Not your Grandpa's stereo: Plays vinyls, music over Wi-Fi, and classic arcade games

toddfx

Weaksauce
Joined
Mar 9, 2011
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October 2013 Update: PROJECT COMPLETE! View Page 2 for final images, AND visit audio.toddkumpf.com for a video and even more photos & info about each aspect of the project.


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(Original build log below)
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This has been in design and production for about 4 months, on and off, but i'm finally now with enough progress and momentum to warrant a proper work log.

It's a stereo/boombox that streams music over WiFi and also plays vinyl records. It has a built in music visualizer, an analog graphic EQ, and a few other tricks up it's sleeve. It's meant to be an all-in-one audio playing device with dynamic options for any music playing scenario. Here's a breakdown of it's features:

WHAT IT DOES:
01) Using a Raspberry Pi, streams music over WiFi from your mobile device (using ShairPort, functions like Apple AirPlay)
02) Has a built-in turntable to play vinyl records (parts adapted from a vintage Yamaha YP-D4)
03) Has four built in mid-range speakers, two tweeters, and one subwoofer (parts adapted from Klipsche ProMedia 2.1, with two additional speakers)
04) Has an analog graphic equalizer with 7 effective frequency bands (parts adapted from JVC SEA-10 vintage EQ)
05) Has a 5" CRT monitor that functions as an analog music visualizer, behaving similar to an oscilloscope
06) Can switch output from internal speakers to external device (via RCA cables)
07) Can also output wirelessly, transmitting over a medium which is still TBD. Will be either over WiFi using the Raspberry Pi, or to a specific FM band using a mini FM transmitter.
08) Can take auxiliary input from any device via 1/8" audio jack.
09) The Raspberry Pi can be switched into arcade mode, using AdvanceMAME emulator to play classic arcade games on the 5" CRT. Current functional games include PacMan, Asteroids, and Space Invaders using a custom USB controller pad.


The visual design is very heavily inspired by vintage HiFi equipment. Its housed in a wooden case, and has a brushed aluminum faceplate with heavy-duty switches and knobs.

Here's my 3D mockup of the physical design:
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I first began by collecting items i'd need.

Here's a first test using the Klipsche ProMedia stereo set, the JVC EQ, and the 5" CRT:
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I knew I wanted a visualizer for this project. I wasn't able to find any good looking software based visualizers that functioned on Raspian Wheezy (the default Raspberry Pi OS; I'm a Linux newb), but I happened upon this Instructables tutorial on how to turn a CRT monitor into an analog oscilloscope: [link]
Surprisingly, all it takes is a couple of wire snips. CRT monitors have two sets of wires that run to the tube: vertical coils and horizontal coils. The combination of the two produces the X/Y grid of pixels you see. To turn a cathode tube into a crude oscilloscope, all you do is connect the horizontal coil inputs to a generic speaker wire output. It really is as simple as that. The audio sent through the speaker wire will drive the horizonal coils to jump around depending on the frequency and volume, giving you a really mesmerizing visualization of your music.

Here's a video of the CRT oscilloscope visualizer in action: [photo will link out to vimeo video]


I also recorded a video showing waveforms as I play with an analog synthesizer (actually it's just the Moog Google Doodle): [vimeo video link]. In this video you also see the demonstration of how varying volumes effect the amplitude. For my stereo, I've fixed a potometer to the speaker wire input, offering an adjustment to the amplitude without compromising the volume output. This is useful because I found it can often be visually desirable to reduce the wave amplitude (i.e. spazzyness) in high volume scenarios.

A little bit more work and I have a working prototype of all the electronic components:
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Here's a closeup of the VU meters, purchased on ebay from Japan! There will be one for LEFT and one for RIGHT channels
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Now it's time to build the case. Like I said, it will be heavily inspired by vintage HiFi equipment like this Marantz amplifier, for example.

