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Please buy safe audio gear

amirm

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#1
In my tear down articles, I routinely emphasize safety factors which are often missed. In reviews I also note at times when equipment has regulatory certification or not.

Often the retort is when was the last time something had gone wrong with electronics this way. So I thought I share a recent experience on this front.

I went to hook up a passive speaker to my Purifi amplifier on my desk. As I hooked up the wire, I am hearing sparking sound. I immediately think the speaker terminals are shorted but quick glance indicates they are fine. No spark is visible and at any rate, the amplifier is still off. Yet the "buzzing" and clear and loud sparking sound continues. I immediately reach for the power strip and hit off and the noise goes away.

Guessing that it may be the IEC cable, I touch that and realize that it was not inserted all the way. I pulled it out and smelled it and indeed it smelled like burnt rubber. Pushed it all in and it was fine. The amp is in standby mode and with its switching supply being on all the time, it was causing that sparking.

The reason to tell this story is that it is not the scenarios we can think of that are unsafe, but the ones we can't! I would have never thought of such a fire risk before it happened this way. Imagine if I were not home and this thing was sparking this way for hours on end. And the cord was a non-name one with no fire or safety rating (UL, CE, CSA, etc.).

So please, unless you really have to, buy audio electronics with proper safety regulations. I can't tell you the exact scenario they may be unsafe. What I can tell you is that it can manifest itself per above when you least expect it.

Now I have to go and check to see if that outlet was on Arc Fault breaker and still did that.
 

Fluffy

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#2
Safety is important – and also not to be dumb. This reminds me one time in the army when some stupid officer disconnected an industrial 7 pin power cable with some 400 volts running through it from a generator, without turning the power off first. It made a whole bunch of sparks and the pins became instantly charred. I think we had to have that cable replaced after that. The officer got promoted later on, of course :facepalm:.
 

mansr

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#4
When my professors call me to service scientific instruments the first thing I do is push in the IEC plug into its receptacle. It is amazing how much annoyance this causes.
I wish those things had a locking version. Then again, they're already far more robust than the US power plug. That's one of the things Britain does well. Once inserted, that pound of solid brass yields to no one.
 

pwjazz

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#5
Just today I caught my son riding a bike without a helmet. When I told him to put it on, he retorted that he hasn't fallen all day. Thus ensued some explaining about risk management. It helped that just last week I feel of his skateboard and hit my helmeted head on the concrete.
 
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#6
Good spot @amirm.

This is why the audiophile idiocy of using ridiculous mains cables astounds me sometimes. I have seen numerous examples (some of which were from national shows) where the cables used were pulling themselves out of IEC inlets or plug/receptacles due to their inflexibility or weight. To rub salt in the wounds, Furutech even made a clamp to help stop this but charge you hundreds of $ for the privilege of not burning your house down.

Unlike the US and Canada the use of AFDD’s are not yet required here, at the moment it’s only a recommendation in UK regulations, but is likely to be phased in slowly over future amendments to our electrical regulations.
 

suttondesign

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#7
I note that the RME DAC's have a cute little twist-on locking power plug. I learned the hard way (until Amir helped me out) that if you don't lock it in, it just falls out.
 

restorer-john

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#9
Personally, I don't love IEC power plugs and receptacles. Yes, they can be convenient in certain situations, but a quality captive power lead is my preferred option on HiFi. That said I have a ton of gear with both.

I do however like the clover leaf style earthed version of the classic figure 8 used on many laptop bricks- it's a lovely connector and never falls out.
 

gvl

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#10
Personally, I don't love IEC power plugs and receptacles. Yes, they can be convenient in certain situations, but a quality captive power lead is my preferred option on HiFi. That said I have a ton of gear with both.

I do however like the clover leaf style earthed version of the classic figure 8 used on many laptop bricks- it's a lovely connector and never falls out.
Those are IECs too, just a different type C5/C6 vs. C13/C14. I'm in a pedantic mood today.
 
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#11
I had a similar thing happen with my car's subwoofer a couple years back. The box is pretty cheap and the original connections from back of box to the sub were not very solid. Eventually I was getting sub cut outs I could not explain, but when I finally opened it up I found some nice melted plastic and realized I was very lucky. Replaced with much thicker wire and haven't had an issue since.

I think it's easy to forget how much energy we're dealing with with all of these powerful integrated devices on the market.
 
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#12
Personally, I don't love IEC power plugs and receptacles. Yes, they can be convenient in certain situations, but a quality captive power lead is my preferred option on HiFi. That said I have a ton of gear with both.

I do however like the clover leaf style earthed version of the classic figure 8 used on many laptop bricks- it's a lovely connector and never falls out.
As far as I am aware, there are minimum and maximum withdrawal forces for all IEC inlets. Probably another thing audiophile mains cables would fail on!
 

Xulonn

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#13
One hazard for tube amp fans is the possibility of destroying your amplifier if you power it up with no load on the speaker terminals. Apparently, output transformers don't like no-load conditions and can arc internally. (I know nothing about SS amps powered on with no speaker load, but understand that it is typically not dangerous.)

Knowing about the no-load tube amp hazard, I looked for - and could not find - a comparator switch-box that would switch the inputs to a stereo power amp at the same time as switching the output between my speakers and a pair of load resistors, thereby always presenting a resistive load to the tube amplifier output stage. I just sent a request for quotation to Paul Baldwin of ReelAudio in the UK for a custom box with relays and dummy loads. Follow my progress at THIS ASR thread.
 

gvl

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#14
I have an issue with gear often not having a hard power disconnect these days. If a device is off it must be really off. They can't expect me to pull the power cord or use a power strip with a switch. Pedantic mood again, sorry.
 

JeffS7444

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#15
Aside from ATI, does anyone offer Hypex or Purifi-based amplifiers in safety-certified housings? Ghent Audio product photos show a grounding point on the lower case housing, but it doesn't appear that the rest of the housing is tied to earth, at least I see no indication that the anodizing has been ground away to ensure electrical contact is made with the rest of the case.
 
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#16
If your worried about power, check the mains feed at the back of your house. Over the years the ground settled and pulled our split phase feed until it eventually shorted to the box - then you get real sparks. It's a common occurrence according to the power company.

But yes, a lot of audio gear these days isn't wired safe - in particular the stuff from China.
 

restorer-john

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#17
I have an issue with gear often not having a hard power disconnect these days. If a device is off it must be really off. They can't expect me to pull the power cord or use a power strip with a switch. Pedantic mood again, sorry.
I use 433MHz 10A switched receivers on all the main power points and a remote that can shut individual points or everything off.
 

restorer-john

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#20
There indeed are several locking versions, and at least one that doesn't require any change in existing units. It 'locks' by cleverly clamping the receptable contact pins. Search for 'IEC Lock'.
Wow, that is a beautiful design. Locking the earth on insertion and requiring the slide switch to be pressed to release.

Brilliant. Thanks for posting. :)
 
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