This may not be the kind of project many would get excited about but if you’re a little more than the occasional builder this is great! It’s a very cheap and simple build. In fact whats’ taken me the longest time was deciding what I needed. I haven’t gotten around to labeling the knobs and switches, nor to printing a proper background for the meter, connecting and calibrating it – I just wanted to start using it ASAP and the meter was my last priority anyway. The box has 4 main functions:
1. Selectable dual polarity Mains voltage output (this is what I connect the circuits to). The center switch at the bottom of the top panel selects between -5V/+5V, -9V/+9V, -12V/+12V and -15V/+15V. The Mains output is on the right side of the box. These voltages pretty much cover most circuits I build, mostly being effects and synthesizer modules.
2. Three variable voltages, ranging between -5V to +5V. Most voltage controlled circuits use this range for control. 3 aren’t really enough but are a good start! The outputs are on the left side of the front panel.
3. The third section is taken straight out of Thomas Henry’s VCO Cookbook. It’s called a 10-Step voltage reference. An excellent tool for tuning a VCO. Two outputs are available on the front right panel: a fixed step voltage output (10V in exact one volt steps), and a tunable-bias output (with Coarse and Fine controls). This allows for a biased 10V span (-3V to +7V for example).
4. This may seem stupid but it’s actually what I use this box for the most: a hub! There are 5 more connections at the center of the front panel. Two are extra Ground connections, then there’s a connection to an external tone generator, to my multimeter and to my scope. For the most part I use one or two of them at the same time at the most. All these units are grounded to the box so I don’t need to move the ground wire between the various test units all the time.
More things to note: there’s a meter that can be switched between all the different variable and reference voltages. This does not give precision as much as a good idea on where things are at. It is currently not connected, not even glued in and will wait for the labels.
The box is connected to my PSU, which is set to -25V & +25V. The only thing I do with it is switch it on and off. 🙂