I live in the city of Chicago, so I'm limited to what I can accomplish in my 1BR apartment, with no outdoor space. My kitchen and my living room are my work spaces:
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Never the less, I use hand saws, hand files, a jig-saw, Dremel, and cordless drill, and old fashion engineering to make it happen little by little:
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For the top, which will be a hinged lid covering the record player, I wanted to give it a slight decorative touch. I found some Red Oak with a cool marble pattern in it, so I decided to use that as angled slice insets:
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Here it is all glued together:
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A mock-up of the case coming together: (please refer back to the [3D design image] for imaginative extrapolation purposes)
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For the front, I really wanted a nice brushed aluminum face-plate to house all the switches and stuff. Since I don't have access to a CNC or other mill equipment, I found this awesome internet resource BigBlueSaw.com which will take your CAD drawing (or Illustrator or other vector image) and cut it out of various materials for you including acrylic, aluminum, steel, wood, and leather.

I started by designing a faceplate in AutoCAD:
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I first had Big Blue Saw cut me a prototype out of acrylic so I could test fit my size and mounting holes (which I laid out using a ruler, my eye, and best judgement)
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For the speaker mounting, I didn't want tons of screw holes visible on the faceplate. I designed a double-pane system that lets the speakers mount to a hidden inner plate, which is then mounted to the front using only 4 screws instead of 8+.
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For the record player, I'm using the parts from this vintage Yamaha YP-D4. I specifically seeked out this model because I love the way the tone arm looks. I picked this one up on Craigslist for $50, as it is in pretty rough cosmetic shape. Mechanically though, all it needed was a cartridge + head-shell and it sounds amazing.

It turned out to bit a bit of a chore taking this thing apart. Yamaha used about 20 screws from both the top and bottom, AND glue. I hate glue.

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The inside. Really neat vintage electronics.
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Finally the guts separate from the shell.
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Now, for the new case, I just traced the cut-outs and mounting holes from the original directly onto the new ply.
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Cut it out using a jig-saw and hand drill, and here's the new base:
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All I have to do is re-assmble all the parts into the new case. Everything should work exactly as did before, including the mechanical tone-arm controls that rely on springs & levers.

Wow, now it's finally starting to look like something:
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After making some alignment and layout tweaks to my faceplate design, I sent away for it to be cut out of aluminum at BigBlueSaw.com. I'm very pleased with the result:
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And now for the most challenging part of the project yet...

Many vintage stereos feature etched faceplates. That is, the typography is actually engraved in the surface. It creates a unique look and spirit that I really wanted to embody here. At first it seemed like a crazy ambitious goal way out of my reach. However after discovering this thread about how to create your own custom etched metal panels, I realized it might just be in scope after-all. I researched various DIY solutions and landed on what's known as a "Saline Sulphate" etch. It's a relatively safe and simple (compared to the more acidic and electrically charged alternatives) etching process that uses a common chemical "copper sulphate" and salt solution to effectively etch aluminum.

Here's a brief rundown on the process:

Tools: Copper sulphate crystals (they're blue), salt, and all the blah-blah-safety stuff-blah-blah.
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I learned the specifics of the saline sulphate etching method through this site that lists a specific recipe. I scaled it up a bit, using a solution of:

+150g copper sulphate
+150g salt
+1,800ml hot water

First you design the graphics in Illustrator or whatever you please.
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Invert the colors and print it out 1:1 on glossy photo paper for laser printers. I found that the thinner, cheaper stuff works much better than the heavier weight you sometimes find in photo paper. Note that a laser printer is crucial; inkjet won't work.

The theory here is that you print the negative (and horizontal mirror) of the design on a laser printer, which uses a liquid polymer toner that's fused through heat. Using an iron, you can transfer your printed design onto the metal surface.

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I found that having my metal plate pre-cut with holes was a huge problem for the transfer of design from paper to plate. I ended up having to trim away all the excess, making sure no paper would hang over the edges. The overhangs would cause bubbling when transferring onto the plate, leading to major defects in the integrity of the graphics.

