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5V 3A PSU

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Fatmangolf View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 19 Mar 2018 at 7:37pm
Like!
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 19 Mar 2018 at 8:51pm
Great to see it taking form. Looks really simple/basic, which is usually for the best. "Hack away at the unessential". The high price I pay for it will be for the attention to detail, skillful production and for your invested time in its conception.
We do not see things as they are. We see things as we are.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 20 Mar 2018 at 6:04am
I doubt it will look simple/basic when wired together. Hard-wired products seldom do. I will hand it over to John C for his lacing cord skills.

Not shown in the image are: the other binding post set (there are two outputs voltages remember), and the ground or earth lift switch. Some items will not benefit from having an earthed ground, but some will.

As this is a metal chassis it makes sense to earth it to the mains as a class 1 appliance. However, the 0V connection to most wall-wart powered products is not earthed to the mains, so the power supply output 0V is best left floating, or it could cause a hum loop. The switch allows it to be floating or tied to earth via the power supply chassis.

Protection against radio frequency interference is provided by the usual 100R||100n resistor capacitor arrangement, which connects 0V-out to earth at high frequencies.

Hoping to get the chassis piercing drawings done today and a case prepared for fitting out.


Edited by Graham Slee - 20 Mar 2018 at 6:06am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 20 Mar 2018 at 6:58am
Thanks Graham.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 21 Mar 2018 at 8:22am
My how things have changed in 20 years...

It would seem the father, son, holy ghost and all British tool manufacturers, took the last train to the coast! (paraphrasing a lyric by Don McLean)

What used to be easy is now downright impossible. Sorry to our Chinese readers but Chinese tool steel isn't, period. God put the best iron ore under Sc**thorpe for a reason. The trouble is nobody in the UK understands that (but Boeing thought they did and set up in nearby Rotherham... they're in for a shock... Sc**thorpe iron ore is history).

The tools I used to have went through aluminium sheet like hot butter. Not any more.

So plan x is out. Getting the chosen case customised by its manufacturer is out, as they're in Japan. So it looks like going to the last remaining proper engineering shop in the UK. Huddersfield again!

(and people think our cases aren't cute?! At least they're British!)



Edited by Graham Slee - 21 Mar 2018 at 8:26am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 21 Mar 2018 at 7:16pm
The latest prototype of the 5V 3A power supply is now being tested.

Voltage regulator data sheet load regulation never takes account of things like wire losses or PCB trace losses, so you will read about fantastic regulation of 0.03%, which simply doesn't happen in the real world. It is more like 2% no load to maximum load.

The power supply has been measured at 5V for 3A loading, and 5.1V no load, and similarly on its 3V3 output.

Overvoltage protection crowbars the voltage regulators into short circuit shutdown, and in practice the outputs assume approximately 1V. This being the forward voltage of the SCRs used to crowbar the outputs.

At present the crowbar circuits are too keen, and will be padded out to 5V6 on the 5V output, and 3V6 on the 3V3 output.

Still some distance to go but it's getting close.

5V 3A power supply 3V3 output

5V 3A power supply rear panel

5V 3A power supply plan

5V 3A power supply front



Edited by Graham Slee - 21 Mar 2018 at 7:43pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 21 Mar 2018 at 10:16pm
I really like your style of work; very methodical and smartly presented. Looks great.
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