Threat of fire from audio equipment

Just read Art Dudley's new piece in Stereophile, and found myself becoming all sorts of worried. For many, many years now, I've left solid state equipment powered on -- except during thunderstorms or when heading away from home for extended periods. Now, I'm rethinking this practice.

See Mr. Dudley's article here:

My questions:

Is what happened to him the rarest of things, like someone's being struck by lightning? Is putting an amp (or another piece) into standby mode any better than leaving it on -- when it comes to preventing fire, that is -- or can a unit in standby mode burst into flames just like one that's powered on fully? Do others worry about fire? As much as I appreciate a fully warmed-up system, if fire is a legitimate concern, I'll routinely switch things off when I'm not around and listening. Or about to listen.

I'd love to learn what others -- especially those who understand engineering and electricity -- do with their equipment.

Thanks very much.

It happens...I"m all tube so I definitely turn things off when I'm not listening...

I want to know what amp they were using , .  Sounds like cheap build of materials.
Funny thing, In a few separate posts there was talk of the cheaper variety of tube amps from China. The tube amps, so affordable for a few hundred bucks or so, audio guys were buying them up. I had mentioned the various articles I read about Chinese factories and swapping out counterfeit parts as a danger for fire or electrical mishaps. Not too many people buying these amps seem worried....
I used to leave my tube preamp on all the time until one of the caps in the power supply went bad and caught on fire.  The fire was contained in the unit, but the smell hung around for a while (it was the reason we went down to see what was happening, so that was a good thing).  So I don't leave my electronics on 24/7 anymore.

If you read the article, you'll see why Dudley (properly in my view) didn't  name the maker of the amp.  Even the best of components in an amplifier can go bad.  Now if it was a design flaw, that might be a different matter.
Had that happen once, but it was the power company’s AC coming in to the house.

Left the stereo on, was outside, playing with and walking the dog....came back in and the power was cycling, on and about the rate of just over 1 on/off cycles a second.

Right about at the correct rate to blow up a power amplifier, as best as possible.

In this case, the amplifier was of the kind with no protection circuitry of any kind, other than a fuse and power switch. The best sounding kind of added protections, which is: NONE. (’Best’ in audio quality means: Go big or stay home)

It also had three hundred thousand microfarads of capacitance in the power supply, at +/- 90VDC, or 0.3F (farad)/90VDC. This amp would run for 30 seconds after it was shut down. Full DC capacity, zero problems with being like a DC power supply, instead of being an amplifier for audio. (hitting the power switch will not save your speakers, foolish puny man!)

The amp had blown a main capacitor, but just...kept on going, zero in the way of failsafes (just the way I like it), but also blew a set of prototype speakers, where the drivers where no longer available, anywhere.

Not my best day, but far from the worst. It was just audio, not life nor..the records.

The AC continued to cycle like that for nearly an hour.

I still like my amplifiers to be that way. The gain in sound quality from the lack of the extra circuitry, relays, etc, is worth that much to me. I’d pay many thousands for it, like others do in various ways. In this case, I paid in damaged goods, in the given luck of the draw.

Art was burned by chance, and not much else. 

We don’t truly know that, the capacitor might have been run too close to it’s voltage spec, but in well designed gear, it’s unlikely to be a problem even there. (re fire)

Conservative design rules the roost in the west, as, in the west...we’ve learned all the fire lessons we ever want to see or deal with, over the past 100+ years of electricity in homes. We've built up a system of specifications in parts and design and use of parts.. so that the correct amount of overhead remains in any given part and design application. All our build and design professionals are trained in this way. (that would be a 'design technician/technologist'. We used to have these as actual degrees available in schooling... engineers don't get much on this all important point in electronics education/build)

China? eBay? Not so much. Very very not so much.

All that DIY stuff out of china is not done by the level of professionalism and knowledge that is required to make sure that things are safe, stable, and long lived and don’t start fires in your home. The parts inside don’t have enough quality and overhead built in, the kind that comes from quality base materials inside the given part itself, nor the designer and builder of the part having the background for it in lore learned.

20 years from now, it will be better, but right now, it is still the wild west in circuitry and parts, out there in eBay DIY cheapo land.

Few in the west, as casual buyers, have any chance to understand such, as they’ve been under the protective umbrella of professionalism in electronics --- for their entire lives. So they buy this eBay kinda stuff, with no idea whatsoever of what they’ve allowed into their homes. A literal Sht-ton of dangerous and bad design, build and part decisions, in quite a few of them. And if that stuff burns your house down, and the insurance company figures it out, you’re out of luck. That stuff generally has zero regulatory or inspection approvals of any kind.
Thanks for calling the article to our attention, Howard. Regarding your questions, IMO all that can be said is the not particularly helpful common sense notion that in general the risk is very small (perhaps less than the risk of driving a car), but it is not zero. And I would expect that leaving a component in standby mode reduces the risk greatly, compared to operating mode, but again not to zero.

