Okay folks, in this tutorial I’m gonna show you how to make an ultra-portable, mini, digital boombox (sans speakers).

The idea here is that you can very easily carry this (boombox) around and connect it up to any set of speakers and a digital source such as a tablet, smartphone, Raspberry Pi (running XBMC or Squeezeplug), and enjoy quality music, where-ever, when-ever.

What you should end up with is a mini boombox similar to the one in the picture below – the black box, that is. Okay, I know! You can’t really call it a boombox (since it doesn’t have any speakers attached to it), but the great thing is that you can pair it up with any speakers you have lying around.

Notice that I have both my smartphone as well as a Raspberry Pi (in the picture above) and this is only because I’m using the smartphone as a Squeezeplug remote to control the music. I could very well have had only my phone connected to the Lepai amp (which means I’d only require the setup shown below), and I’d be able to play the songs off of my phone/USB storage device(s).

Also note that even though I have my Sansui receiver (in the first picture above), it’s not really a requirement for this project – since the mini boombox has it’s own mini amplifier, the wonderful Lepai Tripath TA-2020A+. That being said, I do prefer to hear my music through the Sansui receiver (at least while I’m listening at home).

The sound of this setup is so mind-blowingly awesome that it will blow your mind (duh!). Yep, for some reason this setup sounds way, way better than even my basement setup, which includes a tube-based setup of a vintage Heathkit power-amp, and a vintage Dynaco pre-amp, connected to a pair of vintage Wharfedale speakers (with 10″ woofers).

Oh, by the way (and in case you may be wondering), the speakers that I have connected to my Sansui receiver are JBL’s (with 8″ woofers).

This mini-boombox has now gone on to both encase the Lepai amplifier, as well as enclose the components contained within the shelves of the mini audio-racks shown in this project of mine. I much prefer this concealed look, as compared to the exposed look of the earlier project.

Building your own Mini-Boombox

All right, so let’s get down to the business of showing you how to build this mini-boombox for yourself.

Things you’ll need

• [A] – Rectangular Wooden Box – Available at Dollarama (Canada) for $3, and sold as a set of 3 nested boxes
• [B] & [C] – Lepai Tripath TA-2020A+ Amplifier with Power Supply
• [D], [E] & [F] – Self-powered USB Hub with USB Cable and Power Supply
• [G] – RCA Audio Cables (Optional – only if using a separate amp/receiver)
• [H] – Mini-Audio Stereo to RCA Audio Cable
• [I] – Mini-Audio Stereo Cable
• [J] & [K] – USB Hard Drive with USB Cable (Optional)
• [L] – Behringer UFO-202 DAC (Digital-To-Analog-Converter)
• [M] – Raspberry Pi with USB Cable (optional)
• All-thread Rods
• 8 Nos. Regular Nuts to fit all-thread rod
• 4 Nos. Acorn Nuts to fit all-thread rod
• 4 Nos. Super Strong, Rare-Earth Magnets 1/4 inch
• Drill with various size Bits
• Dremel or similar Rotary Tool with a variety of bits

Cutting-out the box – Front Face

To start off, put your Lepai amplifier into the box and center it as accurately as possible. Then hold it steady and take measurements for the height and width. Once you have those measurements, use a pencil and draw the rectangular shape on the outside front face of the box. Then take your rotary tool and start cutting out the rectangle by using an appropriate cutting bit. After the rectangle is cut, remember to cut two quarter inch slits towards the bottom, on either side of the amplifier (shown circled red in the picture below). This is required in order for the amplifier to be pushed outwards slightly, so that it stays flush with the outside face of the wooden box.

Cutting-out the box – Rear Face

With the amplifier still held firmly in place (inside the box), bring it to eye-level and use your pencil to mark cut-outs for the following (going from left to right, top to bottom):

• Behringer UFO-202 DAC (take measurements if required)
• Other Wires which require external connections
• RCA Inputs (Right and Left)
• MP3 Input
• Speaker Wires (Right Channel)
• Speaker Wires (Left Channel)
• Power Supply (Lepai Amplifier)

With that done, you will now need to drill four holes in each inside bottom corner of the box. These holes will be used in order to secure four all-thread rods in place, and the all-thread rods are (in-turn) used for the following two purposes:

1. To provide feet for the mini-boombox
2. To provide a means to secure the lid to the box (using magnets), while still allowing easy access to the components insde

The picture below shows the circled all-thread rods (in the black-box) and the super-strong, rare-earth magnets (glued to each corner of the lid).

