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Using an US imported amp in Australia


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Hello all! Thanks in advance for your help.

 

I purchased a Yamaha A-S301BL from Amazon USA. It arrived today and I plugged it into my 240V Australia home's power (yes big mistake!) without a step down transformer, just a simple plug adapter.

 

There was a white flash when i switched it on and I can see that the glass fuse has blown due to the excess power. The amp is not working. Please could I get some advice on which route to follow:

 

1 - Buy a step down transformer and a replacement fuse and try again (may take a couple of weeks for these bits to arrive)

2- Return the amp to Amazon for a refund (must be returned within 11 days from today)

 

I am concerned that it has more damage than just the fuse, and if i go with option 1 and it doesn't work I will be left with a broken amp that I cannot return. I can't see any more visible damage that the fuse itself.

 

Thank you!

 

Sam

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That's a fair question. Do they perhaps have a responsibility to inform me that this isn't compatible with Australian power when exporting from the US?

 

I accept responsibility that I should have researched this myself. It didn't occur to me as I've used a lot of devices from Europe/UK with a simple plug adapter.

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I agree that expecting a refund seems beyond plausible.  You may be lucky with replacing the fuse but if not, an expensive lesson - and why supporting your local economy is usually recommended.

I hope it works out ok.

To your second point - UK is 230v so most appliances will work fine.  But US/CAN is completely different.

Edited by glennb99
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That amp has a switching mode power supply, and a conventional power supply (with that big transformer). A couple of things jump straight out:

 

- the transformer primary has a single winding - it seems that it can not be used with 230/240V AC. This seals it - the amp can not be converted to 230/240V.
- the fuse is 6A/125V (which translates to 3A/250V). That is a fair amount of current, i.e. quite high for a fuse rating. In other words, just before the fuse blew, it is quite likely that you damaged (at least) a bridge rectifier (located on an SMPS) and possibly damaged the transformer primary winding, or at least blew a fuse (inside the transformer that is usually used in series with this winding and is quite hard or impossible to replace).

 

I recon the damage is most likely substantial.

 

Using a step-down transformer is usually not a good idea - it hampers the dynamic range.

 

However, it is up to you if you want to try a step-down transformer. If you do want to try, replace the fuse with 3A / 250V rating.

 

Try to return it and see what Amazon's gonna say.

 

Good luck.

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Quality stepdowns are a bit expensive, try to borrow one or maybe a variac and replace the fuse and pray. The unit has a diagnostic mode but doubtful you will get that far. Second the substantial damage possibly cost prohibitive to repair. First step would be to continuity check the primary windings of the transformers, both have thermal fuses. With any luck you've only blown the subtrans supply, the main transformer is only enabled after basic health checks.

 

EDIT: The blown fuse feeds the large transformer, unplug that connector with the thick yellow and grey wires then continuity check between these wires, expect open/OL.

Edited by mbz
Fuse
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Thank you everyone, I will try connecting to a stepdown with a 3A / 250V Fuse. If this doesn't work then it would seem that the damage is too substantial to repair.

 

I'll give an update here once I've tried. Thanks again!

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3 hours ago, knightsam said:

...I will try connecting to a stepdown with a 3A / 250V Fuse...

 

Why? If you're using a stepdown transformer I would have thought you use the same fuse as the one you fried. Only a new one, of course.

Edited by brodricj
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4 hours ago, knightsam said:

I will try connecting to a stepdown with a 3A / 250V Fuse. If this doesn't work then it would seem that the damage is too substantial to repair.

 

You sure you want to do that yourself? 

 

Lets see what the manual says. I know we are Aussies blokes and can do anything and  don't ever read the manual  but maybe we don't have to keep making the same kind of mistakes?


 

Quote

 

Page i

Use the voltage specified for this product. Using an incorrect voltage may result in fire, electrical shock or damage  to the product

 

 

Dam. Would have been good to read that before plugging it in. Lets see if there's anything else on Page one to prevent further issues. Maybe this:

image.png.8935eef618c34fb478df01333f137999.png

Legirl disclaimer:   no responsibility is accepted for ozzie blokes killing themselves or burning down their homes  by not reading the manual and/or following any encouragement of other ozzie blokes on SNA that reinforces the myth that all  ozzie blokes can do anything and are immortal

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The comment from Extreme_Boky explained that a 3A / 250V Fuse is the same as a 6A / 125V Fuse. The 3A fuses are widely available in Australia, I would need to import a 6A/125V Fuse.

 

Would this cause an issue if used with the step down transformer? Thanks!

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4 hours ago, knightsam said:

The comment from Extreme_Boky explained that a 3A / 250V Fuse is the same as a 6A / 125V Fuse. The 3A fuses are widely available in Australia, I would need to import a 6A/125V Fuse.

 

Would this cause an issue if used with the step down transformer? Thanks!


Only if something goes wrong - which is kind of why the fuse is there in the first place.

