Like many of you I found myself needing a the proper tools to set the ignition timing on my magneto bike but not wanting to drop the cash for a buzz box. After reading all the write ups on DIY buzz boxes I came a single conclusion. The parts to make those simply do not exist anymore. All the code oscillators listed were transistor based and have been out of production for a while. The ones that could be found were very expensive and of questionable age to be relied upon. So I found some modern components to make one. Now having said that I build, rebuild, and repair tube instrument amplifiers in my spare time so I had a lot of what I needed laying around. But I still think if you had to buy ALL the parts it would still be cheaper than an aircraft buzz box.

I found a modern IC based code oscillator on eBay, these can be ordered in customized configurations from the seller. They will add whatever connection points you would like from the menu and assemble the board for you for around $17 the rest was just leads, a speaker, battery leads, battery, a knob, and an enclosure. I will actually list the specific parts I used this weekend.

Mine has a 1/4” mono phone Jack for the leads but you can order it with screw terminals if you like, I used a set of battery leads from an old broken timing light and a radio shack 1/4” mono phone plug with screw terminals. The speaker was a 3.5” 8♎️ Speaker out of an old CB base station.

I added a SPST toggle switch in series with the + batt lead for power I had laying around. It was a 12v rated automotive switch but any old 120vac SPST switch will work just fine. I have a project enclosure coming and will post more pics of the finished project once assembled along with a video of functionality.

Full list of needed components ( this could vary depending on the board configuration you order )

1. Code oscillator board $17
2. 9V battery $3.00
3. 9V battery leads $1.00
4. Test leads (alligator clips and wires) $2-3
5. Speaker 8ohm 5W ish $4.00
6. Enclosure 4X6" $11.00
7. Knob for 1/4' (6mm) potentiometer shaft $1.00
8. 1/4" mono phone plug for test leads ( if 1/4 jack chosen) $3.00
9. SPST toggle switch $2.00

This puts the total around $45 if you have to buy ALL the components. This is a savings of around $30 (more money for enduro parts!) if you were to buy a ready made buzz-box on the low end.

Ok got it wrapped up, had some extra speaker cloth laying around from a Silver face fender Bassman rebuild I did a few years ago.