|The wooden ghettoblaster case ready to
receive its audio equipment
In case you missed it, you can find here the first steps. I used marquetry techniques to give this ghettoblaster a retro look. I did not want to build yet another box with an amp and speakers (where would be the fun in that?).
I had old 3 way car speakers lying around. These are meant to be flush mounted. If you're familiar with building speakers, reading on might make you scream (you've been warned).
Googling around, I discovered a little of the science behind building speakers and lots of people arguing about technicalities (as always). I'm therefore not going to start a debate here...
here is an interesting source of information if you want to push your education about this topic a little further...
|Speakers are now ready to be
|Using a router to flush mount the car speakers
Here is (in very short) what I discovered about speakers: home audio is usually made of ported speakers where the driver (the thing producing sounds) is mounted in a box with a hole in it. If done right, it will sound great and will make your speaker much more efficient. It also requires more room (which is not a problem at home). Car audio speakers are however meant to be flush mounted either on the parcel shelf (large to infinite space called infinite baffle) or in very tight spaces such as car doors. These speakers ('drivers') are much more forgiving and should accept most box designs. I'm happy this is my case (car audio speakers) as I won't have (and don't want to) make all the calculations. This is as far as I'll go in this post and will go over audio in another one later.
|Speakers can now be flush mounted
Adding VU meters
VU meters - Woodwork
We're not going to talk about electronics here, we will focus on the physical integration of the VU meters I purchased from eBay.
|This is what I'm going to add to the front panel
These VU meters are cheap plastic Chinese meters I got are supposed to be flush mounted and need to be attached from underneath the wood. The result above is the trickiest part of this project (see how thin the wooden edges are?). To give you an idea, the whole thing is 4cm high (about 1.5 inch).
|VU meters front panel
drying in the vice
|VU meters selecting and marking
the right spot
|Cutting the opening with a jigsaw
If you're like me ... it never fits the first time you try:
|The opening is a little too small,
I'll have to enlarge it with a file
Filing is always a little tricky: Remember to make an angle (front face needs to be the largest) so it is easy to insert your piece of wood. Depending on your needs, you can file the insert, the opening or both:
|Filing the (VU) insert with an angle
to be easy to insert it in the opening
|Front view after adding a little wood filler and
sanding off the excess filler and wood to make it perfectly flat
Et voilà !
|Front face finished and ready to add the VU meters and
power light (where does that hole on the right come from? ;-)
Glueing VU meters: to do this I used only a little (hot) little glue so the VU meters can be removed if needed and leds can be added for backlight. Remember to put it on an even surface to have your meters at the same level as the front panel:
|VU meters glued to the panel
|Original idea as backlight
for the VU meters
VU meters - LightsI want my wooden ghettoblaster to look good even at night and to be able to see the needles dancing as I'm blasting music around.
My first idea was to use bright white leds (in series with a resistor). Out of the three I had only two worked, they were cool white (therefore not so cool ;-) and they were a little bulky so I decided to use SMD leds from a broken (warm white) led bulb. I strongly recommend always keeping a broken led bulb handy, they're a gold mine for leds.
|Unsoldering leds from a broken bulb
|4 warm white SMD leds wired in parallel
with only one resistor for a 12V supply
|VU meters with a warm white backlight
on my Wooden Ghettoblaster
I'll have a limited number of controls:
- A volume control, connected with a shaft to the volume potentiometer of the amplifier
- A USB charging port
- Two line-in/line-out/headphone 3.5 jacks wired in parallel
- A power switch (230V) for the power supply
Since the volume control is the only one coming with a real challenge, we'll focus on that one.
I started by inserting my 'The Crunch' amplifier (from 1992 !) in the box to find the precise place where I'll have to drill the hole for the volume control shaft.
|The amplifier in the casing
(to align the volume buttons)
|My DIY volume control extension
The wooden ghettoblaster (box) with its volume control (I added the speakers for the photo):
|The wooden ghettoblaster
with its volume control
Adding a handle is not as easy as it seems... you need to combine both metal and woodworking techniques and need to be precise with both.
Building the handle
I chose a 16mm square iron tube. I wanted it square and wanted iron because I wanted to solder it (with my soldering machine) and wanted it to rust.
This part is straightforward but needs precision. You need to cut your tube at a perfect 45° angle... and I always manage to screw that up but eventually always file my way through it (this is annoying to get the correct length). The pictures below are before and after:
Taking pictures while soldering is difficult so I didn't do it: you'll have to believe me when I say I did it myself ;-) I however managed to make holes in my handle by accident. This happens when you're terrible at soldering (which is my case). Anyway it does not matter since I want it to be imperfect and rusted.
To let it rust, I had to remove all the coating it with a metallic brush
|Removing the coating with a metallic
|My handle rusting on the
Adding a groove to the sides to insert the handle
I'm taking a shortcut here and skip the part where I build the box, there's nothing special there. We're going to add the handle and to do that I'll make 10m long grooves on each side with my router to slide the handle in.
And made the groove:
|The mark where the handle will come
|The freshly cut groove in the boombox
|My wooden ghettoblaster box with
the rusted handle on
You can read my following posts where I take care of the audio and electric parts as well as paint these speakers (fake rust, ongoing).