Power Supply Caps - Standard vs Audio

[AndrewT]

adding a low esr cap to an electrolytic is especially a risky combination.
It's the low esr plus the trace inductance that creates the two pole system and can oscillate.

adding an identical electro to the first electro is very unlikely to oscillate.

 

[marce]

That is why Gigabyte motherboards have double the thickness!

(In before audiophile brands start marketing products with quad thickness... should i have kept my mouth shut?)

There is more to it than this, but it is very good marketing.....

 

[marce]

Nah, they'd just put black solder resist on it and call the PCB "special"...
The colour of choice seems to be green, 99% of the PCBs that pass my hands at work are some variation of green. Why? I don't know. We do see some other colours, like red, black or blue. My MSI motherboard is poo brown.... yuck...

This Gigabyte add boasting 2oz (i.e. 70 um) copper is another example of marketing at its best. The use of 70 um copper isn't really special, but because of the higher cost only done when needed (large currents). If you look at the spec of a complex multilayer pcb, it's not unusual to see varying thicknesses depending on the function of a layer. No more copper is used than needed to save cost, even in expensive industrial applications.

Green is best.... you get the best resolution important for SMD designs. Green is the best colour for inspecting boards (it is where the eye sees the most detail, hence most digital sensors have 2 green to the red and blue, Bayer) and when boards had to be heavily inspected by human eye there was a lot of work done on the effectiveness of different resists finished, satin green was the preferred choice for accuracy, minimised strain on the operator etc.

I do boards occasionally with 4 and 6 ounce copper inner layers, mainly on big SMPSs (100A @ 250V sort of thing) for current capacity mainly. Changing your ground planes to 2oz on a PC motherboard, I would rather see the layer structure used in more bespoke PC designs (usually embedded in kit) where you would have 10-16 layers with multiple ground planes, allowing better signal impedance control and power/ground pairs for increased planar capacitance.....