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Discussion in 'Amps and Cabs [BG]' started by man_at_arms84, Aug 12, 2007.

  1. man_at_arms84


    Jun 3, 2007
    Hi there I raised this issue once before but thought I'd start a new thread as developements in information.
    I bought a sunn head a few months ago from the states and imported it here to the UK.

    My problem was converting the power voltage for the amp from 110v to 230v to run here on UK mains.

    I sent off my amp to specialist to see if it was possible to convert it internally.
    They've now got back to me with the nes that it isnt, and to replace the power transformer insinde will cost hundreds.

    So the solution is a step down convertor transfomer.
    Trouble is the amp needs 1800w power needing a converter of that or higher. which costs money. £140 to be exact/

    Machine mart, a construction etc company here the UK sells convertors to use 110v power machinery here in the UK at around £70 or so.
    Many people have told me, "oh you just need a yellow box from mchine mart" so I fugured I coukld save some cash. but when I rang them, the company told me, that they are too "harsh" and "corse" to use for an amp.

    This confuses me as it does the same job. Electricity is electricty no?

    would I be safe using this to convert the voltage for my amp or not?

    heres the machine mart convertors.

    And heres the company that will cost me £140.


  2. Petebass


    Dec 22, 2002
    QLD Australia
    I'm not expert, but I was able to pick the brains of one a few years ago. A quick background story first..... a massive storm took out our power for several days. I the meantime, I enquired about hiring a generator to keep my fridge and essential appliances running. That's when I found out that some electrical machinery is happy to use "rough & ready" electricity, power tools being the obvious example. However things like fridges, microwaves, and probably music amplifiers should only be used with a generator that has a "surge arrestor" to smooth out the delivery of the power supply and to protect against any spikes or drops in voltage.

    One of your links didn't work, and the other didn't have any specs so I can't confirm or deny if I'm on the right track. But it did link us to a power tools company. I'm only guessing so if anyone else can add to this, that'd be great.
  3. One Drop

    One Drop

    Oct 10, 2004
    Swiss Alps
    I was told to use a two step transformer with circuit protection (i.e.fused) for amps. I got one from TAD in Germany for about 1/2 the price you were quoted, but it's rated for 1000AV.
  4. Indiana Mike

    Indiana Mike Supporting Member

    Nov 18, 2005
    actually you'll need a step UP if going from 110vac to 230vac.

    do an american google search for step up transformers and foriegn power converters
  5. The Machine Mart probably isn’t regulated, Hard to tell with no specs.
    Which would be close enough for power tools but not electronics.
    Best bet is to go with something that is guaranteed to work.

    It would be a shame to damage your Sunn just to save 70.

    Indiana Mike; re-read the post it’s a US built Sunn in the UK.

  6. Indiana Mike

    Indiana Mike Supporting Member

    Nov 18, 2005
    got me !

    if you need 1800 watt I would oversize 125%



    Power Bright VC2000 - 2000 Watt Step-Down Voltage Converter
    Step-down Voltage Conversion?

    This Power Bright VC2000 Step-down Voltage Converter is for use in the UK to power electrical equipment from the USA. What it does is convert UK 220 - 240 volts to US 110 - 120 volts. The output is pure AC and the voltage converter can be used with all appliances rated 0 - 2000W. This voltage converter will take US two pin and three pin plugs.

    Power Bright?

    For a while we have been struggling to find reliable heavy duty voltage converters at a reasonable price. We are extremely pleased to have become distributors of the Power Bright range. Our testing of the Power Bright products has shown them to be both robust and reliable. Coming soon, Power Bright Step Down converters with Euro plugs fitted and Power Bright Step Up converters with US plugs fitted.

    What Can I Use It With?

    Everything with a rating of 2000 Watts or below (although in practice it is a good idea to allow some margin for error). This would include just about everything from computers, TVs and Hi-fis to most heavy duty industrial equipment (check rating to be sure). This is a heavy duty desktop voltage converter and it weighs nearly 16KG.

