The Music Room - About proper safety and the potential hazards of electricity

Lethal High Voltage Disclaimer: Tube amps operate with lethal AC and DC voltages. All undertakings are to be at your own risk.

I assume no responsibility for any such damages incurred while building, repairing or testing electronic equipment of any kind whether tube, solid state or non-audio related.

Voltage and Current, are dangerous when careless...

Safety Rule #1:

NEVER use both hands near any energized equipment to measure voltages or currents. Also discharge power supply capacitors to avoid any possible nasty, biting DC discharge shocks.

The safe way is to firmly connect the Ground (black-negative) lead of your meter to DC (or Oscilloscope GND) to the Main Power Supply DC Ground.

Use use an alligator clip, solder a wire jumper to Ground or create a good adapter to make a secure firm connection to DC Ground.

Make sure that the Black (Neg) ground lead connection is also out of the way and does not tangle with your Red Probe Wire.

Use only one hand when measuring Voltage or Current, the other hand should be in your pocket or held away from the equipment.

This same safety principle applies to any electrical device such as a Breaker Panel.

Use only ONE HAND to unlatch any panel door.

The act of placing both hands on unknown metal surfaces can potentially create a current path through your Heart, and only a few milliamps can be fatal and stop your Heart from beating properly.

Some EE knowledge:

The reason why 120V - 0 -120V  (L1 - 0 - L2) residential and commercial "Bi Phase" exists, so the likelihood of a 240V Shock is minimalized. A person who dwells in a U.S. Facility, Home, Office, will only have a 120V shock if a mistake or accident should happen. The only way to accidentally receive a 240V shock is by actually "touching both HOT leads L1 and L2". This is why the 240V Mains is split into two 120V Phases, for safety. Hence the term split phase, or Bi-Phase. You would literally need to pull off the cover of your Breaker Panel and deliberately touch both L1 and L2 rails at the same time. The one Hand Rule applies here as well. A 240V Shock is far nastier than a 120V Shock, and believe me I know from when I was a Teenager replacing the Power Cord on our Electrical Range.

Electrical Theory and Music Technology

I have never been able to understand how a hobby like HiFi and Audio has become fraught with

all kinds of ideas and misconceptions. Electrical Theory is absolutely the basis for everything related to music

reproduction using active components like Amplifiers, Buffers or Preamplifiers.

Sometimes I visit other forums like Motorcycles, Cars or Hunting and cannot read the nonsense that I come across

on Audio Forums. People, if you want to learn, please pick up a Calculator, Pencil and a Book.

Nothing in the realm of Voltage, Current, Power and Energy comes easy, and an opinion has little effect on the laws of nature.

Learn resistor color codes, read about how Capacitors and Inductors work.

Spend time on a schematic and trace the signal flow with colored marker.

Learn Power Supply theory.

Learn what Regulation is.

Learn how a Transistor operates.

Learn how a Tube operates.

Learn how a Diode operates.

Realize that Troubleshooting problems takes years of practice, you cannot just wake up and fix stuff.

Buying an old Tube Amp on Ebay may not be your best means to have fun.

I rate all of the equipment I have worked on with a level of difficulty from 1 to 5, 1 being the simplest.

Please learn Ohms Law, Kirchhoff's and Thevenin's Theorems.

Learn what a Diode does, and look at Shockley's Equation.

Learn the safety aspects of changing out a Car Battery,  like which "pole" do you remove first?

Why do we have to clamp the Negative end of the jumper cable, to the dead battery Vehicle's chassis

and not directly to the Negative Pole?


This is how our ancestors learned not to walk up to a Tiger in the wild

How Children and Paper Clips are a hazardous combination for AC Duplex Outlets

Why does the US Electrical Grid use Bi-Phase Power in Homes and not just 240V like Europe?

What is more dangerous a 120V shock or a 240V shock?

Many of you would be surprised at the opinions people have when asked this question

and the reason why 120V is safer than 240V for residential AC power.



This hobby is hazardous when you start to tinker with Mains Voltages and High Voltage DC.

Numbers speak facts, not opinions or ideas, this is the bottom line people, reality is not based on conjecture.

There is nothing that you cannot learn, that can be as valuable as the knowledge of math, and it can suck.

Once you can visually manage basic mathematical relationships, a veil lifts as you apply these to your hobby

A = B*C, A = B2/C, and A=B2*C

Be given A and C to Calculate B?

Remember your High School Algebra Teacher?

Most teachers never explained why you were learning these symbols, that was a let down, I agree.

Practice formulas, until you memorize them, and can visually calculate when given simple whole numbers.

V=IR, P=VI, P=V2/R, P=I2R

When you can manage the very, very basic and fundamental relationships above

You map them to Schematics and the veil starts to lift.

The fog of Audio Forums burned off by the Sun of knowledge

You have then earned your knowledge, not a Google search

Something basic like a set of Christmas lights, is a simple Voltage Divider circuit.

Then learn to draw out a Voltage Divider, neat stuff.

Then you will understand why pulling out one Lamp makes the whole set turn off, a voltage divider.

Learn about Time Constants, Attenuation, Amplification factor, Low-Mid-High Frequency Analysis

Then when you pick up a schematic, the symbols start to make sense

And you will realize that it is a roadmap you are navigating

The closest thing to compare this to is a Piano or a Guitar Fretboard

A similar effort is needed to learn them well.

So what are the fundamentals...

Learn about Voltage

Learn about Current

Learn about Power

Learn basic Nodal Current analysis I1 = I2+I3

Learn about Voltage dividers Vt = V2 +V3 +V4

Learn how to calculate Series and Parallel combinations of Resistors, Inductors and Capacitors

Learn why very old Tube Equipment did not use a Power Transformer, and these Amps were called Widow-makers

There is a very cool place called knowledge where 90% of Forum Experts have never visited or cared to.

A Smartphone is not a College Degree, and don't ever believe the lies that that a Degree is useless.

Unless you study the lifecycle of an Antarctic bacteria with no chance of ever visiting Antarctica.

We have to be practical and wise, and this has nothing to do with academics, it comes from our Parents.

Once the Fog of opinions and endless forum conjecture (some insults) lift, you will realize how amazing an electron truly is.

You will automatically tend to visit less Audio forums, and seek true knowledge

That Chemistry Class now makes more sense

You will begin to shake your heads when you read posts, but instead, order a few good books.

It is all in our minds, and the care and feeding of this our most precious resource, our Brain

the fundamental way to also take good care of our ears and protect our hearing.

Then you will move on to Alternating Current analysis and signal tracing.




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