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

[elt93]

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.

ABC powder extinguishers are quite widely available nowadays. The mono ammonium phosphate powder is also a type of DCP. I was just trying to point towards an extinguisher which would work well in a small home emergency scenario and cover most applications(kinda jack of all trades but master of none). Having separate extinguishers for each class of fire would be the best option but obviously isn't right for home application.
I'm sorry if the information I posted sounded wrong.

 

[elt93]

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.

You would have to point the jet at the wall of the tray which is opposite to you. This way the extinguishing medium will smoothly slide over the liquid on fire and starve it of oxygen and hence put it out. If u aim it at the base you'd spread all the inflammable liqui. Foam extinguishers work the best here.

 

[captrajesh]

ABC powder extinguishers are quite widely available nowadays. The mono ammonium phosphate powder is also a type of DCP.

I'm sorry if the information I posted sounded wrong.

Yeah you are right that even MAP is also a type of DCP but if you ask for DCP type extinguisher, no body will give you MAP based extinguisher. You will only be given Sodium bicarbonate based extinguisher which may not serve the purpose.

 

[captrajesh]

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.

In real life situations, you'll fight fires that wouldn't be confined to the boundaries of the tray so yes it's the base that you would aim at.

As for oil fires, even if one is an occasional cook, one would be well aware that hot oil and water is a lethal combination.

 

[captrajesh]

Duplicate post made due to connectivity issues is deleted.

 

[shafic]

hot oil and water is a lethal combination.

Perfectly right sir!!

 

[Fantastic]

Most important is to shut off the power. Anywhere ! At the equipment or the house fuse box.That way there is only enough energy from the components to burn and that shouldn't be too much. With the power on there will be endless energy for the fire to burn !
So for people who think their equipment might be capable of going up in flames ( like old amps ?) better to arrange a power distribution box that can be shut off quickly and safely ! Plus smoke alarm etc in case you are not around when the equipment catches fire.
This might be rare but one could always arrange things so that 'in case' of a fire it doesn't reach curtains and other fabric material nearby. As far as I know, amps etc. do not explode ! Capacitors can burst open and I've seen that happen. Never look 'down' into a gadget if you hear sizzling sounds. A capacitor could be bubbling away and the outer can could shoot up like a bullet ! They don't burn.
It's things like resistors and transformers that usually burn.That could lead to other inflammable parts to catch fire.

 

[Soundstage]

Sir,

Makes eminent sense. I keep a pencil with an eraser back handy. Started this a few years back when one of my amplifiers started mysteriously giving off a static electricity charge when fiddling with the knobs or switching off (it didn't have a remote). Sold off the amp and fortunately subsequent ones haven't displayed this tendency.

 

[Fantastic]

Sir,

.....started mysteriously giving off a static electricity charge when fiddling with the knobs or switching off ..........

Here again, the first thing to do is to ensure that your system ( the metal chassis ) is connected to your mains ground ( earth pin). For this to work your earth connection on your power socket and your mains wiring in your house has to have a 'real' connection to the ground of the building! That way you can't get a shock. This has been dealt with recently elsewhere on this forum.
The leakage could be due to several reasons and not all are dangerous. But if it's a leaking transformer it could be very dangerous ! You need to check it out.

But to repeat again. You must earth the chassis of the gadget that's causing the problem. If it doesn't go away, check the quality of your Earth line in your house before doing anything else.

Just realised that I should have said that 'everyone' SHOULD earth their hi-fi system even if they have no 'tingling sensation' while touching it's metal parts. That way any dangerous accidental internal short to chassis will be directed to ground and possibly blow the fuse but protect you from getting a bad 'or fatal' shock ! Doesn't happen often, but accidents are never planned !

 

[shafic]

Here again, the first thing to do is to ensure that your system ( the metal chassis ) is connected to your mains ground ( earth pin). For this to work your earth connection on your power socket and your mains wiring in your house has to have a 'real' connection to the ground of the building! That way you can't get a shock. This has been dealt with recently elsewhere on this forum.
The leakage could be due to several reasons and not all are dangerous. But if it's a leaking transformer it could be very dangerous ! You need to check it out.

But to repeat again. You must earth the chassis of the gadget that's causing the problem. If it doesn't go away, check the quality of your Earth line in your house before doing anything else.

Just realized that I should have said that 'everyone' SHOULD earth their hi-fi system even if they have no 'tingling sensation' while touching it's metal parts. That way any dangerous accidental internal short to chassis will be directed to ground and possibly blow the fuse but protect you from getting a bad 'or fatal' shock ! Doesn't happen often, but accidents are never planned !

