I just run the controls flat and it sounds great.

Sure, I miss the humongous sound stage of the Maggies, the the Kefs hold their own and the sound at lower volumes is excellent.

Zu’s are very sensitive, yet your not having good luck...so maybe it’s not the sensitivity that is helping me out here. I haven’t listened to Zu’s so I have no idea how they are voiced.

Tone controls are good for two things:

Fixing room anomalies.   Second best to fixing the anomalies.

Letting you play record producer.  Probably only for kids.

I have a Technics SH 8020 EQ love it  great old school

I use BW speakers and they sound wonderful at any volume.