With all of the cut-outs completed, you may now go ahead and paint (or stain, if that’s what you prefer) your mini-boombox. I chose to paint it a dull black in order to both conceal all pencil markings, as well as to not show any brush/roller imperfections (which tends to show easily with glossy paint or stain).

Putting things together

Once the paint/stain has dried, you may proceed to secure the amplifier to the inside of the box by means of four screws. After securing the amplifier in place, go ahead and insert the DAC into its rectangular slot at the rear. With that in place you will now want to drop in your hard drive, and ensure that it sits flush with the top of the amplifier. This will allow for your powered USB hub (which goes in next) to just about reach the top of your box (assuming you’re using the same one as I did), and allow for the lid to close evenly.

Now, ensure that the USB cables for both your hard drive, as well as the DAC remain inside the box, since they need to be connected to the powered USB hub. The only USB cable that should exit out of the box (via the rear top-right opening) is the one from the USB hub, and it will end up in one of the USB ports of your Raspberry Pi (if you’re using one).

The above being said, there may be times when you would want to attach the hard drive directly to your phone (assuming it’s a rooted android phone which supports USB-OTG), in order to access the 100’s of gigabytes of music you might have on the drive. That’s when you will want to have the hard drives’ USB cable exit out the rear opening, in order to attach it to your USB-OTG cable.

Needless to say, the power supply for the USB hub must also exit the box, in order to connect to your power source and provide power to the hub.

Now, let’s show you how all of these components are laid out inside the black box. Okay, first off, the amplifier is screwed down to the bottom of the box. The next component you want to put in place is the DAC, and ensure that it’s held securely in the opening. Once that’s installed, you then want to lay down your hard drive over the top of the amplifier, and to the front of your DAC. Remember to keep the USB cables of both the DAC as well as the hard drive inside the box, since they connect up to the USB ports of your powerd USB hub. Next up is the USB hub, which is laid on top of the hard drive, towards the front of the box. The USB cable of the hub must exit out the box (if you’re connecting it to a Raspberry Pi), as must the power supply cable.

The following two pictures show you a front and rear view of how things are laid out internally.

Now, if (like myself) you have a Raspberry Pi (with SqueezePlug installed on it) you could very well pair that up with this mini-boombox that we’re building, and then connect the two to your favourite speakers and you’re good to go. If you decide to go that route, you will have a setup similar to the one in the picture below.

Here once again is how my setup looks, without my floor-standing speakers in the picture though.

And, how about sitting back and enjoying my setup in action (in the following video)?:

Okay, so what are you waiting for? Go ahead and build yourself one of these little puppies, and let me know how it went.

If you do anything better/different, do let me know about that as well.

I’m sure at least some of you will have better tools, skills and experience in painting, woodworking or machining, and that will most certainly help you end up with a much better looking product than mine. Hopefully we can all benefit from each others’ experiences and results.

Cyril Rose

This tutorial is almost identical to my other one – http://cyrilrose.com/?p=214, the only difference being that I’m now using a smaller set of main speakers (Realistic Minimus 7) – see picture below – which in turn makes this setup a lot lighter and therefore more portable.

Needless to say, the sound quality of this setup is not as rich and full as v1 (Bose AM-3 setup), due to the fact that the Minimus 7’s only have a 4″ bass driver. Ultimately it comes down to what you’d much rather prefer: more portability (while compromising sound quality), or better sound quality (while compromising portability). Of course, it’s nice to build and have both versions lying around so that you could chose which one you want to use depending on the situation.

I’ve now put on my “thinking cap” (and gone back to the drawing board) to figure out how I can improve on v2 such that I make it lighter, while also allowing for the main speakers to be easily and quickly moved further apart for a better/bigger sound-stage and therefore a better listening experience.

In this post I’ll show you how to setup a somewhat-portable, open-style boombox which (to say the least) will “blow-your-brains” (as well as that of your friends and neighbours).

As the saying goes, “a picture speaks a thousand words”, so here’s what you’re trying to achieve:

Assumptions/Prerequisites:

In this tutorial I’m assuming that you already have a Raspberry Pi configured and up-and-running (in wireless mode), and that the operating system installed is Raspbian Wheezy.

Before starting, I must say that while working on projects such as this, I normally take pictures of every step I perform (so that I’m able to make it easier for you to understand/follow), but since I was in a hurry to complete this project (had to get it ready for a backyard party in a very short time) I couldn’t afford to spend the time clicking pictures. That being said, I will still try to make it as simple and easy to understand as possible, whilst using just text.

