This was a birthday present for my little sister. An old tube radio I found on ebay, at some point in its life all the tubes and radio circuitry had been removed as well as a lot of the hardware, however the old AlNiCo speaker was still in place (or an old one – not sure its original). The casing was in pretty bad shape, extra holes had been drilled in it at some point, still looked kinda nice though.
I made a new top panel from plywood, and wired in a stereo 3w amplifier board with a 3.5mm jack input as well as a second speaker out to make use of the other amplifier channel. Battery is held in a hessian pocked within the box, and I threaded some old rope through the holes where the old handle had been.
The picture of it hanging up is while I was ‘testing’ it by using it as my workshop speaker until I was able to give it to Ellie. . . The main picture shows it using my bizarre 12″ guitar speaker box experiment as an extension speaker, this added a little bass, but the thing is so sensitive it’ll needs to be plugged into a really loud cab for the effect to be noticeable. Unfortunately I didn’t really have the forethought to take some better photos before I gave it to my sister, hence no internal shots of the battery compartment.
It runs off 4 – 6AA batteries, possibly a 9v battery – but I didn’t manage to test that. The amp probably has too much gain for use with head phone outputs really, it starts to distort with my sisters iPod at about the half way mark- but then its pretty loud by that point anyway, it depends how bass heavy the track is, I might add some kind of high-pass filter if I get a chance to see if it improves things.
UPDATE
The old speaker managed to vibrate itself loose so its back at the workshop getting fixed, lasted over a year at least.
Doing some further research it seems the original wattage of this unit was 0.16w max! So 3w is really the end of the world for this speaker, hence the distortion, not from the amplifiers gain being too much, but because its 3 watt output is too high!
Hopefully I can find a way to improve the sound somewhat while I fix it, maybe simply undervolting the amp to limit it to half a watt might work. (Sept 2014)