High current switching supplies

[GasSavers_maximilian]

What sort of longevity hit do you get if you go right up to the maximum limit? Or is there a safety factor in there already?

[dkjones96]

I'm sure there is a safety factor in there, almost everything has one. Usually electronics are de-rated by 10%. The exception is stuff like large motors but they usually have a specified amount of time you can run them over.

I forgot to go into additional details on what happened. The power situation is fine but the cooling turned into a problem as the stock heatsink is capable of cooling the 2.4GHz at 66.2 watts TDP but falls behind grossly on the 3.2 with 82 watts TDP. The funny thing is that I didn't buy the Pentium 4 3.2 Extreme with 1mb cache because it dissipates 89 watts and I thought the cooler couldn't handle that. Maybe I'll pick one up now... hehe

The 'hot rod' heatsink I got is 41mm tall instead of the stock 32mm causing me to have clearance issues in the small form factor case. The stock heatsink/fan is 64.26mm from the top of the fan to the processor core so I'm modifying the case to take a 120x120x25mm side fan that will just BARELY clear the inside of the case. But, that 120mm fan will more than keep my computer cool.

I'll finally be done modifying this thing as I'll have maxed it out.

[dkjones96]

Holy crap!

Pentium 4 Extreme Edition 2MB

[GasSavers_maximilian]

I spent a fair bit less than that on all the new components for my current system.

I was thinking that if a larger number of caps were used and the voltage limit approached then resistor tolerances might start to matter. I imagine you'd need to use quite a few for it to really add up, though. Using better ones or just measuring them should get around it.

[dkjones96]

I don't know that I would do it to make up for voltage tolerances. Honestly, caps are so cheap now there really is no reason to skimp out on it.

When I make a virtual ground using two caps and two resistors I always make the caps meet full rail to rail voltage. If the virtual ground goes unstable for some reason and you get full input voltage across the lines you are still safe.

For example, I'll use two 16v caps in the supply even though the maximum input is 12v. I COULD use two 6.3v since each side of the virtual ground should only be 6v but if it happens to not be I don't want to be replacing caps because i was being lazy or cheap.

[GasSavers_maximilian]

Sorry, I was just having fun speculating. I get the conceptual equivalent of a song stuck in my head a lot. Even bothered to run some numbers of the tolerances...it's a sickness. I can't really see where I'd use it, either. More of a neat gimmick than something practical.

[dkjones96]

You said you are into digital so it is a neat gimmick when it comes to that. I deal with analog and vacuum tubes most of the time and it can be a money/time saver when you only need two resistors and a couple caps to create a ground, +V, and -V instead of using a rail splitter with a cap in front of it and two behind it. It isn't as efficient or as stable as the rail splitter but it is easier.

Yep, I said it, I work with tubes. I love my tubes!

[GasSavers_maximilian]

What do you use them for...audio?

I prefer my tubes tied, personally.

[dkjones96]

I do use them for audio but also power supplies, they are the ultimate in soft-start. I've made a few tube headphone amps and am in the process of building another one.

I'm going to be building a tube power amplifier for my new surround sound but I have to get my moving situation figured out first. They'll be interesting, I'm doing a point to point build using nothing but the schematic. It uses 11 tubes for 2 channels of audio(excluding power supply). The mono amp for the sub woofer uses 8 if you count the ballast tubes in the power supply