This is a late edit: I was able to create a new mini-rack (using hobby Poplar wood instead of MDF) for my R-Pi stack, and for the new project I was able to click pictures along the way (more or less). You may want to read and/or complete that project before you get to this one, since it will give you a better idea of how to put together the “DIY Flexy Rack”, which is required for this project as well.

With that out of the way, let’s get to work, shall we?

Things you’ll need, in no particular order:

• 1 Raspberry Pi, along with the following:
• 1 Power Adapter for Raspberry Pi
• 1 Case for Raspberry Pi – I made my own case using a Dollar store wooden box (crafts section)
• 1 SD Card – preferably 4GB or more
• 1 WiFi Dongle – I use the TP-Link TL-WN725N
• 2 Full-Size All-thread Rod(s)
• 12 Regular Nuts (thread size suitable for all-thread rod above)
• 4 Acorn Nuts (— as above —)
• 4 Arrow Heads (with threads)
• 1 Plank of 1/4 inch MDF (or other wood of your choice – balsa would be great, but MDF is the least resonant and therefore most ideal, IMHO)
• 1 Powered USB Hub – The smaller the better; 4 port should suffice, though mine has 7 ports
• 1 DAC (Digital-to-Analog Converter) – I used the Berhinger U-Phono UFO202
• 1 USB Pocket Drive – I used the aData NH92
• 1 Mini Stereo Amplifier – I used the Lepai Class-T Mini Stereo Digital Amplifier LP-2020A+
• 1 set RCA Interconnects
• 1 Power Extension Box
• 2 Screws for Power Extension Box (Screw head must be small enough to go through the wider portion of extension box hole – on rear side – but large enough to not fit through the narrowest portion of the hole)
• 1 Satellite-style speaker system (with Bass module) – I used my 25 year old Bose AM-3’s
• CAT5 Computer Network Cable (preferably the Plenum variety i.e. with teflon-coated, solid-core copper wires)
• 1 set Speaker Stands (optional)
• 2 Pairs of Metal “L” Brackets – Reduce to 1 pair, if not using optional speaker stands above
• Nuts & Bolts (to attach satellite speakers to the “L” brackets of speaker stands and the top MDF board)
• 4 Particle-board Screws (to fasten the very-light Lepai amplifier to the top MDF board – check that screw head is wide enough to hold down the amp, and that the threaded portion is narrow enough to fit into the amp’s 4 securing slots)
• Android Phone and/or Netbook/Laptop and/or Tablet (to control your Squeezeplug/Logitech Media Server)
• 1 Can of Primer
• 1 Can of Flat Black Paint
• 1 Paint Tray
• Paint Brushes/Rollers
• Fine Wood Sandpaper (220 grit)
• Drill
• Drill Press
• Measuring Tape
• Metal Hacksaw
• Metal File

Here’s a picture showing some (not all) of the above parts (click picture to enlarge):

Software Installation and Assembly Instructions:

Dessert first: Tackling the Raspberry Pi

First things first – ensure that your R-Pi is enclosed in its case, so that there’s no risk of it getting damaged/shorted.

Now, with your R-Pi powered off, the next thing you want to do is to connect your powered USB hub to the lower USB port of your R-Pi, and then connect your WiFi dongle to the port above. Note that the WiFi dongle could also be connected to the USB hub (rather than to the R-Pi), which means that the one and only USB device you need connected to your R-Pi is the powered USB hub.

Next, you want to ensure that you connect the following to your powered USB hub:

• Keyboard and Mouse (or dongle for wireless keyboard/mouse) – optional
• USB Hard Drive – optional
• DAC
• WiFi dongle (if you’ve not connected it directly to your R-Pi’s USB port)

Once that’s done, you may connect the power adapters for your R-Pi and the USB hub to your power extension box.

Give the R-Pi a few moments to start up, and once it’s up, you may proceed to login. Once logged-in you will want to launch a terminal window and issue the following commands:

Building the large Shelving System aka “DIY Flexy Rack”:

The large shelving system is used for the purpose of housing both the bass module of your satellite speaker system, as well as the amplifier, the Raspberry Pi stack, and the satellite speakers.

Okay, so let’s begin. From your (large) sheet of MDF, cut two planks that are slight larger than the size of your bass module. This is because you will need space at the back to house the power extension box, as can be seen below:

The next thing you want to do is to give each plank of MDF two coats of primer, sanding in between each coat, as well as after the last coat. Ensure that you sand both faces as well as all four sides.

Once your MDF surfaces are well primed and dry, you will want to start applying the flat black paint. Again, you’ll need to apply at least two coats of black paint, and also ensure that you lightly sand between each coat, as well as after the final coat.

