Speaker box build

[thomasha]

Hi, this is not a guitar amp, but I guess it's inspired by some pretty wooden tube amps from Vox.
There are not that much builds of this kind here, but a small amp is sometimes necessary when debugging new circuits to work with a sound probe.

The ideia was to build a bluetooth speaker in a wooden enclosure.
Much preattier than the available rubber like finishes usually used for this stuff.
On the other hand, I always need a small amp to probe my builds, so a jack input was a must. The fact that this runs on a rechargeable battery makes things easier. I already have a small amp running on batteries, but everytime I forget to turn it off it wastes a whole 9v battery!

Back to the build, I started from a solid piece of wood and shaped it and carved, so there are no joints visible. That gives a nice back, where the passive speaker is located. Fortunatelly I recently got a rotary tool, that helped a lot in the carving and sanding. I still had some piping and grill cloth from some previous amp builds, which helped a lot hiding some mistakes at the line between the baffle and the carved cab.
The final product looks like this:




There were a lot of problems in this build...
Keep noise out of tube amps has no comparison with what the guys from wireless systems have to deal with.
All the clicking and high pitch noise emitted is captured by parts of this circuit.
And it just has a bluetooth module and a small class D power amp. The main problem is that everything is inside the same enclosure, tightly packed together.
After complaining a lot because of the lack of proper schematics I managed to find the chip's datasheet with some application notes, which really helped. Much better than the layouts made using paint. There are some necessary connections to the chip to work, and some extra things to keep in mind if you want it to be silent.

I'm really glad that it works! Hope you like it!

[cooder]

Pretty darn cool! 

[woolie]

Hi, this is not a guitar amp, but I guess it's inspired by some pretty wooden tube amps from Vox.
There are not that much builds of this kind here, but a small amp is sometimes necessary when debugging new circuits to work with a sound probe.

The ideia was to build a bluetooth speaker in a wooden enclosure.
Much preattier than the available rubber like finishes usually used for this stuff.
On the other hand, I always need a small amp to probe my builds, so a jack input was a must. The fact that this runs on a rechargeable battery makes things easier. I already have a small amp running on batteries, but everytime I forget to turn it off it wastes a whole 9v battery!

Back to the build, I started from a solid piece of wood and shaped it and carved, so there are no joints visible. That gives a nice back, where the passive speaker is located. Fortunatelly I recently got a rotary tool, that helped a lot in the carving and sanding. I still had some piping and grill cloth from some previous amp builds, which helped a lot hiding some mistakes at the line between the baffle and the carved cab.
The final product looks like this:




There were a lot of problems in this build...
Keep noise out of tube amps has no comparison with what the guys from wireless systems have to deal with.
All the clicking and high pitch noise emitted is captured by parts of this circuit.
And it just has a bluetooth module and a small class D power amp. The main problem is that everything is inside the same enclosure, tightly packed together.
After complaining a lot because of the lack of proper schematics I managed to find the chip's datasheet with some application notes, which really helped. Much better than the layouts made using paint. There are some necessary connections to the chip to work, and some extra things to keep in mind if you want it to be silent.

I'm really glad that it works! Hope you like it!

Would you be interested in sharing the appnotes and data sheets? I' been meaning to do something similar.


W.


Sent from my iPad using Tapatalk Pro

[thomasha]

I used the CSR8635 chip, here you can find the datasheet:
http://electrothing.co.za/images/products/bluetooth-audio-module-8/CSR8635-datasheet.pdf

it doesn't work if you don't use a voltage divider between the 3.3v pin, Vreg pin and ground. Vreg pin needs a 1.8v logic to start the chip. I had to read a lot of threads just to find it in the datasheet...

If you can, go for the CSR8645. It's an improved version, and there is already a good schematic for a complete board here: http://g01.s.alicdn.com/kf/HTB11F5VFVXXXXbxXXXXq6xXFXXXj/220726009/HTB11F5VFVXXXXbxXXXXq6xXFXXXj.jpg

If you can find a board with a power amp, go for it. It's really difficult to solder the module without some good glasses.

If you want to use your own power amp, choose one with a differential input. It helps a lot to reduce the noise. I had really short pins connecting the chip to a shielded cable and still was picking up some clicking, like when the chip is not playing any music.

To avoid ground loops a small 5v to 5v isolated dc/dc converter is a must.

[verr76]

Beautiful enclosure.

I've been thinking of building something similar but using a class D amp (50 - 60 ish watt) amp. Adding also some sort or preamp. Quite fond of the ROG tonemender. Any advise on those prebuilt class Ds?

[Thomas_H]

Compliments on completing this task!

I tried with an RN52 module a few years back and gave up.

best
Thomas

[ahiddentableau]

Love the enclosure.  The rounded corners and the embellished cutout in the back are a classy touch and the overall rounded shape gives it a sweet sixities vibe.  You really did a fantastic job on that.  Great design and building.

Was there any particular inspiration for the way you shaped it, or is that just the way it happened to come out because of the mismatch between the small size of the project and the relatively large size of the materials having been made for big amps?

[thomasha]

I used different designs as inspiration, even amazon has a cheap small bluetooth speaker.
I wanted something as small as my phone, but with a nice wood finish. I saw some that were made of bamboo, but they looked cheap.

The piping that I used was the smallest that I could find. I bought some medium size, but it looks huge in comparison to this one. The same thing with the grill cloth. Because of the size only a small part of the pattern is visible.
At least I could use a shorter switch and a 3 mm led socket.