    Simply plug the voltage converter into a UK socket and plug the US plug into the voltage converter.

    Step Down and Step Up?

    We sell this primarily as a Step Down voltage converter as it is fitted with a UK 3 pin plug. However, all Power Bright converters are very versatile and have the ability to also be used as step up converters (to allow the use of UK equipment in the US). If you wish to do this, all you need to do is change the jumper switch at the back of the converter and fit an adapter to the power plug (we supply an adapter free with each Power Bright voltage converter).


    With fuse protection
    Ideal for use of US 110 - 120V two or three pin appliances in the UK
    Has two spare fuses
    Free PB26 plug adapter - worth £3.99
    Pure AC output
    Can also be used as a Step Up converter.
    Dimensions - 180mm wide x 250mm long x 140mm high
    Weight 15.8Kg

    For more voltage converters please click here.

    For electrical plug adapters please click here.


    One year manufacturer's guarantee.


    This is the price you pay. There is no V.A.T. Or delivery charge to add within the UK.

    Spare Fuses

    Five Pack of 20 Amp fuses, for use with Power Bright VC2000 - £2.99
  7. Bryan316

    Bryan316 Inactive

    Dec 20, 2006
    He's stepping his country's 230VAC DOWN to 110VAC for his amp.

    And electricity is NOT electricity. There's all kinds of opportunities for problems. Fluctuations in voltage, dipping down into brownout danger, bad grounding, external RF noise, current sags because of under-rated steppers, not to mention thermal overloading of weaker residential appliance steppers.

    For a musical instrument or amplifier, you'll want a quality transformer. Think about it... you're about to use one badass amp. No doubt it cost you a pretty penny. Why would you want to go cheap on powering your gear? That's a terrible way to allow all kinds of opportunities for failures.

    And get a Furman power conditioner with a voltage readout also. That'll assure that your stepper transformer is actually giving you the voltage your amp needs. Turn on the Furman first, get a voltage reading, then turn your gear on if it's safe.
  8. Indiana Mike

    Indiana Mike Supporting Member

    Nov 18, 2005
    yep I already acknowledged my mistake
  9. man_at_arms84


    Jun 3, 2007
    Thanks very much for that link. That sounds great.
    I'll defo consider that one.

    Yeah I kind of figured that after asking around too. your post has assured me of it too! I know nothing of electronics, I wont pretend to, hence me posting.

    Im completey broke, from having the worst luck with gear (spent over £2000 this year so far fixing ****, after this I have a speaker repair job of £227 after lending somebody a cab) and I tour a fair bit, which is why I was trying to save money.
    end of the day I dont want to be even more broke when I blow my amp from using the wrong transformer!
    So I guess I'll have to fork out the cash!

    Where can I get this furman power conditioner and how much?

    Thanks very much for all the info!
  10. TrooperFarva


    Nov 25, 2004
    New City, NY
    I think you're better off swapping out the power transformer in the amp. It's more expensive, but I'd trust it a lot more.

    If you loaned someone a cabinet, and when you got it back, the speaker was broken, why do you have to pay for it?
  11. A9X


    Dec 27, 2003
    The machinemart devices linked in the first post are likely just step down transformers, no more complicated or likely to add noise, line distortion or other artifacts than the power transformer currently inside your amp is. Note the copy on the linked page; "These general duty site transformers" so they're transformers. The 'site' part would be because they're in tough little casings to protect them from the hazards of construction site work.

    Buy oversize, as was suggested by 20% or more as this will mimimise additional voltage loss from having the transformer in circuit. Remember though, that whilst your amp may be capable of say, 1000W, even if you clip it on peaks, the average power used throughout a song will be much lower, probably by 10dB, so you'll be using about 100W average. Buy the 2250VA model when it's back in stock.
    Don't waste your money on Furman 'line conditioner' (wallet drainer). If concerned about voltages at gigs, buy a $10 multimeter from somewhere and use that. Takes no rack space and can be used of other things too.
  12. +1

    You also have to be aware of the AC frequency with stepdown transformers. Not sure what it is in the UK - but for Aus. some amps have issues with 60hz/50hz.

