Project FAQ
I've never built anything electronic before. Can I build the TREAD?
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. Unless you use this board with an AC-DC "wall wart", you will be exposed to AC line power wires while building it. Regardless of the input source, the filter capacitors store enough energy to be hazardous. 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.
What's the best way to save money on parts?
The main thing is that none of the capacitors are strictly required, with the proviso that you can only leave out C5 if you're using an AC-DC wall wart. (In that case, the wall wart has a big filter cap in it already.) Replacing the trim pot with a fixed resistor will also save a buck or two. Beyond that, you're pinching pennies hard enough to make Mr. Lincoln grimace.
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 TREAD. 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?
Yes. Everything you need except for the power source (transformer or wall wart) and a heat sink is included. See the parts shop page for details.
How does it compare to a STEPS?
The two supplies measure about the same in my simple tests. However, I have read one report from someone who says the STEPS sounds better. The most likely reason is the superior pre-regulator filtering and the superior rectifier bridge in the STEPS.
After sound quality, the most important benefit of the STEPS is its compact all-in-one nature. If you want the transformer to be housed inside the same case as the regulator with the TREAD, you can of course use a toroidal transformer with it, as used on the STEPS. But the thing that attracts people to the TREAD is that it's cheaper than the STEPS. If saving money is your main goal, you're more likely to use a regular iron-core transformer instead; these are 33-50% cheaper in my experience. But when you do that, you have to put a lot of space between the transformer and regulator to keep induced noise low. Therefore, in practical terms, the STEPS is more compact than an all-in-one TREAD-based power supply.
If you power the TREAD from a wall wart to avoid this problem, the regulator will indeed take less space in the case than a STEPS. The downside is that a wall wart isn't as "pretty" as a regular AC power cord.
How does it compare to a Velleman K1823?
See the project history page.
I have a question. Who do I ask?
First, look through this documentation. It improves regularly with reader feedback, so the answer is often here if you look carefully enough.
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 TREAD-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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