You mean like statements like this that ONLY apply to pure-class-A and make assumptions about heat-sink materials, power supply architecture, etc. that are not a given in all designs.
One pound of weight for every 2 watts is a good litmus test for
evaluating Class A amplifiers. An amplifier weighing less might not be
pure Class A. It might be almost Class A, or it might be one of the many
products which achieve a Class A designation through trick circuitry.
What's funny is that people will quote the likes of Pass when it suits them, but ignore the other things he writes when it suits him, like
Large inductors in series with the transformer primaries and secondaries
can be used to stretch the duration of the charge pulse to the power
supply capacitors, improving regulation and reducing noise.
... those large inductors negate heavy gauge power cords.
Of course, not everything that Nelson pass says/rights is entirely accurate either:
Also, it helps if the power supply capacitors before and after the
switcher are very substantial. This is typically not the case, since one
of the primary motivations to use switchers is to save money.
Power supply capacitors before the switcher are not "substantial", as small values are essential to achieve good power factor and THD, a typical design goal of AC\DC switching supplies. As a matter of fact, substantial capacitance on the front end of an AC\DC switching supply will reduce the requirement for output capacitance to achieve the same performance and will reduce the overall cost to achieve the same performance.