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Ironed onto the back of the metal plate:
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This particular piece is a new cover for the record player control pod.

After you iron on design onto the board, you mask off all the edges and extra space around the lettering. Any exposed metal will be eroded, so the idea is that you want to cover everything except for the parts you want to be etched.
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And here it is after etching and removing the tape. This was about 10 minutes spent soaking in the saline sulphate solution (copper sulphate + salt). The letters got a little too fat, so for the other pieces I ended up stopping the etch at 7 minutes which gave a much more refined result.
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If you want to see an early test (my first etch test), you can see how badly it turned it compared to this one. The background plate here etched for 30 minutes, which is what I read the norm was. Guess my mixture is a little stronger than that or something....

To get the black lettering effect I wanted, I filled in all the graphics with a generous amount of black enamel paint. It looks ugly here, but you have to imagine how it will look once the surface is sanded down. Everything will be returned to bare metal except for the etched bits.
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Sand down the surface and you get a rather nice looking etched panel:
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Going back a bit, here's some shots of the other metal pieces and other parts of the process:

After you iron the printed graphic toner onto the plate, it gets dunked in a bath of cold water. The paper soaks, allowing you to peel it away leaving only the toner adhered to the plate.
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And here it is in the saline sulphate etching solution. Bubbles rise from the exposed bits and it generates a brown, rust-like by product:
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Mounds of the byproduct protrude directly from the etching graphics:
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Wipe it down, peel off the tape, paint the graphics black, and sand the surface down and you get this:
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I was pretty happy with how these came out. It was my first time experimenting with etching, and know it won't be my last. It did take a bit of trial and error though.

I achieved the brushed aluminum finish using 60 grit sand paper, a sanding block, and a jig to keep the sanding motion perfectly parallel with the plate. It could probably use a bit deeper of a sanding, as there are still a few stray scratches that really stand out in certain lighting.

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NEXT STEPS:
01) Finish building wood case, and stain it.
02) Once case is stained, install faceplates and begin mounting components.
03) Fabricate internal brackets and standoffs for all the various components that need to be secured
04) Wire everything together.
 
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Great idea! :D
And the execution is going quite impressive, especially considering you are doing all this in your apartment.
And I learned about etching...added bonus. Keep up the good work.
 
Absolutely amazing. This has to be one of the most unique things I have seen created . . . you skill is very evident :)

I had no idea etching could be done that way . . . well done.

Cheers

Fen
 
very cool project, and incredible work on the etching. that looks like something that could go wrong a million different ways, and how well it turned out is a testament to your craftsmanship. keep it up!
 
One of the best idea's i've ever seen in this section can't wait to see the finished result
 
YES! Progress! Finally it's taking shape. This weekend I set a goal to do a test fit of all electrical components, making as many of them permanent as possible. There's a ton of wiring I need to do, for all the front switches and such, so the sooner I can get everything mounted permanently in the case, the better.

Starting with the speakers, I decided to change up my mounting method. In the previous post, you can see the double-pane solution I was trying. The acrylic was too flexible for stability and I was having a difficult time getting the speakers flush enough. They ended up being set back about a quarter inch from the front panel, so it left a quite noticeable gap.

I simplified everything by just attaching mounting posts directly to the back of the faceplate. I drilled a shallow hole for each mounting location, then used J.B. Weld to secure the posts. I'm confident it'll be strong enough, J.B. Weld epoxy hasn't failed me yet!
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Here's the front with 2 speakers using the new mounting method, and also the VU meters mocked up in place!
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The EQ is also installed, which I had to chop up a bit to squeeze in...
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Subwoofer is in! I can't wait to hear how it resonates in this case.
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Sub also gets a mesh grill, which is the original one from the Klipsche set that the sub, speakers, and core amp came from. In this picture you can also see that I covered the feet with...electrical tape. I'm eventually going to put some felt on the base of the feet, but until then this will keep the exposed screws from scratching up my tables (any more).
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The amplifier is mounted. It's raised up on stilts like this because wires need to plug into the bottom of it. The bolts drill through from the bottom of the case, secured with a nut at the base. Another layer of nuts acts as the platform for the amp's metal plate to rest on, followed by a third nut to secure it into place. All non-removable nuts are thread locked.
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As for the electronics, I started with the Raspberry Pi. I'm using 9/16" 6-32 standoffs for all the mounting posts. Luckily most electronic circuits have mounting holes pre-drilled, so it makes it super easy to get this stuff into place. Trimming those wires was quite a bit more time consuming though. I'm doing it up right though, with solder and heat shrink tubing. Still working on perfecting my technique though I'll admit!

