Are there passive attenuators that don't zero volume and only offer one input ?

@bigwave1 - The base Axiom uses a shunt to ground design that they indicate keeps the signal path away from the Alps potentiometer. I believe Joule did something similar on their preamps. The upper end Walker Mod models use Khozmo’s discrete resistor attenuators. I looked at both Axiom and Khozmo earlier in the year and went with the Khozmo. I liked the small form function of the Axiom but was ultimately able to have more/better features with the Khozmo, including L/R channel control, larger display (for each channel), and my choice of resistors. Khozmo also has an upscale brand, Hattor, with even more feature possibilities such as an active stage and more substantial chassis, but I am not convinced those would sound any better than the Khozmo line for a purely passive unit. If you want the choice of switching from passive to active using a high end op-amp or even a tubed stage then look at the Hattor line.

Perfect, thank you mitch2

Which is to say it is essential I should think to be able to zero volume, and have more than one input, do you agree ?

No.
Every contact, additional component and wire/trace affects the sound. Anything below -20dB is pointless with properly configured gain structure.

Is it HiFi or sonic wallpaper?

I own the top model Luminous......3 in, 2 out, with remote ( single ended ), and I am very pleased with it's performance.

No.
Every contact, additional component and wire/trace affects the sound. Anything below -20dB is pointless with properly configured gain structure.

Is it HiFi or sonic wallpaper?

If it is contact less already on the signal path then you can have as many inputs as required, and zero volume too.

To do that arrange LDR anodes of each series pair to be switched on in turn - according with your stereo inputs. To zero volume needs your design to power shunt anode separate to series anode, it needs also NOT to ground the LDR cathodes, rather arrange a regulated  jfet current sink.

Your volume control is arranged between shunt cathode and series cathode.  You then arrange via LM317, with a higher potential on its adjustment terminal, place its Vin to the series cathodes and adjust for silence with resistance from the higher potential to Adj. As lower volume positions are reached, the start circuit thus named influences the series resistance readings, and causes extreme resistance on series pair at lowest volume, creating ability for silence. 

The start circuit is accompanied with another circuit called the continue together they interact together to improve relationship of the entire circuit for excellent current delivery and resulting audio performance.