Stepdown Transformer help

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Thaymz
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Stepdown Transformer help

Post by Thaymz » Wed Jul 26, 2017 7:26 am

Hi all

I live in Australia which uses 240v power and expecting delivery of a US JP2c. My electronics knowledge is rather lacking and hoping someone might be able to provide some help in determining the appropriate step-down transformer.

I currently have the following from when I use to have some other US gear
.
https://www.jaycar.com.au/120w-240-120v ... r/p/MF1080

I'm not sure if this is appropriate for the US JP2C power / current as its a max current of 1.0 amp. Last thing I want is to fry the power in the amp, especially with the warranty not being valid here. Do I need to upgrade to one of the other transformers?

Thanks in advance! Any help is appreciated :)

Lokair
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Re: Stepdown Transformer help

Post by Lokair » Wed Jul 26, 2017 8:44 pm

I am never sure about these things, this looks right. I would send mesa an email asking what they recommend for US gear usage in Australia.

Lok

Thaymz
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Re: Stepdown Transformer help

Post by Thaymz » Sun Aug 20, 2017 1:52 am

As I couldn't wait, I ended up just trying this one out and turned out to be totally fine. A little noisey but that's only cause I also have a few other things in the setup. Plugged straight in there's no additional noise.

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Markedman
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Re: Stepdown Transformer help

Post by Markedman » Sun Aug 20, 2017 9:07 pm

I wouldn't turn it up loud until you get a transformer that can handle more power! There's a 4 amp fuse on the JP2C so your transformer should be more, 110v x 4A = 440 watts of power and that transformer is 125w, not good IMO.
JP2C, Mark llC++ DG, Mark IV-A/B.

Thaymz
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Re: Stepdown Transformer help

Post by Thaymz » Mon Aug 21, 2017 7:09 am

Markedman wrote:I wouldn't turn it up loud until you get a transformer that can handle more power! There's a 4 amp fuse on the JP2C so your transformer should be more, 110v x 4A = 440 watts of power and that transformer is 125w, not good IMO.
Yikes

Thankfully I never use the master above 9oclock. Looks like the JP will be sidelined and until I upgrade the transformer. Time to get reacquainted with the V. Thanks Markedman

Thaymz
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Re: Stepdown Transformer help

Post by Thaymz » Tue Aug 22, 2017 5:38 am

Markedman wrote:I wouldn't turn it up loud until you get a transformer that can handle more power! There's a 4 amp fuse on the JP2C so your transformer should be more, 110v x 4A = 440 watts of power and that transformer is 125w, not good IMO.
Would it make a difference if I had speaker off and using the FX loop to redirect the preamp signal to the V power section?

The JP load is connected through cab clone to my interface.

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Markedman
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Re: Stepdown Transformer help

Post by Markedman » Tue Aug 22, 2017 10:29 pm

You can buy a meter to show you how much power your amp is consuming. They're relatively cheap https://www.amazon.com/dp/B00009MDBU/re ... 6572288073 this is the one I have.
JP2C, Mark llC++ DG, Mark IV-A/B.

Thaymz
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Re: Stepdown Transformer help

Post by Thaymz » Sun Sep 10, 2017 8:25 pm

So an update. I've been advised by Mesa's distributor that the stepdown transformer is not recommended as would run the amp too hot among other voltage related issues.

How much do you think an official transformer change to Aus export would hurt the value of the amp given it's one of the limited editions? I want the amp to work as it should, and doubt I would ever sell it but not sure how I feel about customising a LE models.

baron58
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Re: Stepdown Transformer help

Post by baron58 » Wed Sep 13, 2017 7:37 pm

The distributor is full of bunk.

Keep in mind that the fuse rating on the amp is when it blows....4A at 117v. So the amp at full tilt is not pulling 4A most likey around 2.5 to 3.

That being said you should be able to get a step down transformer no problem rated at 5A.

You can find anything you need here https://www.110220volts.com/up-downtran ... ormer.html

This one will fit your needs nicely https://www.110220volts.com/ac-500.html

I know and have one. I used to build and sell tube amps. And I used this exact model for all my 220/240 amps to test them

bandit2013
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Re: Stepdown Transformer help

Post by bandit2013 » Sat Sep 16, 2017 5:33 pm

I would also add a power conditioner to the 120V line for the amp to eliminate any power spikes or transients. The Furman supplies will shut down if the applied voltage creeps up or suddenly changes. They are just transient filters essentially but they work great for eliminating AC line noise, including ground noise.

Thaymz
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Re: Stepdown Transformer help

Post by Thaymz » Sun Aug 05, 2018 4:06 am

bandit2013 wrote:I would also add a power conditioner to the 120V line for the amp to eliminate any power spikes or transients. The Furman supplies will shut down if the applied voltage creeps up or suddenly changes. They are just transient filters essentially but they work great for eliminating AC line noise, including ground noise.
Hey bandit, I'm currently running the 110v JP into the 110v Furman conditioner (PL Plus II) which then goes into the step-down transformer and into the wall at 240v. This means that I currently the US gear and AUS gear separately through each respective conditioner.

This might be a daft question, but can I route the step down transformer into my AUS Furman conditioner?

JP > 110v Furman (Switch always on) > Step-down > AUS furman conditioner (Use this switch to power everything)

The AUS Furman unit I have is the M10-xe rated at 10amps max.

APEMAN
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Re: Stepdown Transformer help

Post by APEMAN » Mon Aug 06, 2018 2:21 am

Hey there,

I wouldn't recommend to use the step-down converter, because besides the voltages comes the change in frequency.

The lower 120VAC @ 50Hz will result in lower voltages inside of the amp.

The critial point is the heater voltages that come directly from the PT.

You might end up with a never great performing amp, burning a lot of tubes.
(I've been down that road with my recto - it is possible but far from ideal.)

A PT change is the way to go.

Hardy
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Re: Stepdown Transformer help

Post by Hardy » Sat Aug 11, 2018 8:40 am

Thaymz,

I’m in Perth, more or less did the same thing and bought a MKV from the states 7-8yrs ago and use a step down transformer. I’m sure it’s 1000w....haven’t had a problem and hurt it frequently with no issues

I have stacked it up to other MKV’s that are 240v and cant tell the difference.

Rich

APEMAN
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Re: Stepdown Transformer help

Post by APEMAN » Mon Aug 13, 2018 2:17 am

To my ears, PT swap vs. step-down-converter (1000W) was a big shift in tone/feel.

But maybe it is my ears and I'm too audio-hypersensitive. I play in a loud metal-band but start complaining when the bass-drum gets out of tune to my guitar :D

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