Home > Electronics, Lutherie > The Noisy Cricket Guitar Mini-amp

The Noisy Cricket Guitar Mini-amp

As I may have previously mentioned, I’m discovering the real joy of electronics and discovering how they work. The basic facts I learned as a young-in were important but without learning how and when to put the components to use, the knowledge was unrewarding. It’s my own fault for not digging deeply enough into the topic but that was then and in today’s world we have so much wonderful (and free) information placed before us it is easy to learn. This revival begins with the simple desire to understand more fully how the electric guitar functions. Understanding pick-ups, volume and tone controls, microphones and amplification. It sounds like a life-time of study or at least a full retirement of study for me.

Soldering Iron/Station

As I often do I wrestled with picking my “first project” for trying out my new soldering iron. After much rumination and anguish, I decided to lay down my $100 on the Hakko FX888D, soldering iron. Review after review after recommendation compared this Hakko to the Weller WES51. Clearly for a “serious” hobbiest, these were the two irons of choice.


Hakko FX888D


Although the Weller iron had its following, the Hakko was mentioned over and over again as a solid buy. The Weller had an analog display whereas the Hakko was digital. There were debates both ways as to which was better. In the end, I went with the Hakko which included a free wire nipper (cutter). Woo hoo!

What to Build First?

My interest in electric guitars and “tone” lead me to learn more about audio circuits. As I was surfing the web, I ran across a pretty awesome site with the odd name, “Runoff  Groove“. I discovered all the wonderful work that has been done creating guitar effects pedals which has been placed in the Creative Commons for anyone to enjoy. I learned that guitar effects pedals exist to allow unique sounds to be sent/played through tube amplifiers which on the whole wouldn’t have many effects built in to them. The amp that I have is Fender Mustang I, solid state modeling amp with beaucoup effects already built-in to the amp. In a practical sense, I don’t really need any pedals at this point in my playing what I needed more was to learn about the effects that I already had available to use.  I was intrigued however by the many mini-amplifier designs I had run across. Using one or possibly two transistors to power a speaker and/or headphones. I figured I could use the mini-amp when traveling so in that sense, it would be both an educational and somewhat practical “toy” and also not terribly difficult to build.

I considered building the “Ruby” amp until I ran across the “Noisy Cricket” from Beavis Audio Research.

Ruby - mini-amp

The Ruby – mini-amplifier from Runoff Groove

Noisy Cricket - mini-amp

Noisy Cricket – mini-amp from Beavis Audio Research

The circuits are somewhat similar and both are based on the LM386  low voltage audio power amplifier chip. The Noisy Cricket project page came with a lot more information about actually building the device, pictures, parts lists and just a bit more documentation to get my feet wet for the first time. When I ran across the “Radio Shack Protoboard Build Guide” link, I was sold! This would be my first project and “instant gratification”. Rather than muddle for days over what parts to buy and where to buy them, I’ll stop by Radio Shack, and get started soldering. And that is exactly what I did, only they didn’t have all the parts that I needed so I still had to muddle over parts and the best place to purchase them.

RS mini-amp build

Radio Shack mini-amp project sheet (circuit build)

It felt good to finally tin the tip of my new soldering iron and solder up my first circuit board since I built my Heathkit H-8 in the 1980’s. I had the skills then, but I was very rusty now. After a while I began to calm down and my hands quit shaking so much and the welds got better. Hey, its new equipment and everyone has to begin their journey somewhere and so I started mine…..

Noisy Cricket mini-amp RS build

Start of the Noisy Cricket build, Radio Shack version.

I came prepared with magnification (reading cheaters) but I was shocked at how I needed it for every component and every weld. Man, how am I ever going to coup with surface mount components? Perhaps I never will…. On future builds, I’ll opt to use sockets for the LM386 and power transistor which in this case is the venerable MPF102. This would allow easy repair and some experimentation but really, if I fry the LM386 I know how to desolder and replace it so is the socket really necessary? And as far as experimentation goes, that is what the breadboard is used for so by they time one is building I should think the design would have been mostly locked in. There are many ways to get a job done so I have some experimenting in my future.

Next up…

Well the promise of instant gratification was a might exaggerated when I discovered that RS (in fact two stores) didn’t have one of the potentiometers nor the transistor that was required for the build. I was excited to get started though and gave me motivation to find a parts supplier and commit to an order. So I did, in fact I have two fairly substantial orders in for supplies. I finally ordered from Futurelec mainly because they seemed to have all (or most) of the parts that I was looking for and at good prices. Their website was navigable but I haven’t been super impressed with their customer service yet. It doesn’t appear that I can called them and I have no idea how to track my orders so I guess I’ll email them to see if everything is alright. Meanwhile, there are a few things I could work on with the project case, e.g. drilling holes for the pots and LED’s. I really think it best at this point however, to just wait for all the parts to arrive before I do much more with it. I purchased enough components to build additional units but I’ll be first interested in how this one turns out before deciding on what will follow. I think my next project might be a DIY iRig, or maybe a complete practice amp with speaker cabinet or perhaps ……

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