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Does anyone have any plans, schematics or even photos of the inside of an unregulated power supply. I understand they are pretty simple to build and I would like to build a 75-100amp model.

Thanks in advance

Yes they are very simple.

Just take a look at the regulated power supply:
Power supply : 13.8V 25Amp power supply with LM723+2N6776

All you need is whats on the far left: The transformer, bridge rectifier, and the big capacitor(s) on the DC side of the rectifier. These components only need to be scaled to the current you expect to run.

If you cannot find a 100 amp transformer. It is possible to parallel two smaller transformers if they are the exact same model.

Always put the fusing or circuit breaker on the AC input.

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"Y'all mind hanging back? You're jamming my frequencies" -- Tangina in Poltergeist

power supply design

first schematic on this page is an unregulated dc power supply

have fun

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Bomb Diggity!
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Quote Bob85: "peoples' personal non factual opinions mean nothing to me period, BS is 10 cents a gallon anywhere you look for it"

High current unregulated power supplies make me cringe.

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Front/back ratio comes from the antenna. Forward gain comes from the wall socket.

I am either going to build a 75 - 100 amp for my class C super mega splatter box or purchase a Iota 75amp.

I have heard alot of great things about the Iota power supplies. They are going for 155 on ebay right now which is a smoking price.

The Iotas on ebay that I have seen for cheap are some sort of overstock or other odd lot that do not have factory warranties, unless they are used.

Maybe the cheapest way to go is to start with an automotive battery charger (100 amp) and put in a big filter cap.

Right now I run a single battery and a 200 amp fast charger I kick on when I'm on the key alot but the voltage drop is still there.

I think the 75 amp Iota on ebay would work. Besides the factory warranty is easy to get around.....

Why??? There are only 3 components that can fail in an unregulated supply- The transformer, the rectifier, and the filter caps. Regardless of what fails, the output voltage will drop,, so the equipment connected to the supply will be unaffected. This is NOT the case in a regulated supply:

The unreg supply I use for my linear idles at 16vdc, and drops to 14.3 vdc under load. The ripple (noise) is held to an acceptable level because my filter cap is 550,000 uf.

If you "cringe", it simply means that you don't really understand the diffenence between regulated and unregulated supplies.

Quite the opposite my friend. I made a career out of electronics and spent 22 years in the commercial broadcasting business and it is exactly because of what I DO know that makes me cringe. It has NOTHING to do with simplicity of the circuit and has EVERYTHING to do with the dynamics of a high current unregulated power supply.For a load that has a constant current draw they may be acceptable if the load can withstand the higher no load, or minimum load, voltage as would be the case in a radio where the voltage would be much higher on RX than on TX. Also with a load of varying current demand as in the case of an SSB TX the constant changes in voltage levels can and will mess with the IMD performance of the radio and can cause "FMing" of the signal. In the case of an AM TX flat-topping of the signal can occur much easier than with a well regulated supply. So you see my reasons are based on technical standards of which I have been accustomed too during my career in professional broadcasting and sometimes you just have to know what to look for before you can find anything wrong in the first place.

BTW I see you could benefit from a spellchecker too.

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Front/back ratio comes from the antenna. Forward gain comes from the wall socket.

He who lives in a glass house.........

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37OH - SSV - O773H