One of our makers on campus, Jess, has spent a bit of time over the semester working on a homemade (or dormmade I should say) headphone amplifier (complete with 3D printed parts). I asked Jess about his process and how other students might be able to replicate his awesome project.
Have you built audio components or equipment before?
-Yes. I built a solid state guitar amp for my high school back in the day. The trick, however, is learning to both read a schematic and be thorough in the execution of these projects….It is easy to accidentally cut a corner here or there which usually renders things non-functional.
How did you find out about this particular headphone amplifier project?
I spend a significant portion of my time trying to contribute the DIY audio/hifi/headphone web culture. Coupling this with the fact there really are only two “grand master” first-source amp designers out there (Pete Millett and Kevin Gilmore), the choices were both sparse and thus easy. Sites I write for and read include Headfi.org in the DIY section, and I read head-case.org, Instructables, and many, many random blogs of folks who documented some of their projects. I pulled the amp I built, the “Starving Student Millet Hybrid” -SSMH-, directly from Pete Millett’s personal site.
Compared to other things you’ve built how difficult was this project?
I think the overall complexity makes it the most complex, but it was not hard to “make”. Again, taking extra time to do things properly, re-read stuff, and try not to do anything rash makes things easier, not harder. That said, the project just got significantly more difficult because a few crucial parts (MOSFETs) got destroyed during the “move the project into a final box”. I will need to rebuild much of the amp; but I learned a valuable lesson to build the project IN the box to start with to avoid this issue in the future.
Where did you build your project?
100% in my dorm room.
What kind of tools did you need?
Besides the schematic and knowing how to order from Mouser off a spreadsheet BOM, Ebay, and random folks who have extra RCA vacuum tubes in their garage, I used:
Scissors for wire stripping (my wire strippers are terrible, such that the scissor method was better)
Cheapo soldering iron from Amazon and solder
Alligator clips for debugging (usually a multimeter is handy, but there are no “bias voltages” in this circuit so that wasn’t needed)
Spare PCB P2P (point to point) boards for organizing the passive components
What have you learned by making this project?
Make the amp IN the box next time
I can read schematics better than I thought
I can do this sort of thing! Yay!
If someone wanted to make a headphone amplifier but had never done such a project before – where would they start?
Easy. The internet (and REALLY want to make one=unlimited time budget for proper learning). Read reviews of options, make sure there actually are reviews of the design. Reviews = documentation. Hit the forums- Most DIY forums topics on a single amp (often not even the power supply, JUST the amp!) are hundreds if not thousands of pages long. This seems way over most folks heads, but do this logically here……Get a document up and take notes as you go through the posts, writing down what you are sure you understand, helpful tips from folks who already did the build, and most importantly what you don’t understand. Inherently, everyone one else on the forum didn’t understand that at some point too, so it is usually a quick forum search tool or google search away to figure it out. Standard forum etiquette mandates knowing how to search a forum topic, because usually the same questions are asked every 3 pages….people only ever seem to look 2 pages back before posting. So don’t do that. Remember to take notes on everything- even if this is fun and a hobby, it is 100% real and serious research is required, so enjoy it. I didn’t realize that for a long time, which is why my projects were coming out half baked.
Jess’ headphone amplifier in it’s near completion:
All photos courtesy Jess Sullivan.
Find out more about audio projects at Jess Sullivan’s website.