are all amps equal

I wonder what explanation "experts" give for power cord differences - that will be fun.

I'm no expert on building or designing power supplies and nor do I work for a utility but one can't help thinking it might be a combination of;

1) Dirty Power (perhaps caused by other home appliances)
2) Inadequate power supply design
3) Ground loops

Since manufacturers are always looking to reduce cost to meet a competitive price point I suspect inadequate power supplies are quite often the culprit. After all a consumer is more likely to buy an item if it has an expensive face plate than if it looks cheap but has an expensive power supply.

Of course it requires that you believe that good equipment design should trump the need for non standard power cords. I have a power conditioner and it helps on one of my components - I still blame the component design however, and do not ascribe exceptional properties to the power conditioner or its power lead.

So we agree in one sense but disagree as to the cause. In the same way I would blame equipment design and compatibility in the case that the interconnects or speaker cables made huge improvements (again I blame the equipment or my poor choice of what to cobble together rather than ascribe amazing audio properties to mere wires)

Just a different viewpoint - no flame intended.

Shadorne - I can make case for bad power supply being less affected by power cord than very good one. Here it comes:

Average value of current being drawn from power supply caps is taken from transformer in very sharp pulses. These pulses heat up transformer (higher harmonic content heats-up the core and much higher rms value than average value heats-up the copper) and appear on the power cord. Sharpness and amplitude of these pulses can be determined from diagrams: conduction angle that depends on ratio of transformer output impedance to ESR of capacitor.

Amplifier with poor capacitors (higher ESR) will have longer pulses of smaller amplitude and will possibly be less dependant on gauge of power cord (for voltage drops) or shielding (for polution).

Mentioned conduction angle is a Catch 22 for designers - in order to know how big transformer should be (to accomodate for bigger losses caused by sharp current pulses) conduction angle has to be found. It require value of transformer's output impedance - not known since transformer is not designed yet.

I made this a little bit technical to show that anything can be proved. Somebody can probably make equally valid case that proves just the opposite.

Kijanki,

There is a lot of distortion in power supply transformers - AC power has all kinds of terrible harmonics to begin with and can often look more like a square wave than a sinusoid - but who cares - the idea is to prevent all this stuff from ever reaching the power supply rails or the audio signal by careful design.

Kijanki, I'm definately with you on this one . . . an interesting comparison is the differnces between these conduction-angles and time-constants between tube and solid-state amps. Tube amps have lossier power transformers, (sometimes) tube rectifiers, C-L-C or L-C filtering (and more RC for the small-signal stages) . . . which all seems to have the effect of making the filtering time constants much longer than a typical SS amp - in both directions.

Then there's another little detail that is so often ignored - the fact that the vast majority of "DC coupled" solid-state amps are in fact capacitively coupled . . . Kirchhoff's law says the AC ground current from the speaker has to go somewhere, so it returns through the main filter capacitors. It's just that they're in the feedback loop all the way to DC that makes DC offset possible at the output, thus making it "DC coupled".

Kirkus - Tubes should be better then, for reducing power related hash. I'm getting interested in power cables and their effect on the sound. My Benchmark DAC has regulated linear supply while my Rowland 102 has a switcher. I have to find some testimonies on power cables - I'm not sure where to start - possibly with the same brand as my interconnect and speaker cable (Acoustic Zen). Is there any science behind power cables other than gauge, inductance and shielding?

Your DC coupling observation is very interesting one and suggest that good sound depends more on the quality of this cap than we think. Good low ESR low inductance caps are expensive (like slit foil type) and fixing cheap ones with Mylar cap in parallel can make it worst by adding lossless cap in parallel to inductive cap creating in effect resonant circuit that rings (and is in the signal path).