A Mighty Cacahuate caught in the wild

Student “D” sent me some pictures of his Mighty Cacahuate project with a twist and it’s too unique not to share. D developed a PCB for his build and mounted all the amplifier parts to a top plate as would usually be done. Instead of a boring wooden box, D dropped this into a boombox enclosure for all-in-one listening. I love to see the creative use of a basic schematic I posted here on my little website.

We initially troubleshooted some wiring over email, mostly due to my omission of the details of heater wiring and pin numbers on the original schematic. Once sorted though, D says the amp started playing and sounding great without a hitch.

It was an amazing feeling the first time they powered on.

-D

Careful there, D, that feeling is habit forming!

Update on the mono-blocks: left channel is done and right channel is coming together quickly. Write-up for the project is also underway. Looking forward to playing in stereo!

EL34 tester tubes, also considering springing for KT88s on this project
Night shot. Red glow through the vents is LEDs used as voltage references in CCSs inside.

Walking the line

When I got started with woodworking and amp building, cutting a straight line was the most intimidating part of just about any project. Not having the space or justification for a table saw, I tried more than one way of following a line with a jig saw and circular saw before I found something that works for me. Now I do not shy away from ripping boards to specific widths quickly and it only took some scrap and ingenuity.

What I found was a really simple circular saw jig made of a three or four inch wide 3/4″ board and some ten or twelve inch wide 1/8″ sheet. If you can find a board with a straight edge (preferably machined right from the lumber yard), you can cut a straight line. The jig is simply the 3/4″ board glued to the overly-wide thin sheet. You then zip your circular saw down the board with the shoe pressed against the straight edge to cut off the excess 1/8″ material. Viola. You now have a jig that will always cut just as straight as the board you used to build it.

saw jig

Here’s a picture of my jig (rebuilt this weekend because the old one was getting chewed up):

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My board is a bit wider because I also use this with my router for insetting panels.

To use the jig, I mark the piece that will be ripped or cross cut in two places and then connect the dots with the now arrow-straight edge of the 1/8″ jig base. Clamp it down and then let the circular saw ride against the thick portion of the jig. Because the saw’s shoe doesn’t change width, it will always faithfully cut along the edge of the 1/8″ material, provided you are making sure it is following snug against the thicker board. Straight cuts don’t get easier than this and I’d wager that this is at least as fast as setting up a table saw for every cut.

As far as measuring, I’ve always got a combination square near at hand (great for marking holes in top plates, too). This makes setting a repeatable distance from an edge quick and easy.

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If the thought of table saws and messy cuts prevents you from tackling your next amplifier or speaker project, hit the bargain bin at the lumber yard and whip up a simple jig.  This hobby doesn’t require expensive equipment if you get clever with the tools on hand.