In this pic you see the Raspberry Pi, the USB hub, and the USB hub's power AC adapter. The two red wires dangling from the USB hub will be the Pi's power switch (one of the two "PWR" switches in the lower left of the faceplate). The two dangling wires from the AC adapter are the actual hot lead + GND that will be wired directly into the power strip along with all the other electronics that would normally plug into a wall outlet.
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Aaand here's everything.
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Here's a brief breakdown of the components installed. The only additional items that aren't pictured are the Klipsche volume/subwoofer controller (which will be mounted in the center of the top faceplate, between the two sets of speakers), and the AC adapters for the CRT & the pre-amp. They'll be in the empty space over by the phono pre-amp. And then of course the record player its self which is attached to the removable platform.

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Keep in mind nothing is actually wired together yet. For wiring, i'm going to do something a little interesting and use this vintage styled braided cord I got on ebay:
Like I said, hopefully my heat shrink technique will improve as I go on! This is the power switch for the CRT monitor.
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The CRT and the EQ are not perma-mounted yet. The EQ is perma-attached to the front faceplate, and so will the CRT once I get to that point. I need to solve some wiring challenges on the CRT before I do that though. I need to hi-jack the CRT circuit's onboard brightness control with my own potentiometer, as well as one of the input selection switches.

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Those four pegs on the inside of the case, near the top, are where the removable turntable platform rests.

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Please ignore the gaps between some of the pieces, nothing is secured in these pics, just mocked up! When all the bolts are tightened down, everything should line up nicely.
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There's still one piece missing from the lid; a strip that covers the speaker section.
Here's the record player lid though, which will be hinged from the back, lifting up to reveal the record player.
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(lid slid forward just for reference)
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The lighting is really terrible in these iPhone photos. Next time I'll post some better, naturally lit, properly white balanced photos of the true color of the wood case.

Staining the case has been a big hurdle to get over. I'm not that great with finishing wood, and I have a really hard time choosing a favorite stain. Coming from a digital art background, I'm used to having complete control over the look of the outcome. But with wood stains, it's sort of an all or nothing kind of thing in my experience. Sure you can let it soak in longer for varying shades, but 80% of the magic happens the instant you apply it. So you're kind of just stuck with whatever comes out of the can. I don't know, i'm sure there's more of an art to it, but I haven't learnt those skills yet.

Anyway, after doing some stain tests last week, I settled on a subtle, natural look for all of the exterior Red Oak slabs. That's paired with a slightly darker, more burned shade for the few pieces of Birch (the front "shelf" strip, the turntable mount, and the rear panel). After testing various stains, I decided I liked a more classic natural look.

NEXT STEPS:
01) Solve some wiring issues with the CRT.
02) Get the CRT and lower faceplate personalty mounted, and install the last few components.
03) Drill holes and install rear I/O ports: two USB, HDMI, 1/8" audio output and 1/8" audio input
04) Wire all the front panel switches and get all internal components wired for audio
05) Create and wire custom power strip (which goes in the open space at the very back of the space)

Lots to do....
Really eager to get this thing playing some music though, so I'm cranking on all cylinders.
 
That is looking really great! I wish there was a way I could hear it play! Youtube won't do it a lick of justice, I'm sure. Though, you'll have to do a video and post it here so we can see all of it in action, dials moving, tabling spinning, CRT wirbling ;)
 
Just a couple of pics of the completed and functional turntable:

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Testing, hooked up to ye 'ol Yamaha CA-2010.