Personally the only component I’ve ever owned that I left on 24/7 was a vintage Mark Levinson ML-1 preamplifier, from the late 1970s, which had no power switch, was designed to be used that way, and had a fully enclosed metal case without even any ventilation slots. And was not located near anything particularly flammable. Between me and the prior owner it ran essentially 24/7/365 for more than 30 years, before developing some functional (as opposed to safety-related) problems.

FWIW, with that exception my own policy has been to play it safe, and just allow time for my components to reach a stable operating temperature before doing any critical listening. That means no more than an hour with any component I have owned, and less than that in most cases.

Best regards,
-- Al
Well the question of whether to leave Amps on 24/7 has finally been answered.  
Over the many years I had my stores, I never had anything like this happen.  We left most equipment on 24/7 in all the stores and I still leave solid state gear on at home.

I did have a few pieces blow-up/catch on fire, but they were operator error situations, not the unit's fault.

Toasted quite a few drivers in my time also...
Wellll. lightning can do crazy things, with the unit on or off.
But a) it should be fused so that the fiuse protects you. I under-fused all my products - they would not pas full power on a test bench the way we shipped them. But in real life, you can barely get 10% out on a steady state basis - the peak to average ratio in audio is like 20:1
Sadly i still get calls "my amp wont turn on". me: did oyu check the fuse?"Why did it blow a fuse?" me: to save its ass and maybe yoursok, i didn't quite say that.

Next, never put a product that is open with vent holes on a flammable surface. Put it on a piece of metal, a block of wood..... (its not that flammable) - but NOT carpet.
If the unit has standby - do it. Mine did - only the low power circuits were on 24 x 7. The rest warmed up in 30-60 minutes depending on how fussy one is.

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I had it happen to an Adcom amp upon turning, or should I say "firing it up". A flame appeared coming up from the top vented cover. I turned it off. No fire ensued. Adcom fixed it. No further issues after that. It was NOT in a equipment rack AND I had it on a concrete slab. Joe
I had a Nu Vista preamp years ago which incinerated itself due to the dumb design. Double decker electronics in a small case with no heat sinks or visible outlets was an accident waiting to happen. Fortunately the guy who did all my repairs and mods salvaged some parts and built a passive pre in the Nu Vista case which sounded better than the original pre and I still have it.
Thanks for your responses, all -- Al, especially. As of now, I'll be keeping everything turned off until shortly before it's time to listen. Peace of mind is worth a lot.

Now that I will call a reliable piece - Levinson preamp.
I have transistor equipment and cannot hear any difference after two hours of warm up, and the difference between one hour and two hours is small. This doesn't mean that others wouldn't hear or/and that I wouldn't hear it with other equipment. I don't leave the equipment on unattended, this includes overnight.
seen many cheap chinese power amp/mixers pcbs catch fire, mostly small components.I leave all my equipment switched on, especially avr's which have the fate of not coming on again.Cant afford to loose my hk5000, the 4000 went that way.
the rotel 980 cda and dap are only switched on when used.heaven forbid one of them die on me, they are the best i have ever owned.cant take a chance with transformer items as our supply can hit 320vavc when a substation burns up, common in our new sa!bright lights...once so far in my area.
The title of this thread should read "BE AFRAID, BE VERY AFRAID".  The chances of your equipment, excluding tube power amplifiers, catching fire is virtually nil.  Your laptop computer or cell phone are far more likely to self-incinerate than your stereo equipment.  A few sparks, a little smoke and a foul smell -- that's possible, but again highly unlikely.  And those events won't set your house on fire unless you've placed your equipment upon a bed dried evergreen needles.  If you really are going to worry about transformers exploding or lightning strikes, then you should also worry about making your system earthquake and tsunami proof.
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If your equipment caught fire or your house burned down raise your hands.
I can only assume that neither onhwy614 nor rodman99999 read the Stereophile piece that prompted me to start this thread and ask the questions I did. (link included above.) 

An excerpt: "I didn't get much sleep that night, owing to the lingering stink—which had reached almost every corner of our home—and to my lingering worries about potential carcinogens. In the morning I set about cleaning the house, which proved a lengthy task: three days of scrubbing walls, ceilings, hardwood floors, and hardwood furniture, often multiple times—even after four washings, the wall behind the amp continued to reek—plus laundering bedsheets, pillowcases, slipcovers, and clothes that had been neither shut away in a closed drawer nor hung in a closed closet."

onhwy614 writes of an exploding transformer; the part in question appeared to be an electrolytic capacitor. He writes of a foul smell; what happened in Art Dudley's home was quite obviously  nothing so forgettable.

