Upcycled Practice Amp Build Goes To Eleven

What do you call someone who gives the toddler in your life a musical instrument as a gift? In most cases, “mortal enemy” is the correct answer, but not everyone feels quite so curmudgeonly, and might even attempt to turn up the volume a bit. Such is the case with this wonderfully detailed practice amp for the grandkids’ electric ukelele.

The aptly named [packrat] [Professor Mayhem] really made this build a tour de force of scrap bin sourcing. The amp is built around a module salvaged from an old TV, a stereo Class-D amp that was modified to provide 30 watts output and a volume control. The driver came from a flood-damaged speaker unit, and the power supply from a gutted wall wart. The case was built with scrap plywood and covered with pebble-grain fabric to give it that pro audio look, while the chassis for the electronics was bent from a piece of sheet steel.

But it’s the tiny details that really sell this project. Everything from the pilot light to the pointer knob screams 1970s, as do the painstaking front panel lettering and vinyl “Monkeydyne” logo. [Professor Mayhem] even went the extra mile to create an etched-brass serial number plate, a mock specs and safety label, and even a QA inspection tag that was (sort of) stapled inside the cabinet.

We tip our hats to [Professor Mayhem] for this four-month labor of love and obvious nostalgia trip, which the kids are sure to love. [Professor Mayhem] does admit that some will argue with his decision to use a Class D amp and a switch-mode power supply, but let’s be real — for the application, it’s probably more than sufficient.

Thanks for the tip, [packrat].

19 thoughts on “Upcycled Practice Amp Build Goes To Eleven

  1. “What do you call someone who gives the toddler in your life a musical instrument as a gift? In most cases, ‘mortal enemy’ is the correct answer…”

    Eh, you gotta start them young. Yes, they’ll sound bad for a while (and if they’re learning a string instrument, a very *long* while), but once they’re over that initial hump, they’ll only get better. And if you build those neural pathways when they’re young, they’ll only really be able to look back on knowing how to play–they won’t remember the “awful music” phase that long.


    A Proud Band Geek

    1. One way to dispel those feelings of dread is to learn the instrument with your child. Your interpretation of the “noise” changes into indications of progress and your child is no longer learning alone.

    2. Eh, a guitar isn’t so bad, it’s not too hard to get a tune out of ad electric guitars can be practiced almost silently with headphones on too.

      Giving a small child something acoustic (so no volume control) and often difficult to learn (EG violin, saxophone, etc.) is an absolute killer.

    1. i got my kid a full mapex kit at 5. i listened to “we will rock you” out of the gate about 150 times. i just keep collecting instruments for her. she has an american indian flute, an indonesian flute, harmonica, travel guitar, tiny amp, stage mic, bongos, tambourines, castanets, ankle bells, the list goes on. and for her 5th birthday we took her to her favorite fish joint and they had karaoke, she proudly went up twice to sing. got the most applause of anyone that night.

      start em as soon as ya can and just suffer through, they learn super fast.

  2. Why would anyone have a problem with a Class-D amp and switch-mode power supply? Cheap, efficient … is it because it isn’t vintage-ish enough? I love the whole ‘reuse’ aspect.

  3. If I hated my kids I would give the grandkids bagpipes and drums.

    Now I love my kids and just want them to suffer mildly, so I’ll give them slide-flutes and tambourines

  4. One Christmas a few years back, with little in the way of available funds but still wanting to get my three young nieces a present, I ended up building them a variation on the Atari Punk Console noise toy. (The biggest modification was to add a push button as a gate, so it was only making noise when you held that down and not just being a constant drone.) They loved it. Their parents (my sister and her husband)? Not so much.

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