
This Homemade Headphone Amplifier Is A Work Of Art - ot
http://this8bitlife.com/this-8-bit-life/2012/4/16/this-homemade-headphone-amplifier-is-a-work-of-art.html
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jfb
This 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
Totally 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.

~~~
platz
If I could make things this beautiful (and it's not pure form, it's also
functional), I'd feel a _lot_ better about what I do.

~~~
lloeki
> and it's not pure form, it's also functional

Understandable, honest, unobtrusive, thorough, and useful. Really good design
by D.Rams definition.

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moe
He 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.

~~~
HeyLaughingBoy
Unless 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
If 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).

~~~
HeyLaughingBoy
Of course you need fixturing: that's a given. Remember to account for the time
and materials making up fixtures.

I would price the labor at around $15-$30 per hour minimum. You aren't going
to farm this out to an assembly shop (not enough volume) and there isn't
enough money in it to hire employees and deal with that overhead, so you're
down to finding a FOAF or a student who can solder and is reliable. Factor
into that that the person must be supervised.

Next, this isn't just assembly that has to work; it has to look good, so the
assembler needs the skill and attention to detail to provide that. That means
either you get lucky or you have a lot of rework, or you watch him closely.
Soldering is not enough: need to pay attention to the cut ends of those thick
conductors. The component lead terminations must look good and the components
themselves should be fairly regularly placed and not look sloppy. Remember,
you're selling primarily on looks. Also, if this assembler isn't always
available, you have to make enough inventory to handle orders that may come in
until he can make more if you don't have the time to do it yourself.

Volumes are uncertain, but the parts are cheap, so let's assume he buys enough
to make 100 units at a time. The selling price has to reflect the risk that
all those parts won't be used. Buy higher inventory levels and your parts cost
goes down, but risk of "dead stock" goes up.

Having a small electronics mfg business on the side, I live this on a daily
basis. Luckily I don't sell to price sensitive hobbyists :-)

But in the end, the price I'd try to sell it for has nothing to do with how
much it cost to build: it's cool looking. That's where the price comes from.

~~~
Natsu
Learning to solder mostly requires practice, so you could probably train
someone to do it. You just have to make sure they don't destroy a lot of
expensive parts learning. But you're right about all the other stuff.

I wouldn't be surprised to see something like this on Kickstarter, though.

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ortusdux
His site: [http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-
cm...](http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cmoy-
freeform-headphone.html)

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kragen
This 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/>

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.

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dimatura
This 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/photo...](http://www.flickr.com/photos/mohitbhoite/5708836052/in/photostream/)

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phodo
Does 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-
polyeste...](http://www.dickblick.com/products/castincraft-clear-polyester-
casting-resin/)

~~~
ratsbane
That's the shelf life for the uncured liquid. After it's been cured the
lifespan is almost forever.

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bcl
Depending on how hard you drive it heat dissipation may be an issue. It sure
looks nice though.

~~~
daeken
He wrote more about it and covered heat at
[http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-
cm...](http://runawaybrainz.blogspot.co.uk/2012/04/audio-crystal-cmoy-
freeform-headphone.html)

Seriously nice work. Tempted to build something similar myself.

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raverbashing
Beautiful!

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
Ever look inside an old tube amplifier? It's all point-to-point wiring, no
PCBs.

~~~
shabble
If 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>

~~~
mcguire
Oh, my. Why did you have to bring that up? And provide a link?

~~~
marchdown
Because that's beautiful, obscure and tangentially relevant?

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cake
Let'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.

~~~
bluesnowmonkey
I 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
Far fewer than that would know 1) which components are capacitors, 2) be able
to tell which capacitor was broken.

~~~
Natsu
A 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.

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kfury
Anyone 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
~10x that of still air. (from higher up in this thread)

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Someone
Very 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.

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muhfuhkuh
If 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>

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crikli
What'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.

~~~
andrewcooke
the 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.

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DanBC
There 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.

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joshontheweb
This would be a perfect Kickstarter project. I'd like one.

~~~
jonah
It might be more insightful to build one yourself.

~~~
joshontheweb
Not a bad suggestion. Seeing it build with discrete modules instead of a
circuit board make it seem like it wouldn't be that hard.

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zerostar07
Is that enameled copper wire or how does one solder on copper wire? Also, what
did he do exactly to avoid damaging the capacitors?

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RexRollman
Very cool. This made me realize that its been a long time since I visited the
Head-Fi forums.

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benihana
> _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?

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gouranga
I bet that is noisy as fuck. Long traces and no shielding - utter turd. Form
should never compromise function.

~~~
brohee
Yet 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
Just 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.

