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I have a friend who lives in Iceland, and we've talked about having me restore, build, and/or modify some pieces of gear for him. They use 220v/50Hz I think, but don't take my word for it. What exactly do I need in order to perform this work for him, if anything? Would it make a difference? I will be designing by ear, so if there could be an audible difference, then I don't want to chance it, would rather play it safe. The highest demand thing would probably be a 50w Marshall tube amp, a JCM800 2204 from early 90s. Might also be building him a rack of API Preamp channels.

Voltage converter is all you need. Don't take low wattage ones, they're good for laptops, or/and home audio/video equipment.

Search on ebay

500W should be enough, you can get that below $50 price point. 1000W below $85.

You don't say what voltage your mains is. The frequency is unimportant.

If the units have a voltage selector then you don't have a problem. A lot of amps have a selector on the back for either 220 to 240V, or 110 - to 120V.

If there is no selector then you need some form of transformer. It can be an "auto-transformer", that is where there is only one winding that is tapped for the relevant voltages as you don't need electrical isolation.

Another option is a "Variac", this is an adjustable transformer very much like a pot. It has toroidal winding with a wiper that picks off a proportion of the input voltage, but being a transformer you can go above the input voltage. I don't know if they are available to step up from 110 to 220V though. I don't know how available these are now, I have a couple from years ago that I use very rarely now.

You can use a step up/down transformer with 2 windings but as you are not bothered about isolation that is putting the expense up due the the use of more copper wire.

sinner wrote:Voltage converter is all you need. Don't take low wattage ones, they're good for laptops, or/and home audio/video equipment.

Search on ebay

500W should be enough, you can get that below $50 price point. 1000W below $85.

Thanks! Yeah, I saw those and that they were nice and cheap, didn't know if the solution were really so easy...

deltafred wrote:You don't say what voltage your mains is. The frequency is unimportant.

I live in USA, NJ, and I guess I can really just assume that the house power is 110v, but I've never metered it. I just checked the fusebox and it didn't specify. Next to the fusebox was a box with three switches that was labeled QO load center.

Mains max
50 amps
240V.A.C 3PH
∆120-240V.A.C 3PH.4W

deltafred wrote:If the units have a voltage selector then you don't have a problem. A lot of amps have a selector on the back for either 220 to 240V, or 110 - to 120V.

Yeah I was hinting at that. This may sound paranoid, but I am worried that if I set the amp to use my voltage and then design it to sound good using that, that when my friend plugs it into his voltage line and sets it for a different voltage that it might sound like ass. Paranoid?

One has to accept the potential mains voltage variation really, the tubes might end up a little bit hot or cold but importantly using a transformer does NOT solve that issue

Hides-His-Eyes wrote:One has to accept the potential mains voltage variation really, the tubes might end up a little bit hot or cold but importantly using a transformer does NOT solve that issue

Eh?

Not quite following you there. You have got to plug the amp into approximately the voltage it is designed for, nominally 220/240. That is where the transformer comes in to step up 110/120V if required.

Stabilising supply voltage variations is a whole other topic that I doubt the poster either needs or wants to get into so will just have to accept that the amp is going to be biased differently at the different voltages it is going to be run at (240 or 220).

JakeAC5253 wrote:Mains max
50 amps
240V.A.C 3PH
∆120-240V.A.C 3PH.4W

If I understand USA mains supplies correctly you can have either 110 or 240V depending upon the type of power socket, the 240V being 120-0-120 and used for higher power applications giving 240V swing while still keeping the maximum voltage above ground to 110V. Will someone in the USA correct me if I am wrong please.

If this is the case then you don't have a problem, you have both 120 and 240V so as long as you have the necessary adaptor or fit the correct plug you can run European 220V equipment in the USA.

deltafred wrote:

Hides-His-Eyes wrote:One has to accept the potential mains voltage variation really, the tubes might end up a little bit hot or cold but importantly using a transformer does NOT solve that issue

Eh?

Not quite following you there. You have got to plug the amp into approximately the voltage it is designed for, nominally 220/240. That is where the transformer comes in to step up 110/120V if required.

Stabilising supply voltage variations is a whole other topic that I doubt the poster either needs or wants to get into so will just have to accept that the amp is going to be biased differently at the different voltages it is going to be run at (240 or 220).

I mean the mains voltage is stable but different for different european nations (most notably the UK). So if he's worried about using the PT at a 110 tap might leave him with a slightly different bias point than the 230 tap because the PT isn't perfect, that's a fair point; but using a converter transformer that also might give anywhere between 225-240 is no better.

Hides-His-Eyes wrote: I mean the mains voltage is stable but different for different european nations (most notably the UK). So if he's worried about using the PT at a 110 tap might leave him with a slightly different bias point than the 230 tap because the PT isn't perfect, that's a fair point; but using a converter transformer that also might give anywhere between 225-240 is no better.

After I had posted I thought that was what you meant.

In reality it isn't going to make that much difference, have you ever monitored the mains supply voltage? It's all over the place here in the UK anyway, especially out in the wilds where I live. (I believe you are in the UK also.)

In Europe the voltage is supposed to be 230V +/- 6% so equipment can be used in any country. Yes the bias is going to be affected but you really need to be setting it for your particular supply voltage anyway and that is assuming that it isn't going to change substantially.

No I agree it doesn't bother me, but the way TS was talking I thought he might be worrying about that kind of thing.

Funny story; the EU power constraints were decided as "The widest tolerance that doesn't require anybody to completely change their power architecture"...

Hides-His-Eyes wrote: Funny story; the EU power constraints were decided as "The widest tolerance that doesn't require anybody to completely change their power architecture"...

Yea, change the specs to suit what is already there.

True story. Years ago when I still lived with my parents they were complaining to the electricity company that the voltage varied too much. If you switched the kettle and toaster on together the lights would dim. An engineer came out and metered the supply and said it was fine. They complained again so he came back with a chart recorder and hooked it up to the meter.

A friend was round one night and we decide to test it out. We switched on every power sucking appliance in the house, electric fires, kettle, hair driers, immersion heater, oven, toaster, etc. for a few minutes. The voltage on the chart recorder dropped to about 180V IIRC (it was a long time ago). When the engineer came back he had to admit there was a problem and they changed the transformer outside on the pole (1100V down to 240) which fixed it.

180V? Jesus that's horrific!

The lights did dim a bit, sort of a yellow glow.