    Also- you wont have to carry around a boat anchor if you convert the internal transformer.
  13. TrooperFarva


    Nov 25, 2004
    New City, NY
    It's not that I fear the transformer can't handle it, but as in some other situations, it's just one more thing to go wrong. But also, as someone else said, those transformers are designed for power tools, etc., whose performance isn't noticeably impacted by power quality. Also, if you buy a step down transformer, you'll have 2 transformers in a row, when you only need 1. Lastly, if you (or he, rather, since it's not your amp) swap out the power transformer, you'll get most of that money back in resale if you decide to part with the amp later.

    But that's just my view on it. Certainly a step down transformer is a viable option, and likely won't cause problems, but I figured I'd throw my $0.02 into the mix.
  14. A9X


    Dec 27, 2003
    The person the OP spoke to is an idiot. There is no issue at all in doing this and the step down TX will add no noise, garbage or waveform distortion if specced and used correctly. Actually, it will act as a low pass filter, and remove some line crap before it gets to the power amp.
    Switch mode type step/down converters may be an issue for audio, but fine for power tools etc. Same for low quality generators.
    How many transformers are in series between the power station and where you plug into the wall? With an overspecced step down, and an amp that is not drawing it's rating continuously, there will be no issue.
    I agree with this, but as the OP stated the cost was very high. I'm an EE so I could do it myself, even if I had to spec the PT and have it made locally. Still reasonably cheap as labour costs are zero, I know where to get the part made cheaply. The OP has to pay a tech and pay the (usually) exorbitant spare part cost from the manufacturer. having done similar exchanges in the past, it can be extremely expensive to do with factory parts.
  15. tadawson


    Aug 24, 2005
    Lewisville, TX
    The last thing the power sees before it hits your house is a transformer - and this is just another transformer. Neither is regulated, and neither needs to be . . . transformers "transform" voltage and current by a fix, invariable ration, so what comes out is as accurate as what goes in . . . IE, if the regulation out of the wall was good enough, it will be here too . . . .

    As others have already stated, you go through numerous transformers and voltage conversions on the way from the generator to you, and so one more is irrelevant. Not sure about in the UK, but in the US, the power on the pole outside your house is about 2100V, IIRC, and the transformer on the pole takes it down to 120 for you . . . . and the voltages on the main "hi tension" lines coming into your city may be as high as 750,000 or more . . . once again, all via transformers . . . . .

    Bottom line is that a transformer is a purely passive device - it can't introduce things into the power that it didn't get in the first place. The only risk is if you undersize it, and it either can't hold voltage, or it overheats . . . . the same issues that happen in the power grid under heavy load . . . (brownout, anyone?)

    The only comment I saw that may bear closer inspection is the 50Hz/60Hz difference . . . . a transformer CAN'T correct that . . .

    - Tim
  16. man_at_arms84


    Jun 3, 2007

    I rang fender who made the amp in the 90's.

    the transfomer costs £400! (around $800!!). Thats before a tech fits it! thats nearly as much as I paid for it in the first place!

    So Im thinking i'll be going down the Stepdown convertor route!

    Just a little more asking around to make sure I do it right and dont blow anything!

    I'll let you now what the amps like when I get it going.

    Now I just need to fix my speaker cab! ha.
    (I usually use a 4ohm 4x10 and a 4 ohm 1x 15 but I have a great marshall 4ohm 4 X 12 to use at the mo') .

    Cheers for all the help guys, much appreciated. :)
  17. A9X


    Dec 27, 2003
    When speaking to stores etc, please use the expression 'stepdown transformer' so there is no confusion with switcher based devices and you get what you need.
  18. man_at_arms84


    Jun 3, 2007
    will do. Cheers for the heads up.

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