I'm as far from an engineer as one can get. I'm just a music lover who also appreciates good sound. I was very surprised by what I'd read in the Stereophile piece, and wondered if others, folks with more knowledge than I, might weigh in with some considered replies. I'm thankful to those who did.

-- Howard

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@elizabeth : +1(x2) A smoking/stinking electrolytic is a LONG WAY, from a burned down home.       
I remember the time I informed a fellow soldier that the Lithium batteries we were using needed to be popped before they are disgarded and moved away from other batteries. And they were not to be placed into big piles. Breaking a seal , popping them, allowed the last fumes to be released away from everything outside. Of course many soldiers did not care to understand and the batteries were piled up. After a brief field training excercise, we arrived back to find one whole bay of our motor pool caught fire because of lithium gas buildup. So yeah I am safety conscience...
Fires happen, fumes can cause many problems and I would never want to lose any family members of home damage because of potential problems. I think this thread can make people think about possibilities, however remote they may be.
Let’s not forget smokers who smoke while taking oxygen, just saw one yesterday at the hospital where I work....
third degree burns to his face and neck. He probably never thought it would ever happen to him....
Some "smart" phones have a history of burning people, homes and cars. How many carry theirs around in fire-proof enclosures, or turned off?
Hodu, I read the Dudley article and thought it was unfortunate.  But then again, I don't think Dudley's experience reflects a typical audiophile.  He's into esoteric and/or vintage tube amplifiers which truth be told, I wouldn't leave unattended either.  Also, he swaps out dozens of pieces of equipment a year.  If a fire is going to happen, it would happen to someone fitting his specific profile.  For a typical solid state amp/preamp/dac or even a small tube preamp owner, fire and explosions are not something to give much thought to.
Someone mentioned a power substation burning and the resulting possibility of damaged equipment.  I'm just not going to lose sleep.  An unnamed rogue nation in western Asia sending malware or a virus to corrupt your computer/music server/phone is far more probable.
Reminds me of a 1KW isolation transformer in the TV repair workshop where I worked which went bad. It was mounted on the wooden partition and the really loud vibration and plume of smoke were astonishing.
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I thought some amps have fans, that would that add enough oxygen to a spark or flame... after all some fans are supposed to kick on if the amp gets too hot.
I always keep a fire extinguisher nearby. I recommend everyone keep a fire extinguisher near their audio system. 
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I'm raising my hand.

I never leave equipment on 24/7.  In my opinion, that is asking for something bad to happen.  The only equipment that is left on is a refrigerator and you really don't have a choice for that one.

I watched a tube blow in my Audio Research REF 250 Amp and it took out resistors (yes more than one), capacitors and traces.  it was spectacular and definitely was on fire.

I have a Krell KBX balanced electronic crossover for my speakers and it has a separate power supply and the entire unit is left on all the time because it doesn't have a power on/off switch.  Well, one day I smelled smoke and lo and behold the unit failed dramatically with out being used.  That is why I unplug it when I'm done listening. 

I turn off everything in my system. It is fine for people where this has never happened to offer their opinions, but really it make no sense to leave this stuff on all the time and I was fortunate.  I was home when the two incidents happened.  So, I turn everything on an hour or so before serious listening.  Hear no difference a more than an hour.  I have tried.

I turn everything off after listening.  I unplug everything when I leave for extended periods of time, say more than two days.

people that don't really understand electronics or power can talk all they want but, electricity will take the easiest path to ground and you, your kids, your wife/husband, pet, home may be the easiest path. 

I've been in the electronics and power industry for well over forty years and I can't tell you how many times a muti thousand dollar circuit or piece of equipment protected the five cents fuse by blowing first. 

Some times some of us have to walk into the wall before we acknowledge the wall is there.  They won't take anyone else's word for it.

I have friends that lost their homes and possessions in the recent fires in Malibu, California.  everything is gone.  I can't imagine coming home to find my home completely gone.  That is so bad.  If I can do some pro-active work to prevent it, well, I will. 

I'm trying to avoid the lazy years.  I know it is a pain to turn everything on and turn everything off, but like I said, I hear no marked difference in sound quality more than an hour warm up, and I have been burned twice.

So, nope, not again.

In the case of the Audio Research REF 250 amp, that was partially my fault. I decided to buy "matched" tube sets for the amp from a tube retailer (well known), instead of from Audio Research.  After inserting the tubes, letting them warm up to the specified time period, and biasing the amps, I walked away and one amp blew.  The repair shop told me specifically to never buy tubes from that retailer and always get Audio Research supplied tubed.  Well, yep, I'm buying my tubes from Audio Research from now on.  They will pay for any repairs to their equipment if the damage was caused by their supplied tubes. 


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I might leave  SS on 24/7 but as I live in a condo I have no right to put
other in harms way no matter how small the risk .
To do so with tubes is a outright crime !