Allo CM board makes a profound difference to the sound of the base Volt+.
The base Volt+ has 1 x 1000uFD to filter/supply both channels of the 3118.
In this configuration, the mid and low bass are very weak. This is driving
very difficult 2 way bookshelf reference speakers (86db/W/m).
Trying differen SMP bricks, didn't not fix the problem. I went up to 24V @ 5A SMP,
then went back to 19V @ 10A (which had more resolving power). People also
seem to be leaning towards linear supplies over SMP bricks.
Then I tried a CM board (2 x 1000uFD) as a pre-filter into the Volt+.
The mid and low bass were markedly improved. Still not as firm and control
as the amp I was comparing it against (which was 140W AB with 30000uFD
and costing 60x more $).
I'm definitely going to increase the pool up to 7K uFD with fast ESR caps
as the next stage.
Also, the wiring to the speaker output terminals on the Volt+ Step Attenuator
are very lacking. Very thin wire (which may account for the thin mid/low bass)
and not solder (tension with a screw) which came loose (had to debug this).
The upper end is spot on. Imaging of solo vocals and single instruments are very
convincing.
But for the price point, I really can't complain.