300w enough?

[Paw]

I recently got myself a IIc+ simul head with no export tranny. Over here we use 230 volt, so I'll have to buy a step down transformer for it. My question: Will a 300 watt transformer do the trick?

The amp is 100w so it should do the trick, right? The reason I ask is because I've read about people using 500w and even 1000w step down transformers with their 100w amps. Is this just overkill or are there any sense in it?

Also, I've heard that voltage converters affects the tone in a negative manner..any opinions?

I sent Mesa/Boogie a mail asking if any of their certified workshops in Europe could install an export transformer, but I have not received any answer yet. Does anybody know if this is possible?

All input appreciated.

Thanks!

 

[Elpelotero]

Try looking for authorized repair centers on the Mesa website or buckle down and give them a call. I've sent emails in the past and it takes forever, if not never, to get a reply.

 

[zebpedersen]

100W output means that, unless it's 100% efficient, the input required will be larger. I'd go for at least a 500W tranny just to be sure.

As far as I'm aware the Coliseum series are called the 300 series because they peak at 300W, even though they are 'only' rated at 180W. If that's true, then they would require quite a bit more at the input.

I know yours isn't a Coli, but just using that as an example.

 

[Shep]

Times the wall voltage by the fuse rating!!! So 230volts x 2 amps = 460 watts!!

 

[Shep]

By the way i would check if your fuse is 2 amps it may be 3.5 or something.

 

[hugsy41]

Shep's right.

You need to have the rating on the stepdown transformer an equivalent or higher (best to be higher) power rating than the input power rating of the amp. The input power rating is P=VI, or input voltage x input current. Just because your amp is 100W, doesn't mean it draws 100W. It means it outputs 100W. For instance, I need a 500W stepdown transformer for my 117V Mark V because it draws 117V at 4A = 468 Watts of power. Any less, and the amplifier would not be running to it's full potential, and if you go low enough, will act just like the tweed or variac power options on some models (someone please correct me if I am wrong about this).

As a side note, it's not as critical having more power, just important not to have less.

Hope this helps.

chris.

 

[Paw]

Thanks for replies guys, I really have no clue when it comes to these things.

So I have to times the voltage of the Mark with the ampere to get the right watt consumption? Shep, you told me 230v x 2 amp = 460w, but the amp itself is 117v. Looks like the ampere is 3 on this sucker, so wouldn't 117v x 3 amp = 351w be right?

Under the fuse it says:
1.5A EXPORT
2.5A 60 WATT
3A 100 WATT <------- means it's 100w and 3 ampere?
3A EXPORT 300
6A 300 SERIES

Elpelotero, I've looked for authorized European repair centers on mesa's site, but I can only find US and canadian ones

 

[MrMarkIII]

You just need headroom. If it draws 300 watts out of the wall, typical for a 100 watt amp (uh, Simuls are 75 watts, but whatever), you want the step-up to handle 300 watts at the very least. A 500 watt transformer gives you more breathing space.

 

[mr_fender]

Output wattage is totally different from mains power requirements. Class A amps for example are very inefficient and burn quite a bit of mains power to produce a relatively small amount of output power. Solid State amps on the other hand are very efficient and will require MUCH less mains power to produce the same output power. Using the amp's mains fuse rating is the way to go. If the amp tries to pull any more current than the fuse's rating, the fuse will blow, so the fuse rating give you a good indication of the amps maximum power requirements. Any needed "headroom" is factored into the fuse rating, since manufactures don't want you blowing fuses every time you crank your amp up. If the amp has a US transformer and requires a 3 amp mains fuse, you would multiply 117 volts by the 3 amps max mains current. That gives you 351 watts. A step-down transformer capable of supplying at least about 360 watts of power at 117 volts would power the amp fine. Keep in mind this is RMS watts. Sometimes manufactureres like to list the peak wattage to make their products look better. Power inverters are notorious about this. Peak watts = RMS watts x 1.414, so 360 watts RMS would be about 510 watts peak. It's always a good idea to give yourself a little room for error, so I'd probably go with about a 400 watt RMS (565 watt peak) transformer. Hope this helps.

 

[Paw]

Cool! You people sure know your business about electricity Very, very helpful. Thanks so much!

 

[Paw]

Finally went with a 750w converter to be 110% safe. Thanks again for all input and tutoring