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This Homemade Headphone Amplifier Is A Work Of Art
- raverbashing 15y agoBeautiful! It's very difficult to assemble a circuit without a substract (PCB or other), and those wires aren't going to stay straight by themselves. The shining capacitors are a special touch (I guess he removed the plastic cover on them) I'm not sure about the sound quality though.
- ams6110 15y agoEver look inside an old tube amplifier? It's all point-to-point wiring, no PCBs.
- shabble 15y agoIf you're lucky it'll have some amazing cable lacework[1] holding the various bundles together. Sometimes I've thought that the insides are actually better looking than the case. It's a shame that it's dying out in favour of cable-ties and velcro, although the effort involved in both learning the skill and creating/reworking bundles means it's seldom the most economical approach. I think it still lives on in some Ham radio groups teaching materials and standards though, as well as niche environments or reliability critical applications like (aero-)space [1] https://en.wikipedia.org/wiki/Cable_lacing https://en.wikipedia.org/wiki/Cable_lacing
- bcl 15y agoDepending on how hard you drive it heat dissipation may be an issue. It sure looks nice though.
- daeken 15y agoHe wrote more about it and covered heat at http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cmoy-freeform-headphone.html http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cm... Seriously nice work. Tempted to build something similar myself.
- raverbashing 15y agoNot really. A headphone (even a big one) uses little power. For this amp, output power is around 200mW apparently. Sure, acrylic is not the best conductor of heat around, but I'm guessing the tight coupling to the chip casing and low power makes it a non issue.
- HeyLaughingBoy 15y agoProbably not, it's encased in acrylic. Acrylic has a thermal conductivity 10x that of still air.
- moe 15y agoHe could make a killing selling these devices - if the sound quality is good and if he can find a way to produce an audiophile-sized batch. I'd pay in the $100 range for one without thinking, real audiophiles would probably pay much more.
- revscat 15y agoUntil MegaCorp comes along and slaps him with a patent infringement lawsuit, of course. I'm pretty sure there are a large number of patents around amplifiers of various kinds. Hopefully I'm just being overly cynical.
- savrajsingh 15y agoMost, if not all of those patents are expired (20+ years old). Once a patent expires, it's in the public domain and can't be re-issued or re-assigned. So yeah, overly cynical in this case. :)
- pjscott 15y agoThis is actually a pretty simple op-amp circuit. The tricky amplifier stuff is all in the OPA2107 chip; everything else is either part of the power supply, or a straightfoward arrangement of resistors and capacitors to get the op-amp to do the right thing. The really cool part here is the assembly. That thing is very pretty.
- HeyLaughingBoy 15y agoUnless he can find cheap workers, the labor to produce it would make $100 each a steal. No way does it take less than an hour start to finish to build that. I'd start pricing at around $350 and see how that flies.
- icegreentea 15y agoIf you invested in some jigs to hold the components while soldering, then I could see significant time savings. The time to cure the resin really doesnt count. I woukd estimate that with the correct jigs, you could complete the soldering in half an hour tops. I count roughly fifty solders on thus thing, most of them pretty simple. You also overestimate the per hour cost of semi skilled labor. The skills involved arent that involved or difficult to learn (especially with the right tooling).
- crikli 15y agoWhat's the application for such a thing? I'd buy one just because it looks completely cool but I'm not sure what I would do with it.
- philbo 15y agoIf you're using headphones with a high impedance, the power output of device like an iPod or whatever may not be high enough to deliver enough volume for your liking.
- simpsond 15y agoThis little amp allows you to drive high impedance headphones with something like an ipod.
- deleted 15y ago[deleted]
- andrewcooke 15y agothe speaker in a headphone cup works as follows: current flowing through a coil of wire that is fastened to the speaker cone generates a magnetic field, which interacts with the magnetic field of a fixed magnet, moving the cone and so generating sound. the cone movement, and hence volume, is proportional to the strength of the magnetic field, which is, in turn, proportional to the current through the wire and the number of turns in the coil. there is a tension here, which is not obvious. the problem is that the coil is fastened to the cone, and so moves with it. for a responsive cone, we want as light a coil as possible (a heavy coil will give the speaker cone inertia, making it less faithful to the music signal). but if we make the coil lighter by reducing the number of turns we reduce the volume; if we make it lighter by making the wire thinner we increase the resistance, lower the current, and again reduce the volume. one way to work around this is to supply a higher voltage to the coil. that can counteract the higher resistance of a thinner wire, and so provide the same volume with, hopefully, better sound quality. but the output voltage of many sources (particularly portable players) is limited. so, finally, all should be clear: people use amplifiers like the one here to increase the available voltage so that they can use higher impedance, and arguably better sounding, headphones.
- cake 15y agoLet's just hope that none of the capacitors break in the near future. While it may look cool, it's a complete disaster for maintenance.
- evincarofautumn 15y agoAgreed, but I think the look rather outweighs maintenance. It’s such a simple device that you’d hardly care to maintain it. You fry a capacitor, it’s one of a couple dozen parts; the thing probably wasn’t terribly expensive to begin with, so you just frown and replace the whole shebang.
- bluesnowmonkey 15y agoI suspect that maybe one in a thousand people have the tools and wherewithal to open the case of an electronic device and replace a broken capacitor.
- DougBTX 15y agoFar fewer than that would know 1) which components are capacitors, 2) be able to tell which capacitor was broken.
