Decoding the Systech Harmonic Energizer pt2

Posted by Jim Black on 7/15/2017 to Bust Em Out

Last time we took a gut shot photo of the "Systech Harmonic Energizer" and had a quick look at the components. Nothing strange jumped out except we found some TROPICAL FISH capacitors. This time we have a closer look at the components. What exactly are TROPICAL FISH capacitors? Is there mojo in them fish caps?

Systech Harmonic EnergizerThe gut shot on the left gives a good overview but we need more detail about the components before we can create a bill of materials.

The first thing I like to do is to create an imaginary grid on the PCB. In this case, the potentiometers give a natural guide. The photo is high resolution so you can download it and get a better view. The industry standard is to label the components top to bottom and left to right. I did that for each grid. The first capacitor, C1, is the famous TROPICAL FISH capacitor.

Systech Harmonic EnergizerThese C280 capacitors were manufactured by Mullard Electronics, LTD. in the 1960s and 1970s. The color bands encode the value, working voltage and tolerance. The color bands are exactly the same as used for resistors. The caps are metalized polyethylene terephthalate. The Mullard caps were by no means the only company using color bands at that time. They just seem to be the most well known.

Systech Harmonic EnergizerThis chart shows how to interpret the colors. These colors are used through out the industry and are considered an industry standard. The color bands are exactly the same as used for resistors---with the exception of the working voltage and the tolerance. You don't see color encoded capacitors much in todays market. I don't like to use New Old Stock (NOS) for capacitors since they do have a limited shelf life. I'll look around and see if I can find a real data sheet and more engineering oriented information.

  • 1st band = Yellow or 4
  • 2nd = Violet or 7
  • 3rd = Orange x 0.001uF multiplier
  • 4th = White or 10% tolerance
  • 5th = Red or 250 wvDC
Putting it all together, our cap is 0.047uF, +/-10%, 250vDC. Not much mojo in this device. Just a decent coupling capacitor. I think if we stick with the metalized film caps of today we'll be fine. You can recognize these as the green caps that are so common (and cheap). The other TROPICAL FISH capacitor in the Energizer is rated at 0.1uF, +/-10%, 250vDC. If you are still not convinced there is no mojo in TROPICAL FISH caps, there is a gut shot of a Energizer on DiscoFreq's database that does not have the caps and appears to be a later version. Engineers always try to make the device better right? How did an english capacitor get in an American built effect? The caps were widely available and were the right price. Component substitution is common for electronics manufacturers. The substitution usually occurs when the engineering team approves a list of preferred and secondary manufacturers and suppliers. I once designed a video circuit that had a crystal oscillator with 5 approved manufacturers. All devices had the same tolerances and reliability specs. Again, no mojo...

Systech Harmonic EnergizerNow we are getting to the fun part. All of these effects have to have at least power, ground, guitar in and amp out signals. The +V power is the gray wire. The ground is the green wire. The guitar in signal is the yellow wire on the left and the amp out signal is on the right. How do I know that already? I traced the power from the battery and through the switch. That gave me power and ground. Then I traced the guitar in signal from the input jack. The signal remaining is the amp out.

But wait! There is something weird going on on this board. If you look at the gut shot photo there is a stub of an orange wire soldered into the board and our yellow guitar-in signal is soldered to the end of R2. It looks like somebody modded this Engergizer. We need to figure why. Maybe we can use potentiometer markings to compare our Energizer to the one on DiscoFreq's website to give us some clues.

Next time we explore these anomalies and build the complete Bill of Materials (BOM)...

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