What should you do when an Amplifier (Tube Amp) suddenly misbehaves?

[shafic]

Dear FMs,

Two years back one of my amplifiers suddenly sparked and caught fire. My home's main tripped. I tried to slap with some newspaper to put off the small fire n smoke.Luckily the fire subsided and no one was harmed and no damage was done to the speakers. The cause was the bursting of the capacitor in power supply section of the amplifier.

After that incident my heart always starts to beat fast when i operate a vintage amplifier, particularly tube amplifier. It has become a (tube?) phobia for me:lol:

Now days many FMs are using tube amplifier stuff and kids are around.

Asking Knowledgeable FMs that,

What precautions should be taken if something goes wrong?

How to deal/behave in such situations?

Pls share your views.

regds,
shafic

 

[reignofchaos]

Re: What should you do when an Amplifier (Tube Amp) suddenly misbehaves?

Make sure any bulged or failing caps are identified and replaced. That would me my only advice.

 

[mekr]

the same thing happened with my brand new amplifier,when initially i installed it out of the box,when i reported the problem to manufacturer ,i was immediately sent a replacement capacitor and my tube amplifier worked fine after the replacement.

enjoy your equipment

mekr

 

[Fantastic]

I would recommend that you use a mains extension box with a resettable trip in line with the supply. You get them for various current ratings . It's a small cylindrical device with mounting screw threads and a red button. If it trips you need to depress the button again. Basically if anything overloads it will shut off power without taking out your house fuse. You can use a 4Amp unit which probably is enough for your amp. Available with electronic parts dealers....Lamington road in Mumbai ! I can't remember the brand name. I have one around somewhere. Not fixed it yet ! Maybe it's called a mini circuit breaker. Try Googling it ! It's made in India.
I'll search for mine. I'm out of town for two days from tomorrow.

 

[shafic]

I would like to know, what one should do in case this actually happens.
Can one use a fire extinguisher? Is it safe?

 

[Thad E Ginathom]

It would have to be an extinguisher made for electrical fires. No Water !. It would be filled with some sort of powder or non-conducting foam.

Probably there is more danger in the kitchen --- but your experience shows that it can extend to the listening room too.

 

[captrajesh]

I would like to know, what one should do in case this actually happens.
Can one use a fire extinguisher? Is it safe?

First thing to do would be to pull the plug if u can access it. If u can't, shut the main. Most households do not have access to fire extinguisher. Use any extinguisher that have markings B & C. Do not use ones having A on it; they are water based. Some have markings A B C. They can be used too.

It would have to be an extinguisher made for electrical fires. No Water !. It would be filled with some sort of powder or non-conducting foam.

Foam extinguishers are usually water based and are used to douse petroleum fires. It must not be used on electrical fires.

Fire extinguishers marked A are water based; those marked B & C are either powder based (sodium bicarbonate) or gas based (Carbon dioxide) Those marked A B & C are based on Mono Ammonium Phosphate powder.

Earlier we had really small and handy extinguishers based on Halon gas but they are now banned under Kyoto protocol as the gas is a floro-chloro carbon category and affects the ozone layer. However, they are still permitted to be installed at critical locations.

 

[Thad E Ginathom]

Super information.

Are extinguishers specifically suitable for electrical fires marked as such, in plain English, at all? Or do we have to know those letters?

As an aside, I've often wondered about water-based extinguishers in the home, office, etc. fires often have an electrical cause, and even if they don't, there are going to be appliances, sockets, etc around. Electricity is never far away.

 

[Soundstage]

Keeping a dry powder fire extinguisher handy is an excellent idea.

However, make sure it is kept out of the line of sight of the significant other, lest she be tempted to connect it to your head in a violent fashion on seeing yet another new component in the system:lol:

 

[Simon Wires]

Shafic,

Before you could finalize on the right fire extinguisher kit, as a quick measure, keep nearby a thick woolen blanket.

 

[Vinod.R]

One more thing for our wives to hit our heads with! (A fire extinguisher!)

Cant a trip fuse kind of box (I am no expert in electrical fuse boxes) be fitted near the tube amp line itself? And always have a handy wooden stick or non conducting stick to switch off as we ourselves can get a electric shock by touching a switch with our fingers.

