On Electronics Safety

At Tropical Fish, we are pro-electronics safety. We don’t want anyone to get hurt working inside a tube amplifier. At the same time, we hate to see people writing online who overstate the dangers of working on a tube amplifier. It really seems like certain factions want to discourage people from opening their amps up at all. This is a bad thing.

As far as we can tell, there are a couple of reasons why people get overly dramatic about tube amp safety. First of all, a lot of people are probably just afraid of getting sued. What if someone’s installing your tube mod in the shower, but because their hands happen to be full of loofahs made from wet metal shavings, they decide to discharge a filter cap with their eyeballs instead and oh god they never even turned the amp off to begin with and the next thing you know you’re getting sued by their estate because you never specifically said it wasn’t okay to do any of that? That’s not fun.

But sometimes it seems like people don’t actually care about safety or lawsuits or anything of that nature. They just want to keep newbies out of the club. So occasionally you’re in a forum or a Facebook group and you’ll see sanctimonious statements like “if you don’t know the exact definition of [electronics jargon xyz], you have no business working on a tube amp because you’ll just electrocute yourself” or “tube amps have LETHAL VOLTAGES so take it to a QUALIFIED TECH and not just your BUDDY and certainly don’t service it YOURSELF that would be SUICIDE.”

This is concern trolling at its finest: pretending you care about a person’s safety, just so you can shame them for their choices. Specifically, the choice to be an analog electronics novice and not some grizzled old man that spent the 1950s holed up in his parents’ shed making ham radios and who now lives like a hermit in a tinderbox of old tube manuals and NOS carbon resistors. If you read enough forums, you’d think that tube amp expertise is something you’re born with, not something than can be learned - unless it’s from said “old-timer” who actually lives on your street and will absolutely be happy to show you around your amp in exchange for a couple of beers. Oh, wait - you don’t know anyone like that? What kind of poser are you?!

Not everyone spent their childhood taking apart the family VCR. Not everyone has access to a retired tech who fixed amps during the golden age of vacuum tubes. Not every currently active tech wants to be shadowed by an apprentice that pays in beer. But fortunately for us all, none of these things are required if your goal is to service your amp without shocking yourself. All you need is patience, time, and a trustworthy resource on electronics safety.

So, okay, warn people about lethal voltages. But if your next sentence is not a link to resources that will help a novice learn to mitigate the risk, you are part of the problem. You are the reason why analog parts are fast disappearing. You are the reason why there are so few good techs to replace those that are retiring. You are the reason why consumers are losing their rights to fix their own devices. Because you are telling people that it is not only too dangerous to fix their own amp, but it is too dangerous to even attempt to learn how. And if you think knowledge is dangerous, you are literally the villain here.

Below is a list of basic electronics safety information. It is not comprehensive, but it is a good starting point for most basic repairs.

Basic Electronics Safety Information

  1. Unplug the amplifier unless you are performing a test that requires it to be on. When plugged in, the power switch and fuse terminals are a shock hazard because they always have mains voltage across them.

  2. Always discharge the capacitors before working in an amplifier, even if the amplifier has been off for a period of time. *Find information on how to discharge capacitors here.*

  3. Stand on a nonconductive surface when working. Remove any rings or other jewelry. Work in a dry environment.

  4. If you’re about to use a multimeter to probe an amp that's turned on, make a plan regarding what data you’d like to collect before you begin. Clip the ground probe of the multimeter to the amp chassis, so that you are able to probe with one hand only. Keep your other hand in your back pocket so you aren’t tempted to touch anything.

  5. Make sure anything you’re using as an insulator is actually insulated. Just because it has foam handles doesn’t mean its insulated. If your tool’s insulation becomes damaged, throw it away, even if it was a really expensive tool. Never “chopstick” an amp with a pencil, because while wood is an insulator, graphite is actually conductive.

  6. This list of safety precautions covers some of the major hazards, but there are a lot of tips and best practices to keep your safe. Here’s two more safety guides with more info: [1] [2]

Some free resources for learning more about electronics:

Remember that vintage instruments pose hazards even outside of the risk of electric shock. Read our *Vintage Instrument Safety Guide* for more information.

Safety FAQ

Are you really saying that tube amps do not have LETHAL VOLTAGES and can’t actually kill a person? NO! Did you even read the article? Sure a tube amp can kill you. So can getting in a car and driving to purchase said tube amp. So can tripping and falling neck-first on a pair of needle-nose pliers. However, we all take precautions against those scenarios, for instance by wearing a seatbelt and not leaving pliers propped point-up in a mound of clutter. If you take your time, take appropriate precautions, research proper electronics safety, and your risk of injury when working on tube amps will be low.

Why is it dangerous to work on an amp that is turned off and unplugged? Capacitors can retain charge even when the amp is turned off. In an ideal world, a capacitor in a switched-off amp would actually stay charged forever. However, because capacitors are made from materials with real-world imperfections, they gradually lose their charge over time. But even if an amp has been off for days or weeks, that doesn’t mean that you can count on the capacitors being fully discharged. You should always safely discharge the capacitors before you work inside a chassis, and confirm that they are discharged if you step away from your project for any length of time.

Why do you want people to work on their own amps? Are you trying to put local techs out of business? We’re “local techs” and we want to see ourselves and our colleagues everywhere succeed. But, just a heads up, joining a forum to tell people “if you open the amp chassis you’ll probably DIE” is not a business model.one

Further Reading

Browse all of our articles on restoring vintage gear. Or, click on an image below.