How dangerous are tube amps?

[thomquietwolf]

Looked up
Amplifier cap unloading for dummies
Didn't get much
Always thought ....
Builders would build it in...
Sheesh
They could....
Not a big bang
Just a slow drain....
C'mon they are geniuses(yes)...

 

[charlie chitlin]

They're only dangerous half the time.
Your heart does diastole and systole.
If you get 450 volts on one, you'll probably live.
On the other, you'll probably die.
It's very easy to learn how to discharge caps.
The trick is to never get it wrong.

 

[Stratafied]

I had no idea they were that dangerous.

 

[BluesForDan]

if you even lightly touch the wrong thing



heh heh heh, ain't I a stinkah!!

Unplug. Discharge. Measure. Then do. It'll become second nature. Most people who survive their first zap learn their lesson. There's a reason why they put those "no user serviceable parts inside."

 

[Wound_Up]

Poor OP getting crucified for his choice of words haha. Yeah mate the filter caps can kill you and of course our mains voltage is deadly too. But despite that, thousands of dumb amateurs like me have built amps. Before you start, um, tinkering ...do lots of reading and learn how to eliminate the danger. The TDPRI amp build forum is a great resource. You really have to be a little bit obsessive about safety and work slowly and methodically.

There's nothing inherently dangerous about building an amp. You're only soldering parts into place. The only thing dangerous at that point is the hot soldering iron lol. You don't plug it in while you build it so there shouldn't be anything to worry about until he's to the actual "testing" phase.

 

[Beerevermore]

I've changed out tubes in a couple of mine and plugged guitars in and out lots and haven't died yet, so there's that. Anytime else and it's going to a professional amp guy.

 

[rolandson]

Looked up
Amplifier cap unloading for dummies
Didn't get much
Always thought ....
Builders would build it in...
Sheesh
They could....
Not a big bang
Just a slow drain....
C'mon they are geniuses(yes)...

Yeah, but where's the fun in that?

Full disclosure, I took to using a lead with alligator clips on either end and a resistor in the middle, attached to a cap and ground, And Leaving It Like That, the day after I discovered I could fly across a room in a blue flash really well.

The flight was uncontrolled and the landing sucked.

And that was with one hand in my back pocket. Now it's gloves, one hand, discharge lead, insulated tools and tennis shoes on a dry floor.

Always.

 

[Dik Ellis]

VERY DANGEROUS!!!

 

[Wulfrik]

I’ve mentioned it before, but I once got a zap from a mic on a wet stage (which was in fact a curtain side trailer in a flash rainstorm). It burned my face and sat me on my backside in a split second, and I was a big, robust sort of fellow at the time but no match for that stuff!

After that, I’ve had a healthy fear of mains electricity… enough that I am extremely cautious about tinkering with my amps.

 

[charlie chitlin]

BTW, if your amp is tube rectified, the caps are drained in about 15 seconds after turning it off.
I wouldn't stake my life on it, but I've never shut down a tube rectified amp and then got a spark from a cap.
But I DO attempt to drain the caps.
Redundancy is good.

 

[jball85]

I want to tinker with tube amps but I am aware it can be fatal. How dangerous are they? Is it only the capacitors you need to avoid or can other parts be dangerous too?

Just be cautious, and do a little reading first. You could always start with pedals and work your way up.

You should definitely tinker with electronics, tube amps included. Tinkering is what gave us this brave new world we live in today. Or just shy away into a shadow of ignorance. I would go with the first option.

 

[thomquietwolf]

They're only dangerous half the time.
Your heart does diastole and systole.
If you get 450 volts on one, you'll probably live.
On the other, you'll probably die.
It's very easy to learn how to discharge caps.
The trick is to never get it wrong.

Like playing flute for a cobra in a basket?

 

[rolandson]

I’ve mentioned it before, but I once got a zap from a mic on a wet stage

Seems strange to say that fortune was smiling on you that day...! It could have been much worse.

You could have been knocked unconscious and awakened believing that you're really Barry Manilow or Tiny Tim...

Think about it!

(This is the precise reason for my doing a thorough shielding job and then cutting the ground lead to the trem claw, thus removing the bridge and strings from the circuit.

Some of the wiring in clubs left a bit to be desired)

 

[Nate D]

I had a tube amp stick me up and gun point and then pistol whipped me and stole my wallet.

I’d say tube amps are pretty dangerous.

 

[Bill Moore]

I suppose I grew up more curious than most of you. I was "tinkering" with all things mechanical/electrical when I was younger, and sure, I got a tingle once in a while.
In the Navy I got a little knowledge in their BE&E school, tubes were still used a lot on board ship! They didn't however, teach anyone to be afraid of circuits, or perform some sort of "ritual" while making repairs.
Common sense is all that's required!

 

[rolandson]

They didn't however, teach anyone to be afraid of circuits,

But "they" taught.
This "common sense" you spoke of, where did that come from?

Electricity isn't anything to be afraid of. It is however, something that requires respect.

Which has been the overall emphasis of this thread.

 

[Bill Moore]

Respect for capabilities is common sense, and common sense practices tell you not to stick your fingers into an energized circuit.
Tube amps are no more dangerous than any other appliance that plugs into the wall, and the bugaboo about the "HV" being deadly has no supporting evidence.
I fixed my nieces drier a while back, the fact that the heater side has 240V mains doesn't mean I'd do anything different while troubleshooting!
(I used both hands to hold my leads while determining the fault and am alive to tell about it!)

 

[Butcher of Strats]

Yeah one you die from electrocution by poking around inside an UNPLUGGED TUBE AMP, exactly how dangerous "they are" hardly matters.

Key fact, they retain lethal voltages long after being unplugged, possibly for many hours or even a day.

Discharging the caps can kill you too, so before attempting to work on ANY tube amp, watch a video about working on the exact tube amp in question.

For example one amp can have a line of obvious filter caps to discharge, BUT also have another filter cap mounted some other place where you do not realize there is a live 450v viper ready to strike.

 

[Butcher of Strats]

I’ve mentioned it before, but I once got a zap from a mic on a wet stage (which was in fact a curtain side trailer in a flash rainstorm). It burned my face and sat me on my backside in a split second, and I was a big, robust sort of fellow at the time but no match for that stuff!

After that, I’ve had a healthy fear of mains electricity… enough that I am extremely cautious about tinkering with my amps.

Remember also that mains voltage is around 120v while tube amps have a transformer to raise the voltage to 400v or even 500v.
Big difference, I have grabbed 120v dozens of times just not grabbed tight while standing in water or otherwise solidly grounded.

Added concerning fact is that if grabbing a live piece os metal that is still plugged in, it causes involuntary muscle spasm so you cannot let go.
IF, one finds themselves clutching a live wire they cannot let go of, it may be possible to walk or shuffle or fall away from it so it is yanked from your hands.

As for live mics?
Oh yeah in the old days of two prong house wiring etc etc it was very common to have 120v on a guitar or a mic.
But we would seldom be well grounded at the same time.
Got a good number of zaps to my lower lip from mics!

 

[Bill Moore]

It bothers me that when someone asks questions about working on an amp, all the parrots start squawking about "killer" voltages, but can cite no proof! please, you that believe that the low MA HV found in our amps can kill, post some proof! No one has been able to prove this myth to my knowledge, and I am curious how this rumor started.
rolandson, I've guess I've just been lucky in my 70+ years, but I've never seen any amp techs who work one handed either!