Mesa Boogie 110V=>230V

[metalmaster]

Hi I have mesa boogie dual rectifier solo head. I've buy it in US. In Poland I have difrent voltage. I can use transforme to get lower voltage (110V). some amplifiers have power supply transformers with wiring for both voltages (110V and 230V) Do you have some schematics of that transformer? Or do you know how to connect that trafo.

[GeorgK]

I think Mesa's US models do not have 230V taps on the mains transformers. In that case you would have to buy an export models transformer or use a 230V/115V step-down transformer. But be aware that this could be a rather big one - i estimate 250...300VA.
peace
g

[MickeyG]

I am in the same boat.
I have recently purchased a mesa boogie amp from the states and now need to run it in Australia.
It is 100w output with four 6L6 mesa tubes and five 12ax7 preamp tubes.

In Australia the wall outlet is 240 V. 50hz

The back of the Amp states:
120V
3.5A
50-60Hz.
The power lead is earthed.

A local mesa retailer tells me that the circuitry will be different in US models and the local amp tech won't touch it because they are too scared of voiding their "authorized Mesa repairer" status.

I'm looking into a step down transformer- 240v to 120v.
Is a variac a suitable solution?

Will stepping down the voltage from 240v to 120v ( which the amp was made for) effect the performance of the amp.?
What are the pitfalls i should watch out for?

[GeorgK]

I would not recommend using a variac, as an incorrectly set output voltage could damage the amp. 3,5 Amperes @ 120 Volts means that any additional transformer - stepdown or variac - would have to be rated 420VA or more - quite a big one...
IMHO the most elegant solution would be to have the US transformer replaced with an export transformer, any skilled amp tech should be able to do this. I have never heard of any other circuit differences between US and export models. (What should this be good for? Did your dealer provide any information about this?).
An external stepdown/variac certainly affects sonic performance to a certain degree, as mains supply becomes "softer". This might - to a smaller extent- even be true for the original export transformer, as this one of course has different winding parameters than the 120V model.

Greetings, Georg

[MickeyG]

First of all sorry to Metal master if I dropped in on your thread but I hope we can both get the answers we need if we both ask the right questions.

Thanx Georg K for your help.
I got my amp second hand form the states and had it shipped here. I didn't think changing the Voltage would be such a big deal.
I figured that foreign bands would need to do a similar thing whilst touring Aus. I'm sure they would want to use their own amps set to their specs.

The dealer that gave me this information was from a local music shop who sell big brands. Mesa, Marshall, Fender ect. It was a bit cheeky of me to go in the shop and ask questions about amps that cost five times as much as what i payed.

He admitted that he wasn't much of an amp tech and had me a bit worried about getting it working at all and that NO ONE locally would be game to touch a Mesa amp.
I am less convinced.

Now can anyone give me info on the type of transformer (Auto or triac or whatever) I should be looking for?
Maybe someone could suggest particular brands used for this application in the music trade.

[JimW52]

Do not be tempted to use an auto transformer or a variac. What you want is a stepdown transformer rated at > 420VA. A quick look shows that Jaycar has cat no. MF1084, 500W 240 - 115V ISOLATED STEPDOWN TRANSFORMER, which would fit the bill, although not cheap at $219 it's probably cheaper than getting the amp modded.

Jim

[JimW52]

Better still I just found Dick Smith has M1153 Step-Down Transformer 115V 500VA for $178. This might be a better bet as it comes in ametal case with a handle.

Jim

[pinkmouse]

I don't know if it's the same over there, but in the UK site power tools have to use 110V, so big isolating transformers are very common, and pretty cheap s/h. One of those would fit the bill perfectly.

http://www.screwfix.com/app/sfd/cat/...16158&ts=20358

[MickeyG]

Just found a disclaimer on Mesa's website (International service and repairs) stating that the use of step down transformers will void the warranty. I'm hoping they're just covering their *** against people using the wrong transformers or converters.

[pinkmouse]

Hmm, someone should tell sound crews that. I've lost track of the number of US artists who have used traffo's for 110V backline when I toured with them in Europe.