Step down transformer bad idea?

[4est]

I meant no offense... It would be my guess that I ran into what J Swensen has mentioned. I have tried several ultra isolation transformers for computers and sources. They all seemed to suck the life out of the music, and I am a big fan of PRaT. As I recall, I have a few cheapies in the garage. Hmm...

We then have to agree to disagree, no problem.

[sandyk]

Be careful with that, it's detailed as an autotransformer. That means there's no isolation, it can be very noisy and any fault could result in a high output voltage.

 

An autotransformer is a single winding with a tap for the output, there's a direct electrical connection. A transformer with a separate primary and secondary winding has a magnetic connection only.

 

I am well aware of auto transformers, and can see no reason why they should be noisy or dangerous if used correctly.

They are used more commonly than the isolated versions.The OP seems to be more interested in safely operating the DAC at it's rated voltage,(100VAC) and less concerned about possible minor gains from using a lossy isolation transformer.

This appears to be one of the few available from ebay that was actually designed to work with Japanese 100V equipment, not U.S. equipment.

[4est]

I have to ask with all of this 120v to 100v discussion, are we sure there is not already a 120 volt tap on the transformer? I bought 100v (grey market?) Stax headphones off of Audiogon many years ago. Although they were intended for Japan, the only difference was they did not include the voltage selector plug and covered it with a plate. Maybe I am daft, but 100v seems the odd duck worldwide, not 120 or 240v. From a manufacturing end, the most practical way if they desire any exporting, is to pull a lead out of the 120v primaries for 100v. I'd scrounge for some info (simply open it up and photo it) on whatever unit and make darn sure there is not already an appropriate tap inside. It is easy to find, and any competent electronic tech could do it. Mostly likely in a non destructive reversible way.

I am well aware of auto transformers, and can see no reason why they should be noisy or dangerous if used correctly.

They are used more commonly than the isolated versions.The OP seems to be more interested in safely operating the DAC at it's rated voltage,(100VAC) and less concerned about possible minor gains from using a lossy isolation transformer.

This appears to be one of the few available from ebay that was actually designed to work with Japanese 100V equipment, not U.S. equipment.

[thesurfingalien]

I have to ask with all of this 120v to 100v discussion, are we sure there is not already a 120 volt tap on the transformer? I bought 100v (grey market?) Stax headphones off of Audiogon many years ago. Although they were intended for Japan, the only difference was they did not include the voltage selector plug and covered it with a plate. Maybe I am daft, but 100v seems the odd duck worldwide, not 120 or 240v. From a manufacturing end, the most practical way if they desire any exporting, is to pull a lead out of the 120v primaries for 100v. I'd scrounge for some info (simply open it up and photo it) on whatever unit and make darn sure there is not already an appropriate tap inside. It is easy to find, and any competent electronic tech could do it. Mostly likely in a non destructive reversible way.

 

Hi 4est,

 

The original OP posted pictures of this specific device in the few first posts. As far as I can tell, it uses a single primary winding. However, that does not mean the device Alice wants to buy does not have preparations for different voltages...

 

Peter

[4est]

Yes, that was my intent Peter.

Hi 4est,

 

The original OP posted pictures of this specific device in the few first posts. As far as I can tell, it uses a single primary winding. However, that does not mean the device Alice wants to buy does not have preparations for different voltages...

 

Peter

[Superdad]

As I pointer out, Alice is in a 230V country, not in the USA as the OP (Tommy tboooe) is.

[thesurfingalien]

Yes, that was my intent Peter.

 

Hi 4est,

 

I mean that Alice wants to buy the exact same DAC, but perhaps specs have changed. Maybe the current owner can make a picture for us to look at. Alice?

 

Peter

[thesurfingalien]

As I pointer out, Alice is in a 230V country, not in the USA as the OP (Tommy tboooe) is.

 

Yes, I am aware of that. However, some equipment have an internal voltage-selector. My cheap-ass Pioneer-amp has an external one with voltages ranging from 100 to 240 volts. But it is a Brazil model, and we have a variety of voltages here...

 

Peter

[alice]

See the photo

[sandyk]

Alice

Your photo shows that you are stuck with using a 100V AC supply if you wish to ensure longevity.

 

Regards

Alex

[alice]

Alice

Your photo shows that you are stuck with using a 100V AC supply if you wish to ensure longevity.

 

Regards

Alex

 

Yup I thought so, now to place an order if we all agree the won't be sound degradation.

[gmgraves]

George: She is in Australia, a 230V country, so stepping down is mandatory.

 

 

Oh, didn't realize that. Yes. if she's in Europe, or other 220-230 volt, 50Hz locale, a step-down transformer is definitely required. Mea Culpa!

[sandyk]

Yup I thought so, now to place an order if we all agree the won't be sound degradation.

 

Given the cost of an isolation transformer in relation to the cost of the DAC, you can always seek out a higher quality isolation transformer at a later date if you feel there is a possible chance of further improvement.

[alw50]

Interesting discussion re transformers ...

 

Just looking at the DAC in question -- is it really a significant saving to bring one from Japan to Aus?

 

Audiotrends in Melbourne have a DA-06 for $A4500 inc postage.

 

From Japan is $A3400 + about $200 postage + GST on the total (ie about $A350) + import/clearance fees (unknown) + transformer.

 

That's already over $4.1K and could be more ...

[alice]

Interesting discussion re transformers ...

 

Just looking at the DAC in question -- is it really a significant saving to bring one from Japan to Aus?

