Project FAQ

I’ve never built anything electronic before. Can I build the TEPS?

This is not a good first electronics project. Build something else to get some basic skills before proceding to this project. Power supplies are not as forgiving of mistakes as other circuits.

Are power supplies dangerous?

Absolutely. You will be exposed to AC line power wires while building it, and the filter capacitors store a lot of energy. You must exercise due caution while building it to avoid electrocution. Wall power can kill!

This is a do-it-yourself project. That means that all benefits are yours, and all of the responsibility is yours.

There’s an awful lot of stuff to read here. Do I have to read it all?

The more you read, the more likely you’ll build the power supply correctly. Anything dealing with line voltage is dangerous, so it is a very bad idea to try and skip steps with this project.

How much does a complete configuration cost?

If you buy everything from Digi-Key, it’s about $70 for a standard configuration, including a Hammond 1455N12 case and the circuit board.

Digi-Key doesn’t keep the Hammond case in stock, though, so you’ll probably end up splitting the order between Digi-Key and Mouser. It’s possible to save enough money on parts to cover the extra shipping cost by shifting most of the parts order to Mouser, as their prices are generally lower.

• Use a plastic project box instead of the Hammond enclosure.
• Leave out the line filter: C1, C2, R1, and L1.
• Use a generic regulator. A 50-cent off-brand LM317 still gives 99% of the benefit of a $3.75 LT1086.
• Use only one filter capacitor.
• Leave out optional capacitors C4, C6, C7, and C8.
• Short VSET. (I.e. No adjustability.)

If all of that doesn’t save enough money, I recommend that you buy the TREAD. It’s similar to the TEPS, but without the on-board transformer and audiophile configuration, so it’s a lot cheaper.

Can I use parts not mentioned in your parts list?

The parts table doesn’t list everything that will work. It’s more a list of examples than anything. Before buying a part not mentioned on these pages, do a search in the DIY archives on Headwize and Head-Fi; someone else may have used the part and reported on it, or there may be advice there saying why a given part is a bad choice for the TEPS. If you can’t find any information there on the part and you aren’t savvy enough to be able to pick parts on your own, please ask on the forums about it. Often a part that looks like it will work, won’t.

I don’t want to chase down all these parts. Can I buy a kit?

Sorry, no one’s offering kits right now, and I have no plans to ever offer kits. I don’t believe there is One True Way to build the STEPS, but I’d only be able to offer one configuration in a kit. Contrast that with the TREAD, which has a simpler function, so there’s less disagreement about ways to populate the board. As a result, I do offer a kit for that project.

If you can’t find it here, do a search in the Headwize and Head-Fi DIY forum archives. Asking a question that’s been answered before (sometimes many times before) is a waste of the other forum members' time and yours. If the answer is in the archives, it’s quicker to search the archives than to post the question and wait for people to answer. Don’t limit your searches to TEPS-specific posts. Any question you have about this particular power supply is probably relevant to other LM317-based power supplies.

If the answer is not in the archives, go ahead and post the question to the forum. It’s better to post publically than ask people via email or private messaging because you get more answers by posting publically, and the answers are archived for future builders to find.

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