 

[captrajesh]

Are extinguishers specifically suitable for electrical fires marked as such, in plain English, at all? Or do we have to know those letters?

Here is a pictoral depiction for easy comprehension:

Source: What you Ought to Know about Fire Extinguishers | United Hoisting & Scaffolding Corp

Add to that, a new category called 'K' for Kitchen for type of fires in Kitchens involving fats and oils.

As an aside, I've often wondered about water-based extinguishers in the home, office, etc. fires often have an electrical cause, and even if they don't, there are going to be appliances, sockets, etc around. Electricity is never far away.

Yes that is a concern. That's why, the first thing one should do in case of fire in an electrical equipment is to cut off the mains. This holds good even for cars. Quite often, we hear horror stories of cars catching fire bang in the middle of the road. That's why, the positive terminal of my car battery wiring is not tightened fully. It is tight enough to hold on but loose enough to be pulled off if required.

Of late, 'Water Mist' type fire extinguishers have been launched which are said to be safe even on electrical fires but am yet to see one.

 

[captrajesh]

This site has some good information on fire: Types of Fires and Extinguishing Agents The Fire Equipment Manufacturers Association

 

[shafic]

Shafic,

Before you could finalize on the right fire extinguisher kit, as a quick measure, keep nearby a thick woolen blanket.

nice idea simon.:clapping:

One more thing for our wives to hit our heads with! (A fire extinguisher!)

vinod

Keeping a dry powder fire extinguisher handy is an excellent idea.

soundstage

I always keep a wooden stick nearby to be used to put off the switch.

 

[shafic]

Thanks Capt!!

Thank you for sharing your considerable knowledge!!

regds,
shafic

 

[elt93]

The dry carbon powder(DCP) extinguisher will douse all classes of fires. However if your amp dies catch fire and you decide to use it, the amp will be beyond repairs for sure. Carbon dioxide extinguishers work best for class C(electrical) fires but isn't really a good all rounder for home use as it needs routine pressure inspection and is next to useless for the next most common household fires, which is class A (paper, cloth, wood, etc). A DCP extinguisher will cover both as well as class B(oil) fires. From my experience for home usage it's the most practical solution.

 

[captrajesh]

Dry Chemical Powder (DCP) fire extinguishers would be ineffective against Class A fires. See the rating on the fire extinguishers. I've also experienced it to see why and how Paper, clohes, wood etc have a tendency to smoulder and would reignite within no time. Only ABC type fire extinguishers which contain Mono Ammonium Phosphate Powder which physically resembles Dry Chemical Powder are some what effective against A class fires. It is not correct to spread misinformation.

Powder is not a clean agent (leaves powdery residue) which is nothing but sodium bicarbonate which is corrosive. Hence some parts of the amp might be rendered unusable. Carbon di oxide is a clean agent but not as effective as Dry Chemical Powder.

 

[captrajesh]

@Shafic knowledge is for sharing. What's the point otherwise!

 

[captrajesh]

Are extinguishers specifically suitable for electrical fires marked as such, in plain English, at all? Or do we have to know those letters?

Here is a pictoral depiction for easy comprehension:

Source: What you Ought to Know about Fire Extinguishers | United Hoisting & Scaffolding Corp

Add to that, a new category called 'K' for Kitchen for type of fires in Kitchens involving fats and oils.

Just realised that I didn't address the query fully.

Unfortunately plain English is not understood by one and all. Writing in multiple languages would be of no use because these equipments are used in an emergency situation wherein there would neither be sufficient time nor would people be in a state of mind to go through the text. Hence, symbols denoting the type of extinguisher is depicted for easy comprehension.

But unfortunately, awareness of even such basic information is abyssmal amongst general public. IMO, the right way would be to teach at least the meaning of these symbols to children of Primary classes but sadly that doesn't happen in India.

 

[Thad E Ginathom]

In my last office job in London we used to regular fire alarm tests and fire drills. Sometimes this included taking us out to a back street, pouring some inflammable liquid into a tray, lighting it, and showing us how to use a fire extinguisher. I've forgotten it mostly, but IIRC, the thing is to point the jet at the base of the fire?

Slightly offtopic, but I feel that any fire-danger thread should include a warning against throwing water on kitchen oil fires.