Now it’s time to mark and drill out the required holes. Start off by marking the four corner holes. You only need to mark these holes on one of the racks, since you will now stack one on top of the other (ensuring that they are well-aligned on all sides) and they clamp them down to your workbench and drill the four holes through-and-through using your drill press. Ensure that you use a drill bit that’s slightly wider than the width of your all-thread rod.

You will now want to drill four pilot holes in the corners of the rack that will be as the lower rack. These four holes will be used for the four arrow heads, so again, ensure that the drill bit used is not wider than the width of the threaded portion of your arrow heads. Also ensure that these holes are not drilled through-and-through, but rather just to the depth of the threads.

Once those holes are drilled, you will want to mark holes for your amplifier and satellite speakers. This is to be done on the rack that will be used for the top, so ensure that you set aside the bottom rack (the one on which you drilled four pilot holes in the four corners), so that you don’t end us using that one to drill these holes on. Place your amplifier towards the center of the rack (take measurements if you’re a perfectionist like me) and mark the four spots where the amplifier has slots for securing down. Also place the “L” brackets (either towards the front or rear of your rack) and mark the two holes for each of the two brackets. Now, take your top rack and secure it to your workbench and drill the holes you just marked. Note that you will need to drill pilot holes (of the appropriate width) for the amplifier slots, and wider holes (through-and-through) for the speakers’ “L” brackets.

Now it’s time to cut the all-thread rods to size. Place your lower rack on a table/work-bench and then place your speakers’ bass module on top of the lower rack. Next place the upper rack on top of the bass module and use your measuring tape to measure the height (from top to bottom). Ensure that you add a quarter inch each for both the top and bottom, to allow for regular nuts to be used towards the bottom of the lower rack and acorn nuts to be used towards the top of the upper rack. Once you have that measurement (with the half inch added), use it to cut out four pieces of all-thread rods (using a metal hacksaw). Using your metal file you may want to file the edges of the cut side, to allow for the nuts to be threaded on easily. At this stage you also want to mark two (or more) holes that will allow for securing your power extension box. Take measurements of the holes in your power extension box and ensure that you mark and drill pilot holes appropriately on the top/upper face of your lower rack, behind the bass module. Screw on (only half-way) the appropriate screws.

Grab hold of your bottom rack, flip up over so that the bottom side faces up and screw in the four arrow heads. Make sure you screw it in all the way (till you’re no longer able to see any of the threads). Flip the rack over so that the arrow heads are now in contact with your table/workbench. Put the four all-thread rods into the corner holes and screw on four regular nuts towards the bottom face of the lower rack (where the arrow heads are). Then screw on four more regular nuts towards the top portion of the lower rack. Screw on four more regular nuts, and let them go down about an inch or two (from the very top). Place your bass module on top of your lower rack and then place the upper rack on top of your bass module, ensuring that the all-thread rods go into each of the four corner holes. Once you’re able to see the four protruding all-thread rods, screw on the four acorn nuts. Finally, tighten (screwing upwards) the regular nuts which are towards the bottom face of the upper rack.

With that done, you can now screw down your amplifier, and the two “L” brackets. You may also attach your satellite speakers to the two “L” brackets, and your power extension box to the appropriate screws, behind the bass module.

At this stage, you’ve got your main/larger rack ready, so it’s time to build the smaller rack (which will house the R-Pi and other peripherals).

The idea of the smaller rack (being stand-alone and removable) is that I want to be able to quickly and easily move my R-Pi (with attached peripherals) from the portable setup to my main audio setup (containing floor-standing speakers, tube amp’s, high-end power cables and interconnects etc.) and have my streamed music play on my super-duper-mind-blowing system. When such a move is required, all I have to do is, (a) unplug the Lepai amp’s power adapter, (b) detach the power extension box (from the lower rack), and (c) lift the mini-rack, along with the power extension box and move it to my main rig.

So, without further ado, let’s get down to building the mini-rack, shall we?

Building the Mini-Rack aka “DIY Flexy Rack”:

In order to keep the length of this post more manageable (readable), I created a separate post which details the procedures for building and assembling the mini-rack, to contain your R-Pi stack.

I hear you ask, “How does it sound”?

“Mind Blowing” is all I can say, and that says it all!

You really have to hear it to believe! So what are you waiting for? Go ahead and build yourself one, and let me know how it went.

If you do anything better/different, do let me know about that as well. I’m sure at least some of you will have better tools, skills and experience in painting, woodworking or machining, and that will most certainly help you end up with a much better looking product than mine. Hopefully we can all benefit from your experiences and results.

Cyril Rose