great man keep it up! more power to you.. from Philippines

What's up. Watching from Sur Baja California

For Audio amplifier applications it is more realistic to look at the DC or 1ms line in the SOA graph for both power supply and output sections (specially for output section) For example recently i had a class AB amplifier which was rated for 200w for each channel and when you consider the rail voltages you could have seen it was rated up to the DC line in the SOA graph (1.25 A for each transistor at 50V rail voltage and there were 4 transistors per channel which totals to 5 amp and considering a 8 Ohm load its all makes sense)

Saludos amigo desde MEXICO

hi from acapulco mexico

​ @barevids I tried explaining this in the video live chat, if you recall I was the one who pointed out the SOA graph to you, I promise I'm not trying to confuse anyone and only wish to help. I feel guilty for pointing it out and not fully explaining it so please hear me out... The easiest way to understand this is to look into the operation of a lab bench "variable load" where a mosfet is used as a variable resistor to test a power supply and the SOA is most applicable. The SOA graph can be broken down into two sections, left = saturation region, and right = linear region. While operating in the saturation region the mosfet Rds(on) is at it's lowest point, typically the datasheet Rds rating and the voltage across it is a function of the current flowing through it (Vds=Id*Rds(on)). In this saturated region the Rds is very low and the voltage across the mosfet is very low (under 1V). So on the SOA graph we are operating on the left side, where Vds is low and resistance it is also very low. Therefore the power dissipated would be very low and subsequently wouldn't need to be considered in thermal management(aka power dissipation). The right side of the SOA graph is the "linear" mode where the mosfet isn't fully turned on and can be interpreted as a variable resistor, with it's resistance always greater than the datasheet Rds(on) rating, in this region any current flowing through the mosfet would cause massive thermal considerations as it's power dissipated would be defined by Pd=Id^2 * Rds. You can easily determine this by dividing the voltage by the current in the SOA, if the resistance value is greater than the Rds(on) rating then the mosfet isn't fully turned on and operating as a variable resistor (aka linear mode). In a SMPS (class D amplifier) the mosfets are operated in the saturated region(fully turned on with lowest possible Rds) for the duration of the pulse and the only time Rds isn't equal to the Rds(on) defined in the datasheet would be during a transition (switching) event which is in the nanoseconds duration so it's typically only considered in the switching loss calculations. So looking at the right side of the SOA graph to determine the ampacity of the mosfet operating in the saturation region isn't correct because the voltage across it (Vds) is extremely low. Another approach is to consider the power dissipation rating of a mosfet and how it's calculated, power = Vds * Id, which can be rewritten as... power = Id^2 * Rds. From this equation we can determine that the resistance seen from drain to source is directly correlated with the power dissipated. When a mosfet is saturated (fully turned on with the lowest Rds possible) it's able to pass massive amounts of current without heating up. But when operated in the linear region (not fully on and operating as a resistor) the resistance is much higher so the current rating is drastically lower because the power dissipated is a function of the resistance multiplied by the current squared. If this still isn't clear I can make a video explaining in a longer format showing all the math and theory involved. I spent about an hour making sure I typed this out clearly and accurate, if anyone finds this helpful please give it a like or reply. If you feel I made an error please point it out so that I can address it.

Hello sir. I was recommended to ask you this to see if you knew. Have a huge curiosity on amp parts, layouts, and so much more. My question as of this time is for the caps. If they are all the same part and one amp has more total value of caps on the input power side vs having less on output and another amp have the exact opposite what would the pros and cons be for music, power, efficiency, sq, and so on. If you have a Facebook I can show you pics to be better detailed of what I’m asking. Thank you for any of your time.

so whats better the big boss or the smarts?

Yo

This video is sponsored by sparkling water?

Clean up your bench man! Lol.