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And here's a sneak peek of what all the power cords will look like. The power strip for all 6 of the powered devices is exposed at the back of the case. I'm replacing all the standard power plugs with these old looking plugs and cloth wrapped cords. Plugs came from Home Depot where they were shiny and new. I sanded them down, soaked them in hydrogen peroxide (an aluminum oxidant), and smudged some black paint on them to make them look a bit worn.

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I really look forward to your updates. Great idea and execution. :)

It was like walking back in time to see a Grado cartridge on a turntable. I remember their marketing, or rather lack of marketng - so good that they don't need to advertise.
 
Are you not worried about the speakers rattling the tone-arm? Or did you somehow isolate the turntable?

Awesome job. :D
 
Are you not worried about the speakers rattling the tone-arm? Or did you somehow isolate the turntable?

Awesome job. :D

Hah well that is indeed a concern, but I did a test in the very beginning with the record player literally sitting on top of the subwoofer, along with multiple speakers surrounding it, and it seemed ok. Hopefully that holds true through to the final assembly.

The sub has an independent volume control, so there's that too at least.
 
Borrowed a Canon 5D from work this weekend and took some shots of the progress. These are mostly just beauty shots, rather than documentation of new progress. A few new shots though.

Got pretty much everything wired up: all the input and output switches are good to go, and built the back I/O panel.

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Notice the servo attached to one of the knobs on the CRT. More on that later!
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I was planning on getting to a powered test state tonight, but a snafu with the speaker faceplate (a J.B. Weld bond FAILED (for the first time ever)) set things back a day or two. The speaker faceplate also holds the volume circuit, which is a pivotal piece in regards to the Klipsche amplifier. The whole thing is pretty useless without it, and its installation is a pre-requisite for a handful of other pieces. So until I can re-engineer a mounting method, this is where she stands. Hopefully after work in the next couple days I can get it sorted out.
 
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Nice!!
I suggest giving the back I/O panel the same aging treatment as the power plugs.
 
The back I/O panel should be made from brass. :)
Fantastic work; thanks for the explanation of etching.
 
The vibrations from the speakers is going to certainly be a problem for the record player as there is absolutely no dampening via the turntable legs as it would normally be. Since the turntable is directly mounted to the same wooden frame the speakers will be... I don't think this will be a good system to play records on.
 
The vibrations from the speakers is going to certainly be a problem for the record player

That was absolutely my first thought when I saw the project. Will be interesting to see how you overcome that. Awesome project.
 
I definitely hear you guys in regards to the vibrations. That thought has certainly been in my mind. In a couple days time I'll be doing the first fully powered test. I'm prepared to modify the turntable mounting with some kind of vibration resistant feet, and/or installing some kind of sound dampening insulation beneath the turntable.
 
Sorry for the massive delay. The project is finished now!

I recommend visiting audio.toddkumpf.com for higher res and many more photos & info, but here are some selects below. There's also a video of it in action on the site.

I guess the wood is thick and sturdy enough to absorb most of the vibration, because there actually isn't any audible distortion (to me anyway) in the record player, unless the bass is really cranked up.

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Please visit audio.toddkumpf.com for more photos, information, and a video!
 
Excellent build toddfx.

I love the crt and the way you done the etching, it has come extremely well.

I wish I had similar skills, unless its a kit and has easy instructions I cant build for shit.

Bravo :)
 
Well done! Also, congratulations on making Hack A Day last week.

This has given me a great idea for integrating my Klipsch ProMedia into my desk/Monitor stand.

(I just so happen to also have a 50# bag of Copper Sulphate we use to keep tree roots from clogging up our sewer lateral. Looks like I have another project this winter.)
 
Old thread, but idea and execution is super awesome, and inspiring! Thanks!
 
Wow, never seen this one...

Nice work!
 
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