- Natsu 15y agoA blown electrolytic cap is not hard to diagnose. The top of it pops open and crap comes out of it. I figured out both what they are and how to tell if one has been blown when I was a teenager, all by myself, sans internet.
- astrodust 15y agoEven fewer would have the equipment to fix it and the determination to source the part. A fraction of those would have the skill to pull off a successful replacement.
- Aloisius 15y agoI think it would make a lovely paperweight regardless.
- ortusdux 15y agoHis site: http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cmoy-freeform-headphone.html http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cm...
- jfb 15y agoThis is a lovely piece of work; I think it's missing the point to speculate on possible profit margins, or the magnitude of a kickstarter project; the thing is the point here. Something so well turned out makes me want to make things, not buy them.
- jentulman 15y agoTotally agree. Up until seeing this I never thought I even wanted a headphone amp, know I feel like I need to make one this lovely. Projects like this are why I like to make things, not for the thing, but for the make.
- jwr 15y agoYour comment precisely describes the "Hacker Spirit" that I expect to see around HN. These are the kinds of projects that I gladly upvote. Hacking (often just for the fun of it) is so much more rewarding and in the end provides so much more value than the usual techcrunch-style drama that often occupies most of HN home page.
- benihana 15y ago>is either a very dedicated audiophile or just has a lot of time on his hands. Why this passive aggressive line in an article praising how cool and pretty this amp is?
- RexRollman 15y agoVery cool. This made me realize that its been a long time since I visited the Head-Fi forums.
- gouranga 15y agoI bet that is noisy as fuck. Long traces and no shielding - utter turd. Form should never compromise function.
- slug 15y agoAlthough there's better ways to express it, you might be right. I wouldn't want this thing next to my RF power amps, cellphone devices or power tools. Turning deaf at a turn of a nearby equipment it's probably not nice. Nonetheless it looks pretty, but not as pretty as the glow of my now defunct old tube radios.
- qq66 15y agoThe function of this amplifier isn't to achieve the best amplification at the lowest cost -- it's to be a curiosity piece that actually does something. It seems to perform this function admirably.
- brohee 15y agoYet the maker says exactly the reverse in his blog... "Although there is no metal shielding as you would have in a conventional chassis/PCB the amplifier exhibits no unwanted noise or RF interference as you may associate with an open chassis design such as this it is dead silent even though it is next to my mobile phone and WiFi router."
- gouranga 15y agoJust because it's next to the device doesn't mean it'll induce current in that position or at the right frequency to generate audible noise. Testing is much harder than that. I bet someone will build a clone and find out the hard way.
- muhfuhkuh 15y agoIf pricing seems to be a question, just put the project up on the most accurate consumer-pricing a/b simulator of all time[1]. [1] http://www.kickstarter.com http://www.kickstarter.com
- kfury 15y agoAnyone know about the thermal conductivity of the cured resin? If it's a thermal insulator I wonder if the capacitors might burn out after prolonged use because there's not enough heat dissipation. Oh, and I want one.
- sbierwagen 15y ago~10x that of still air. (from higher up in this thread)
- DanBC 15y agoThere are lots of really easy to make headphone amplifier plans on the www. Some of them would be suitable for beginners to electronics. The practical aspects are easy enough. And the theory is reasonably straightforward. And people enjoy putting them in nice cases. Often these are lumps of wood, or aluminum; this resin case is a lovely example though.
- dimatura 15y agoThis style (using no circuit boards) is pretty popular in the BEAM robots community, where it's known as "freeforming". Here's a random example http://www.flickr.com/photos/mohitbhoite/5708836052/in/photostream/ http://www.flickr.com/photos/mohitbhoite/5708836052/in/photo...
- joshontheweb 15y agoThis would be a perfect Kickstarter project. I'd like one.
- jonah 15y agoIt might be more insightful to build one yourself.
- joshontheweb 15y agoNot a bad suggestion. Seeing it build with discrete modules instead of a circuit board make it seem like it wouldn't be that hard.
- kragen 15y agoThis worked out beautifully. I hope we see a lot of new electronics projects built like this in the next few months. His choice to pot the electronics in transparent (apparently polyester) resin reminded me of this unfinished design provocation of mine, "The Egg of the Phoenix: a computational time capsule": http://www.canonical.org/~kragen/eotf/ http://www.canonical.org/~kragen/eotf/ Specifically, I was thinking that potting solar-powered electronics in transparent resin would be a good way to ruggedize them, so that your electronics might have a chance to keep working for decades or centuries.
- phodo 15y agoDoes anyone know what the lifespan of the resin is? Is it longer than 6 months? For example, see the link here that states this resin has a 6 month lifespan. Wondering if you can get them for longer lifespans measuring in years. http://www.dickblick.com/products/castincraft-clear-polyester-casting-resin/ http://www.dickblick.com/products/castincraft-clear-polyeste...
- ratsbane 15y agoThat's the shelf life for the uncured liquid. After it's been cured the lifespan is almost forever.
- zerostar07 15y agoIs that enameled copper wire or how does one solder on copper wire? Also, what did he do exactly to avoid damaging the capacitors?
- Someone 15y agoVery nice, but seeing that made me wonder whether this can be improved as follows: instead of soldering, drill holes in the copper wire that are slightly smaller than the thickness of the component wires you want to attach. Then, heat or cool both enough for the component wires to fit through the hole (thermal expansion factors will hopefully be different enough for this to work), put them in and let the device go back to room temperature.