 

Audiotrends in Melbourne have a DA-06 for $A4500 inc postage.

 

From Japan is $A3400 + about $200 postage + GST on the total (ie about $A350) + import/clearance fees (unknown) + transformer.

 

That's already over $4.1K and could be more ...

 

Ok there, I know the intent is right but you really need to google more. Seems like you don't buy much stuff online. The prices you listed don't really match and I will leave it at that.

[sandyk]

Guys

This lady really knows what she wants,(grin) so a general warning...

This applies to Eloise especially, who is one very smart lady.

[StephenJK]

Yup I thought so, now to place an order if we all agree the won't be sound degradation.

 

Here's my take on this. I don't believe that "Alice" is female, "she's" acting more like a young male of our species who's lusting for some obscure and supposedly highly desirable piece of stereo equipment.

 

Male or female, right or wrong, she/he is wasting our time. Buy it, don't buy it. We really don't care. What we do care about is this - stop bothering us.

[Allan F]

Here's my take on this. I don't believe that "Alice" is female, "she's" acting more like a young male of our species who's lusting for some obscure and supposedly highly desirable piece of stereo equipment.

 

Male or female, right or wrong, she/he is wasting our time. Buy it, don't buy it. We really don't care. What we do care about is this - stop bothering us.

 

One could ask, "Who cares what you think?" Alice was looking for assistance and advice. That's one of the main reasons for the Forum's existence. Posts like yours contribute nothing of value.

[StephenJK]

Assistance and advice has been patiently provided many times. The same question has been asked over and over, but the OP is unhappy with the answer. At some point, it does have to stop.

[alice]

I have made my purchase so thanks all for the valid guidance. What I wanted to understand is the effect of using a step down transformer on sound and the general consensus is there isn't any effect. May actually improve the power.

[wilkie366]

On 10/24/2014 at 2:21 PM, One and a half said:

 

There is no sound degradation, only benefit.

 

What happens is the Luxman (like all electronic equipment) draws current from the mains supply in pulses, not nice clean sine waves.

These pulses distort the supply and also add a reactive component to the rest of the network. Reactive components draw real power for their creation and you pay for this.

By using an opposition in the way of a transformer, the current pulses are tamed somewhat and smoothed, instead of being jagged. The amplifier also sees these pulses. The transformer can remove some of the pain, but can't eliminate it, but it's better than nothing at all. There is also a reduction in the noise level between the neutral and ground on the other (100V) side of the transformer. Many people use an isolation transformer for their audio equipment, they are efficient, provide common mode reduction, last for many years maintenance free and reduce the jagged current lumps all in one go.

 

A lot of people have the idea that placing a transformer in front of audio equipment is a bad idea as it restricts dynamics. Well, that's a load of hooey. A transformer is capable of short term overloads about 10s at least 1.25 times its rated capacity, higher still for shorter periods. Depending on protection circuits, you could draw from a standard 10A 240V supply, 2400W x 2 = 4800W for 5s easy, this is more than enough for any transient and far exceeds the output rating of 99% of power amplifiers. No dynamic restrictions whatsoever.

 

The rated power consumption of the DA-06 is 15W at 100V. Current draw is 15/100 = 0.15A. The transformer suggested previously has 1.0A continuous rating, that's 6.7 times the rating of the Luxman. As a minimum derating factor a transformer for this duty should be 60% more than the load. There is plenty to spare.

Hello there, I came across your reply while googling step down transformers for my new Luxman L507Z which I have just bought from Japan (meant for 100V). First off, my apologies for referencing such an old thread, but I'm wondering if you can help me with the step down transformer requirements. The Luxman sends 210W per channel at 4ohms (my speakers are Dynaudio Contour 30i, which are rated for 300W at 4ohms. How big a step down transformer should I be looking at? 1000V or 2000V? And somewhere I read that isolation transformers are better for audio equipment, would love to hear your thoughts on this. I'm in Singapore btw, where we are at 230V and 50hz. Thanks very much!

Bob

[mitch751]

4 hours ago, wilkie366 said:

Hello there, I came across your reply while googling step down transformers for my new Luxman L507Z which I have just bought from Japan (meant for 100V). First off, my apologies for referencing such an old thread, but I'm wondering if you can help me with the step down transformer requirements. The Luxman sends 210W per channel at 4ohms (my speakers are Dynaudio Contour 30i, which are rated for 300W at 4ohms. How big a step down transformer should I be looking at? 1000V or 2000V? And somewhere I read that isolation transformers are better for audio equipment, would love to hear your thoughts on this. I'm in Singapore btw, where we are at 230V and 50hz. Thanks very much!

Bob

according to Luxman L507Z , its power consumption is 350 watts.  Normally  I will choose 350watts x 2 (minimum) i.e 700 watts step down transformers .... for pay safe .. 1000 watts will be good.    

by the way, "How big a step down transformer should I be looking at? 1000V or 2000V? "  I think you meant watts instead of voltage 

[wilkie366]

2 hours ago, mitch751 said:

according to Luxman L507Z , its power consumption is 350 watts.  Normally  I will choose 350watts x 2 (minimum) i.e 700 watts step down transformers .... for pay safe .. 1000 watts will be good.    

by the way, "How big a step down transformer should I be looking at? 1000V or 2000V? "  I think you meant watts instead of voltage 

Hi Mitch

 

thanks very much, super helpful. And yes I meant W!!

 

bob