Dodgy step down tranny

Well, it would certainly get quite hot at its rated output, but I don't think I'd expect smoke. If it's the same size as the one on the website, it's reasonably large, and it only has to get rid of 50-60W.

A buyer would have a justifiable gripe at the output voltage drop. You don't mention any apparent provision for tap switching, so I assume there's none.

Sylvia.

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Also note that he has a 3000W transformer on his website. Would be interesting to see if this had a 15A plug :)

Perhaps just two 10A plugs ;)

Sylvia.

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The size of the case is irrelevant, they could shove a very small transformer inside you need to see the internal transformer to make such a judgement.

"kreed"

The size of the case is irrelevant, they could shove a very small transformer inside you need to see the internal transformer to make such a judgement.

** Err - the weight might be a good guide.

The unit I have here weighs just under 3.8 kg including the attached lead.

... Phil

I'm assuming the case is as small as they can make it, simply because that reduces the cost, and increases the potential profit.

Also, it weighs 12 kg, so it either contains a metal brick, or has a hefty transformer.

Anyway, Phil has correctly pointed out that I've made a mistake in calculating the heat to be dissipated given the resistance he measured.

Yet I can't help thinking that something that heavy should be able to achieve more than 500W. Perhaps Phil could post its exterior dimensions

- it may simply have been mislabelled.

Sylvia.

Then it's not the same as the 2kW version on the website, which weighs

12.5 kg. Indeed, it has a similar weight to the 500W version.

Perhaps there's a QA problem with labelling.

Sylvia.

**The mass SHOULD be a giveaway. However, I've worked on more equipment than I care to think about, where the manufacturer (usually Chinese) has incorporated large pieces of non-structural steel to increase the mass of the product. I've even seen all-aluminum chassis devices, where steel has been used to increase mass. The first time I saw this done, was with an Onkyo (Japanese) CD player, back in the 1990s. The CD player weighed in at a hefty 25-odd kg. More than half that mass was the result of a large piece of steel bolted to the base plate. Without opening the player, an owner would never realise that it was the reason for all that mass.

Mild steel plate is still less expensive than copper and laminated iron (in the shape of a transformer).

--
Trevor Wilson
www.rageaudio.com.au

"Sylvia Else"

** Funny about the 10amp fuse being fitted ....

Plus a 2kW version of the tranny would not fit in the box.

.... Phil

Seems an odd thing to do with a CD player, given that I wouldn't have thought a consumer would expect it to be particularly heavy - and certainly not 25kg heavy.

Yes.

In this particular case it's become apparent that there's a disparity between the mass of the example Phil has, and the mass of the 2kW model on the website. I suppose the website could just be mis-stating the mass, but anyone who paid attention to it on the website would notice the difference as soon as the transformer was delivered.

Sylvia.

"Stupider than anyone Else on Earth "

** They are two different models.

** FFS - read the OP.

The stepdown I have here is probably several years old.

.... Phil

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You are correct. There is a specified weight in the listing.

This is a pretty good guide as to what to expect in VA rating.

That could just be a consequence of the mislabelling, or perhaps it's not the original fuse. Some people can be quite casual about ratings when replacing fuses - at least it's better than just covering the blown fuse with metal foil.

It seems clear that this is not a variant of the currently offered 2kW model, and that it's not being used in an application that requires anything approaching that, suggesting that the purchaser probably didn't expect it to be a 2kW transformer either.

Any chance of your posting a (link to a) picture of the offending item's front panel?

Sylvia.

Interesting too how the 3kw version seems to have (hard to read) a

32amp breaker on the front panel. Unless they are fusing the secondary with it.

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Also, certain products might have to "feel to be a certain weight" in relation to its physical volume, for the consumer to perceive them to be a "quality" product.

You would know more about it than I would - being in the industry - but I think high end audio would fall into this category ?

**Absolutely. In fact, I've worked on a few Class D amps (that use SMPS) that are quite heavy, where there is absolutely no reason for them to be so.

--
Trevor Wilson
www.rageaudio.com.au

**High end audio is a different world to that which most people inhabit. Perception is more important than performance in most instances.

--
Trevor Wilson
www.rageaudio.com.au

"kreed"

Interesting too how the 3kw version seems to have (hard to read) a

32amp breaker on the front panel. Unless they are fusing the secondary with it.

**Bound to be in the secondary.

The unit I have here has the fuse fitted in the primary cos at 18 amps nominal - the secondary side would need a fuse and fuse holder bigger than is cheaply available.

The toroidal auto-tranny inside looks roughly made and carries no labelling at al.

Dimensions are 120mm dia and 75mm high.

There are just three light gauge, flexible wires coming out.

.... Phil

"Trevor Wilson"

** That is true nearly everywhere.

Especially politics.

..... Phil