Copyright 2000-20015 R.G. Keen. All rights reserved. No permission for local copies or reposting from sites other than http://www.geofex.com.
This project involves wiring and working with AC mains line voltage. You MUST pay strict attention to safety warnings and MUST be able to do the wiring safely. This article will not teach you to do that - you have to come prepared to do that on your own. If you don't already know how to do it safely, do not try this project.
April 10, 2015. This project has been up on geofex for fifteen years. I believe it was the origin for commercial many-output power supplies for pedalboards, and for the many dying battery simulators that are common in the DIY effects world. However, it does involve some risks. That warning is serious. In a couple of forums on the net I have seen some questions that have finally made me conclude that there are people coming into the DIY effects world that will ignore the warnings however they are worded. So, regretfully, I am removing the technical content from this article.
|Ever get just totally screaming frustrated with *both*
replacing batteries in effects on your pedalboard *and* with the hum
from an AC-adapter power supply? Do something about it with the Spyder.
Why do pedalboards hum?
It's possible that you have a bum power supply. If your power supply is a salvaged wall wart that puts out DC, it may or may not have an internal filter. It may or may not have an internal regulator to make the power smooth. Both of these will make for bad, possibly insufferable hum...
| So how do we bust the hum?
This isn't rocket science, by any means...
An alert reader has already asked if the regulators in the Spyder could be made to simulate the response of an almost-exhausted battery. Yes, it can, the same way the pedalboard power supply at other places on GEO can be made to.
To do this successfully, you have to use an adjustable regulator. The LM317L does this very
|well. The 317L sets you set its output voltage by means of resistors. I've shown two fixed and one adjustable resistor here; with the values shown, it will put out 7.0 to 9.5V. The variable resistor in series with the regulator output simulates the increased internal resistance of an almost flat battery. It can be tweaked from 0 (fresh battery) to 200 ohms (dying battery).|
Instructions for a Do-It-Yourself Multi-Winding Spyder Transformer
If you're a stubborn do-it-yourselfer, you can make your own transformer for the Spyder instead of buying either eight small ones or the nine-winding job. This involves working with AC line voltage. You MUST pay strict attention to safety warnings and MUST be able to do the wiring safely. This article will not teach you to do that - you have to come prepared to do that on your own. If you don't already know how to do it safely, don't try this project. It is far safer and in many cases cheaper to buy the transformer offered by Ted Weber. Only consider winding your own if there are circumstances which make this your only good option, and even then be very certain you can do this safely before trying it at all.