Can't agree more!!

When i purchased my first TT 2 years ago, there was always a big 'HUM' from the speakers while playing. I had no idea about that issue as i was a amateur as regards vinyl ( still!!). Few times i called a local TT mechanic to solve this problem. He told me that it is "booming" not "humming":lol:. I thought the TT was a culprit. Then i got a second TT, same problem. So TT is not a problem. Then i purchased my second amplifier. Again same problem continued. Then i realized that something wrong with the power supply in my house.

I always felt a slight current shock when i touched the amplifier body ( metal) when amplifier was on and the electrical tester glowed.The amplifier used a TWO PIN PLUG. Also humming reduced ( not fully) when i touched the amp while the TT was playing. I was so fed-up and stopped to listen TT .

After some months i joined this wonderful forum and have started the vinyl experiments again. This time I consulted with my knowledgeable old friend ( Mr Vipin Tarun :signthankspin he told me that this issue may be due to bad earthing. The local electricians are clueless goats.

Finally i hired a QUALIFIED ELECTRICAL ENGINEER. He took out a separate earthing connection ( a long thick electrical wire) from the main board. He gave me multiple branches from the main earthing wire so that i can connect several amplifiers. That solved the problem. Now i am enjoying my TTs w/o HUM.

Lesson learned:-
1. The amplifier should have 3 pin plug.
2. Check the amplifier with the tester (on rusty part or screw) to ensure proper earthing.

regds,
shafic

 

[Naztone]

Hey guys
just a couple of things i wanted to add
1) While CO2 extinguishers are perfect for electrical fires in a enclosed space, they come with thier own hazards -
as the co2 releases from the extinguisher where it is stored at high pressure it expands with a drastic drop in temperature, if you are not at this point holding it at the correct insulated (wooden handles usually) position then u can loose a lot of skin/flesh to cold burns
CO2 is toxic to human health, alongside the depletion in O2 content due to a fire, if CO2 is used in a small enclosed enviroment the person using it may get asphyxia

 

[Naztone]

A few more points that will be of help
1) Primary means of extinguishing fires are:- Starvation (Cut off the fuel/energy supply), Smothering (cut off oxygen supply) , Cooling (take away the heat energy)

2) Like a few learned FMs pointed out, your first step should be to isolate the energy source - Switch off electricity, cooking gas supply............infact even if its a kitchen related fire please cut off the power supply to the kitchen - open electrical connections can lead to a spread in the fire thru short circuits etc

3) Please invest in a extinguisher & a fire blanket if you can find it
a fire blanket is basically a thick cloth made of non combustible materials, a wool blanket is fine ...unless it has a synthetic component ...in which case please dont

4) When using a DCP extinguisher - aim at the base of the fire - the chemical reacts in the heat forming co2 which cuts off the O2 supply to the fire
use almost continuous short bursts

5) If using a foam extinguisher, u want the foam to flow over the fire blanket it & extinguish the fire by smothering it - so never aim at the fire directly, but try to use a nearby surface so that foam slides on the fire

6) The best extinguisher for home use is the DCP extinguisher since it is the least hazardous and can effectively tackle electrical & carbonaceous fires......for an oil fire a foam extinguisher is your best bet......never use foam or water extinguishers on a electrical fire

7) The fire blanket is an excellent fire fighting tool for small fires - just open & spread/throw on the fire.......no need to worry are you using the correct extinguisher

8) the best way to fight a fire is to be prepared - most of injuries / major fires occur because the persons involved didnt know how to react.....what to do

by that i mean.....have a discussion with the family or your colleagues ......identify the potential sources of fire.......what fire fighting devices you have available...where are the circuit breakers....what actions you should take....let everyone add their suggestions......the idea is to talk things thru so that in that moment when you need to act decisively you are not caught off guard

eg: the cooking oil starts burning in the kitchen .....just cover the vessel with a steel lid.......no Oxygen supply...no fire :clapping:

 

[Naztone]

btw i started reading this thread thinking i would learn more about tube amps.....so i do realise that my posts are not fully related to the topic ....but i couldnt help adding my two bits

 

[Thad E Ginathom]

Audio equipment misbehaves in many ways, and most of them are not capable of causing death and destruction :lol:. It would be nice if this thread could have a more appropriate name, eg Fire Risk from HiFi and other Electrical Devices