 

May I suggest not doing anything yourself? Going wrong here means whoever inherits the amp has to deal with it…

Edited by TheBlackDisc
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1 hour ago, knightsam said:

The comment from Extreme_Boky explained that a 3A / 250V Fuse is the same as a 6A / 125V Fuse. The 3A fuses are widely available in Australia, I would need to import a 6A/125V Fuse.

 

Would this cause an issue if used with the step down transformer? Thanks!

 

Sam, can I suggest - for your own safety's sake - you henceforth only buy hifi equipment from reputable stores in Australia ... who will supply you with gear which will work in Australia.

 

As, unfortunately ... you don't seem to have a clue about electricity.  :classic_sad:

 

If you use a 240v-to-110v step-down transformer then you will be feeding 110v to your amp.  In which case, the fuse it should have is the one shown on the PCB - 125v/6a.  (Not 250v/3a!)

 

But if you are going to again try feeding 240v into the amp ... then the fuse that needs to be installed is a 250v/3a one.

 

Andy

 

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For test purposes a 3A or 5A fuse will be fine remember the current draw/fuse rating will be linked to full power output. Simply checking for any sign of life.

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52 minutes ago, mbz said:

Simply checking for any sign of life.

On the amp? Or on @knightsam? Depends on when you do the checking, now or after he fiddles with things about which he apparently knows SFA?

 

Seriously @knightsam, go find a qualified technician to look at the amp. We, the collective membership, would rather you fork out a few more $$$$ to find out if the amp is trash or treasure than we would start looking at your post count and begin wondering why we've never heard from you again.

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@knightsam  If you don't know anything about electrical and electronics repair, please spare a thought for the poor tech that may have to try and fix the thing, if you do decide to get it repaired. You fiddling around in the bowels of the amp is only going to complicate repairs.

 

Personally, when I was in business, I would refuse to take on jobs that the owner has "had a go at" himself.

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I looked into the service manual. The mains transformer comes either as a 110/120 model, or as a 230/240 model. 

 

The fuse rating is 6A/125 for the 110/120 model; 4A/250V for the 230/240V AC model.

 

@knightsam  

 

I suggested the 3A/250V fuse because you can not get the 6A/125V in Australia. However, it seems that you are not electronics/electrics savvy - hence, I strongly suggest that you try to return the product to Amazon US and see what they have to say.

 

If, however, you decide to insert the new fuse and use a step-down transformer, please note: You will be playing with lethal voltages that can cause severe harm or death, as well as damage or fire to your equipment and/or electrical installation in your household. 

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20 minutes ago, Extreme_Boky said:

I suggested the 3A/250V fuse because you can not get the 6A/125V in Australia. However, it seems that you are not electronics/electrics savvy - hence, I strongly suggest that you try to return the product to Amazon US and see what they have to say.

 

It's the nominal current draw of the equipment at the stated supply voltage that decides the current rating for the fuse. So if you fit a 3A 250V fuse in place of a 6A 125V fuse (when connected to a 125V AC source), it will blow, because the amp is trying to draw the required 6A as per specs. A 6A 250V fuse will still rupture within the parameters, even when used with a 125VAC supply.

Edited by bob_m_54
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The fuse for the A-S301 amplifier model is specified as:

 

6A/125V   or    T2.5A/250V 

 

I can not tell if the first fuse (6A) is a fast-blow fuse (there's no T in front of its specifications but still, I am unsure....). From my experience, it will have to be a fast blow.... 6A is insanely high.

 

In general, the fuse should protect equipment during nominal operation; i.e. if there is a problem 99.99% of the time amplifier is on - not only during the power-on / power-up. 

 

Oversizing the fuse to allow for capacitors charging current surge during a power on - is a wrong approach. This fuse would then provide no protection during normal operation. The surge protection, ideally, should be handled by other means that will limit the initial current. Furthermore, in this particular case, we have 2 X 12,000uf of storage..... so the surge current is not going to be big.

 

My suggestion to go with a 3A/2550V fuse was based on the above - mostly on the manufacturer's recommendation to use a slow-blow 2.5A/250V fuse. I admit this is with a 240V transformer and with a 240V mains supply. 

 

Anyway, I believe that the 3A/250V slow blow fuse will suffice if the amp is still okay - even with a transformer specified for 110/120V mains and even with a step-down transformer. 

 

3A fuse will also provide a bit of a safety margin in this case (inexperienced person playing with fuses and mains voltages). This is why I did not suggest a 4A/250V fuse. 

 

You are more than welcome to tell @knightsam EXACTLY what fuse rating you suggest to be used in this particular situation.

 

 

 

 

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6 hours ago, Extreme_Boky said:

 

The fuse for the A-S301 amplifier model is specified as:

 

6A/125V   or    T2.5A/250V 

 

I can not tell if the first fuse (6A) is a fast-blow fuse (there's no T in front of its specifications but still, I am unsure....). From my experience, it will have to be a fast blow.... 6A is insanely high.

 

In general, the fuse should protect equipment during nominal operation; i.e. if there is a problem 99.99% of the time amplifier is on - not only during the power-on / power-up. 

