Step-Down Transformers (110-120v to 220-240v)

[]-[@n$0Ma☩!©]

Any of you using a step-down transformer to run a 110V *tube* amp on 220-240v power?

If so, what size amp do you have (wattage) and what size transformer are you using?

I am assuming that the 50hz power supply (on a 220-240vsupply) is of no significance so a tub-amp's circuit since it is 100% analog and there are no motors...

 

[garrett]

I used one to power my 50W tube amp and my Pedal Power when I lived in Australia. I don't remember the specs on the transformer, but I'm sure it was way more than enough to handle what I had. Worked great, except the transformer was another chunk of gear to haul around.

 

[justmund]

I used one with my Mark V (90W) and use one with my HXDA (30W), I went with a 1000W transformer in both cases. I seem to remember that 500W would have covered it but yeah, they're like $70 delivered on eBay so went the safe option.

 

[veinbuster]

I used one with my Mark V (90W) and use one with my HXDA (30W), I went with a 1000W transformer in both cases. I seem to remember that 500W would have covered it but yeah, they're like $70 delivered on eBay so went the safe option.

Good idea. The power the amp draws is, of course, much higher than what goes to the speakers.

 

[justmund]

Now that I'm thinking about it, check the fuse rating on the amp. Let's say it's a 3A fuse, at 110V that will be 330W (at which point it would/should blow), so therefore a 500W trannie would be fine.

Just do the power calc (Power=Volts x Amps) and add a bit for a safety margin

 

[justmund]

Found this photo of a HXDA, it says a 250V/2A (500W) fuse but also 250W input power. A 500W would cut it, they usually have circuit protection (breaker) anyway, but me being me, I'd still go a 1000W.

 

[]-[@n$0Ma☩!©]

I already have a 1500 watt step-down transformer. I just don't now what size I *should*be using and was hoping someone had a formula that I could use. I suppose I could just fire up the amp and turn it up until the neighbors complain or something blows up. :tongue:

 

[justmund]

As long as the trannie rating is higher than the fuse rating, you're all good Hans. 1000W or 1500W there won't be any difference