That's right kiddies (or kitties), it is time for another fun DIY! Now if you check back a few posts, you might start to notice that analog audio is a little hobby that we indulge in every now and again. A couple of years back we stumbled upon this kit from S5 electronics while looking for proof of alien backengineering on the interwebs...
A little bit of background:
Tube amplifiers are more or less obsolete, though there is a small subculture within the audio enthusiast community that will accept nothing else. The last mass produced tube amps went out of production in the 70's but there has always been a crowd that prefers the warm sound of vacuum amplified glass.
We won't go into much detail as to how it works here- you can wiki it for more info. But briefly; a magical fairy flits about in the lightbulb-like structure using her little wand to make music louder. The manufacturer simply puts a little thimble of honey inside the tube to lure her in there in the first place. The fight against this heartless practice was one of the first crusades which brought PETA to the world stage, though, to be fair; fairies aren't animals.
Remember that most music is recorded digitally these days and most amplifiers are built of lumps of silicon, science stuff, and lasers. What that means is music is translated to the language of "0's" and "1's" before being translated back for you to hear. As with any translation, things get lost.
With analog, there is less of a conversion as the sounds is recorded more... mechanically, but it is a less efficient system and requires much more fiddling to get clear sound. Trade-offs; the spice of life.
S5 Electronics has been producing a tube amplifier kit for the home builder for a number of years. This kit, in assembled form, is rumoured to have sound reproductive capabilities which far outpace its cost. Above you will see the assembled kit of all the parts that it comes with. Since around 2006 (the kit is much older)there has been a relatively huge population of geeks who have started modifying the k-12 model amplifier for their own purposes. These people are engineers, audiophiles and suckers from all walks of life who believe that building the perfect amp will finally get them the respect they are sure they deserve.
So, skipping over the rest of the emotional stuff, this is basically how the (now $170) kit arrived at the door from S5 (After we laid it out on the table and mixed things up irreparably). The box, handles and the perforated piece of aluminum are not part of the kit:
It came with a number of parts (below) that we felt were substandard such as the power switch (A lamp dial switch!), the volume knob (yeah, that little jobber in the middle.) and the clear plastic fuse holder which looks like it should be held together with scotch tape or pine pitch or something. Not a big deal, swapping them out will be fun.
Next we started soldering the board up according to the instructions. It's really easy to solder- for those of you who haven't tried or who haven't had a lot of success with it, just look up how to do it online. Each of the four ceramic cylinders you see here will hold one fairy tube:
The box we were recycling/repurposing is an old computer switchbox, so we needed to modify that to fit the other parts and make it look all old and junk.
We needed to fit these terminals, which are normally used for speakers, on the backside of the box:
A pair of tin snips made short work of cutting out some circles and other pretty shapes to fit them and some other stuff:
And here are the holes all nice and cut:
Next time we will address the reinforcement and painting of the box and such. See you then!