 

Oversizing the fuse to allow for capacitors charging current surge during a power on - is a wrong approach. This fuse would then provide no protection during normal operation. The surge protection, ideally, should be handled by other means that will limit the initial current. Furthermore, in this particular case, we have 2 X 12,000uf of storage..... so the surge current is not going to be big.

 

My suggestion to go with a 3A/2550V fuse was based on the above - mostly on the manufacturer's recommendation to use a slow-blow 2.5A/250V fuse. I admit this is with a 240V transformer and with a 240V mains supply. 

 

Anyway, I believe that the 3A/250V slow blow fuse will suffice if the amp is still okay - even with a transformer specified for 110/120V mains and even with a step-down transformer. 

 

3A fuse will also provide a bit of a safety margin in this case (inexperienced person playing with fuses and mains voltages). This is why I did not suggest a 4A/250V fuse. 

 

You are more than welcome to tell @knightsam EXACTLY what fuse rating you suggest to be used in this particular situation.

 

 

 

 

Nope, still wrong.. the amp will still want to draw whatever it is rated to draw, whether through a 250V (I'm guessing you didn't actually mean 2550V) fuse, or a 125V fuse. Go with the rated Amp spec, but but in a 250V fuse.

 

The manufacturers recommendation is for a fuse rating at the voltage of the supply to the amp. ie 6A @ 125VAC (if that's what the manual says, I haven't read it)

 

You blokes really shouldn't be playing with mains voltages...

 

Edit: Here's a bit of info to explain Voltage Ratings of fuses.

 

Quote

VOLTAGE RATING: The voltage rating, as marked on a
fuse, indicates that the fuse can be relied upon to safely
interrupt its rated short circuit current in a circuit where the
voltage is equal to, or less than, its rated voltage

 

https://www.littelfuse.com/~/media/electronics/application_guides/littelfuse_fuseology_application_guide.pdf.pdf

Edited by bob_m_54
more info
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23 hours ago, andyr said:

But if you are going to again try feeding 240v into the amp ... then the fuse that needs to be installed is a 250v/3a one.

I'd say that if a 120 volt amp lost the smoke when plugged into 240 volts then the correct fuse for trying that again is "none".:)

 

@knightsam

1. The manual states that the "general" model is 120v-230v switchable. If there is not a switch on the back then you probably have a 120v model only.

 

2. Really, take it to a tech and see if it's worth repairing. They may even be able to source an appropriate internal transformer if it is. If they can't, then an external step-down transformer will work fine as long as it has the capacity that the amp deserves. I ran a Canadian amp on a step-down for years in NZ without issue.

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I wouldn't muck about with it unless you really know what you are doing (and your very first post indicates that you don't).

 

I would take the amp to a reputable repairer for an assessment of the damage and a quote for repair. You will spend a certain amount of money for his time and effort, but at least you will know where you stand.

 

PS: I know probably as little about electronics as you do (except that you don't plug US 120V equipment into Australian 240V sockets and hope for the best!), and there is no way I would be mucking around with the internals of an amp.

 

 

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I would go with a slow-blow 3A / 240V AC fuse to test the amp... which is probably faulty. If it blows immediately with a bang.... the map is faulty. If it works okay, but blows the fuse later, I'd increase the fuse rating to 4A/250V.

 

The fuse is there to protect the big transformer. The DC voltage rails used for the amplifier modules are probably close to plus and minus 60V DC (capacitors are 12,000uF / 71V DC). With 240V AC being applied to the amp, these two rails were probably sitting at close to plus and minus 100V DC or higher for a brief moment, which most likely took out a lot of transitions on those AMP PCB's...

 

 

 

Edited by Extreme_Boky
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59 minutes ago, bob_m_54 said:

You blokes really shouldn't be playing with mains voltages...

 

 

I would go further and suggest we stop offering advice, other than to get it checked by someone qualified.   Far too much misinformation flows on the internet and someone's gonna get hurt, or sued. :(     Maybe should even be a forum rule ?

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3 minutes ago, GregWormald said:

I'd say that if a 120 volt amp lost the smoke when plugged into 240 volts then the correct fuse for trying that again is "none".  :)

 

Very true!  :thumb:

 

3 minutes ago, GregWormald said:

1. The manual states that the "general" model is 120v-230v switchable. If there is not a switch on the back then you probably have a 120v model only.

 

Shirley it's possible that there might be an internal switch?

 

3 minutes ago, GregWormald said:

2. Really, take it to a tech and see if it's worth repairing.

 

^   ^   ^  what the man sez!  :)

 

3 minutes ago, GregWormald said:

They may even be able to source an appropriate internal transformer if it is.

 

I don't see why there is any problem at all, in finding an appropriate Oz traffo as a replacement?  The US traffo will have a '110' or '120' volt primary winding ... and the secondaries will be 'X' volts - such as 30v.

 

Harbuch make 240v traffos with a variety of (dual) secondary windings - see here:

 

image.png.341a1ff6a824b678b6c51c13082efb65.png

 

 

So I would've thought traffo replacement would be a relatively easy procedure for a tech.

 

Andy

 

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