Step down voltage transformer question

[Chaggy78]

Hi guys,
I have recently acquired a Marantz PM75 Integrated amplifier that requires a voltage of 110v @50Hz or 120v @60Hz and being in the UK I have got a step down voltage transformer for it but I used my multi-meter to read the voltage coming out of the transformer and it was 127v AC.
As this voltage is higher than the recommended 110v/120v would this be safe to use with the amplifier?
I thought it would be best to ask for advice rather than risk plugging it in just in case it may damage the amplifier.
Thank you.

 

[davidsrsb]

You can expect the voltage to fall a little under load

 

[Chaggy78]

Thank you for your reply it is much appreciated. I think I might give the step down transformer a try if the voltage will drop a bit under load.

 

[Chaggy78]

Should there be any problem withe the mains frequency as the UK is 50Hz so does the amp require 110v AC at 50Hz instead of the 127v at 50hz that my step down transformer is supplying?

 

[a.palfreyman]

No, if the transformer is rated for 50Hz it will be ok at 60Hz. The problem occurs when you try to use a 60Hz transformer at 50Hz. You then get high saturation currents in the transformer that cause overheating. As it specifies both, it will be fine with either. Your step down output voltage will drop under load as per @davidsrsb comments above.

 

[davidsrsb]

I look at the OP post, which with the lower voltage at 50 Hz implies that the PM75 might have an undersized transformer

 

[Chaggy78]

Thanks for all of your replies everyone. I am not sure if the transformer is rated for 50Hz or 60Hz is there a way to find that out?

 

[Chaggy78]

I am also trying to replace the power switch as it is faulty and was wondering does anyone know what Amperage switch would be safe to use? I have a 3A switch but is that unsafe?

 

[Chaggy78]

On the rear of the amplifier it says 100v 50Hz/60Hz.

 

[davidsrsb]

On the rear of the amplifier it says 100v 50Hz/60Hz.

That is for the Japanese market, that uses both frequencies in different parts of the country

 

[Chaggy78]

Ah thanks David that makes more sense now. Now I just need to replace the power switch but I'm not sure what amperage switch it will require.

 

[Arkless Electronics]

If it's a 100V Japanese home market model then 120V is way too high.

 

[Chaggy78]

In the manual that I downloaded it says: Power requirements - N and T versions - 220/240v AC 50/60Hz and E Version - 110/120/220/240v AC 50/60Hz. I am guessing the amplifier I have is the 'E' Version.

 

[Arkless Electronics]

Still seems like a Japanese home market 100V version to me from the sticker on the back.

 

[Chaggy78]

Thanks Arkless so I will need a step down transformer that will give me 100v?

 

[Arkless Electronics]

Thanks Arkless so I will need a step down transformer that will give me 100v?

yes.

 

[Chaggy78]

Thank you. The 240v - 100v transformers seem hard to find and are quite expensive so that could be a problem.

 

[karma67]

try airlink,its where i bought mine for my jap turntable

 

[Chaggy78]

Thanks Karma67 it looks like a good place to get one and a bit cheaper than one's on eBay.

 

[davidsrsb]

alternatively use a bucking transformer in front of your 240-120 V to drop 240 V down to 200 V
A 20-0-20 would work