Buffer amp no gain

128 steps is overkill and can negative cable consequences. If one has to use more than the middle 10 of 20 the gain structure is messed up somewhere as in 700mV/500w amp on 101dB/2.83v speakers.

I don't think the number of steps in an attenuator is a particular problem, when it is a matter of relays switching in different resistors.  How does it hurt to have more steps?  A Levinson No. 32 preamp I owned had much more steps than that (.1 db steps).  I thought the Levinson steps were crazy small because one cannot easily hear a full db change with music, but, when I adjusted balance, I found that one can hear a .2db change in level of one channel, which explains why they offered such small increments of change.  

@ieales - Typically, the only people touting a MIRACLE CURE are the people selling a MIRACLE CURE, - unless of course you are talking about a properly oriented colored fuse.

@larryi  - The value of a buffer is for impedance matching as you noticed when comparing the passive Placette volume control to the unity gain Placette linestage, which is basically their volume control with a buffer.  I would not suggest a buffer as a tone control, although the improvement in impedance matching (compared to a passive) is typically heard as improved dynamics and tonal quality.  I believe with the Placette units, there are only two Vishay S-102 resistors active at one time so the only thing affected by their 125 volume steps is a that the user has a greater choice in controlling the volume, it would have no sonic affect whatsoever. 

Placette’s Q&A is a largely bollocks. If there are only two resistors active at a time that means there are multiple contacts added in the cct and all contacts are audible and the number should be minimized.

Every part has a sonic signature and a particular part may not be idea in a particular application.

Passive volume controls should be optimized for the system and one-size-fits-all may be fits-only-a-few.

""I know the sound of every resistor, every capacitor—everything. I know what tonal balance will be created when I mix this with that. So, when I started to develop the N11, I had a sound in my head. I made the schematic, optimized the layout to measure well, and then began listening and tuning with small parts. I adjusted the capacitor contacts, chose the correct parts for the desired sound, and determined what kind of silk screen on the printed circuit board would create the sound that would best fit Noble Line target customers." from Jurgen Reis in MBL Noble Line N11 line preamplifier