Pure output current is not the whole story. The power supply should
offer a low source impedance at the frequency of operation - there's no
point being able to supply lots of amps at DC if the source impedance
increases rapidly with frequency. You only have to look at the
schematic of an Audio Research or Naim amplifier to find that as much
goes into the power supply as the amplifier itself. In effect, you use
a wideband amplifier to supply DC to the load.

With more basic power supplies, you can go some of the way by simply
decoupling the supply line to ground with one or more electrolytics,
bypassed with one or more polypropylene and ceramic capacitors which
behave better than electrolytics at higher frequencies. The electronics
effectively sees the decoupling capacitors as a low impedance shunt to
ground from the power lines.

For an SB3, a DC current of 3A is plenty and I daresay it already has
the decoupling I mentioned.

My approach to replacing the switched-mode power supply with a linear
one would be (haven't done it yet) to provide a wideband regulator,
remote sense (so that the voltage being controlled is the one reaching
the SB3 power connector allowing a longer cable and not being concerned
with voltage drop), and possibly a capacitor upgrade in the SB3 itself.
Not especially keen to void the warranty, so may just make do with the
first two.

However, to my ears, there's not a lot wrong with the SB3 as it stands.


-- 
DitherMan
------------------------------------------------------------------------
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