Wednesday, June 24, 2009

Under the stairs

I’m really behind on the updates, sorry. I’ve been doing some real-world stuff that didn’t leave much time for much DIY guitar-related fun. I am happy to report that one of the reasons I haven’t had as much time to tinker is that I’ve actually been playing the guitar a bit.

One of the things that took up some of my time was sorting out a new property back home, which required a rather long return flight, not helped by the fact that the airline forgot to load the headphones for the entertainment system on the way there, and I hadn’t brought my own for the first time ever.

While I was back home, I rifled through some stuff that I had left at a friend’s house and stumbled across a stomp box I made just after finishing the DIY Strat. I had totally forgotten about it, and even if I had remembered I would have been sure it had been thrown out.

Anyway, for the very few that may be interested, here it is. Note the professional enclosure (not)! What a great colour (grey primer covered by lacquer, which was all I had at the time).

The circuit is one of Aron Nelson’s designs (if you don’t know who Aron Nelson is, but are interested in DIY stomp boxes, then Google his name now). This particular circuit is “The Hornet” and the circuit diagram can be found here: (scroll down a bit to find it)

Unfortunately when I made this, I didn’t really understand how to do the switching, so I ended up wiring it up like this:

I mean, it works (sort of), but it’s not a good way to wire it up for a couple of reasons.
Firstly, this is why it works...

The switch has 4 legs. In one position, legs 1 and 2 are shorted. In the other position legs 3 and 4 are shorted.

When poles 1 and 2 are shorted, power is sent to the circuit.

When poles 3 and 4 are shorted, power is disconnected from the circuit, but the input is shorted to the output, creating a bypass.

However, here’s why it’s not a good way to wire it up...

1. Even when no power is applied, and a bypass is in operation, the circuit still manages to affect the sound, for example by creating some sort of a path from the signal to earth.

2. When the switch is pressed, the circuit is activated at the same time as power is applied, and a loud popping noise is heard.

For those that are interested, in the next blog post, I’ll show you the correct way to wire up a switch in a stomp box:

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