Last time we took a look at the TROPICAL FISH capacitors in my "Systech Harmonic Energizer" and had a quick look at the other components. No intrinsic mojo was located in the caps. My homework was to go off and find real data sheets on the TROPICAL FISH caps and learn more about the shelf life of capacitors in general. I usually do not recommend New Old Stock (NOS) caps. There is a shelf life for most capacitor technologies. Most importantly, you don't know where that capacitor has been.
I was able to find a couple of things useful to understand the FISH caps. I did find an original data sheet for the Mullard TROPCIAL FISH caps. Thanks to the folks at Electro Jumble. Unfortunately, this document does not address storage and shelf life. The good folks at Vishay have a general film capacitor spec sheet that does address the shelf life. Check out excerpt below.
SHELF LIFE OR STORAGE CONDITIONS
Film capacitors should be stored under temperatures conditions from - 25 °C up to 35 °C, with relative humidity maximum of 75 % without condensation. The following shelf life is applicable: Parts supplied on tape or bulk: Minimum shelf life of two years without impairing the electrical parameters. Parts soldered on a PC board: Minimum shelf life of 10 years without deterioration of quality.
What this is telling us is that caps older than 10 years soldered on a printed circuit board may or may not have "drifted" from the original specs. NOS caps stored in a bag under almost ideal environmental conditions may or may not have "drifted" from the original specs. The 40 year old "Systech Harmonic Energizer" I am taking apart for this project may or may not have "drifted" from the original specs. How much? Really can't say but I wouldn't bet on these caps being in the best condition.
I can't count how many times I have heard folks say that they have to have original NOS fish caps because when they changed them the sound changed. Think about that for a minute. They removed old caps that had gone out of spec and replaced them with new in spec caps. The sound they didn't like (with new caps) was the sound that was the original intent of the designer.
Enough with the TROPICAL FISH cap mojo. This is a great article on how to decode not just the capacitor colors but a bunch of devices.
And, just to grind it in one last time There is no mojo in TROPICAL FISH CAPS This photo is of a different "Systech Harmonic Energizer" that does not have the Fish caps. If the caps were so important to the sound, don't you think Systech would have used ONLY Mullard fish caps?
Sorry for the rant, now that I blew the entire blog this week to fish caps, let's go on a tangent for a minute and figure out which Engergizer is older. The one on Discofreq's database or mine.
Most quality potentiometers have a manufacturer and date code. We lucked out because the Energizer has coded potentiometers. This website has a cool tool to look up pot codes and seems to produce relatively reasonable results.
My pot code is 3047419 and the one on Discofreqs is 1377618. My pots are made by Stackpole Electronics, Inc. in the 19th week of 1974. The one on Discofreqs website is made by CTS Corporation (Chicago Telephone Supply) in the 18th week of 1976. There is a good chance that my Energizer predates the Discofreqs Energizer by a couple of years. That means Systech replaced the fish caps with greenies. Cool. Again, NO mojo in the FISH CAPS.
I promise next time we will start the BOM and figure out where the orange wire on the PCB came from...