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fired 120V PT with 230V

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  • #1

    fired 120V PT with 230V

    Oh man,

    I got my 5e3 from my ampbuilder today and as I fired it up the PT made weird noise, the tubes shined bright and I got nearly blind by the pilot light...till the fuse blew.
    So §$% happens. I donīt want tell the name of the ampbuilder, because he is a nice guy and makes high quality amps. Heīs going to send me the right PT now.
    So the fact is, that I gave a 120V PT a current of 230V.
    What damages could happend to the amp?
    Tags: None
  • #2
    Nobody has an idea?

    I think I will get a step-down tranny and check if itīs working.

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    • #3
      Hard to tell without having a look inside,but it could have caused a lot of damage or you could have gotten lucky,it depends on how long before the fuse blew.I would have a look inside to see if there is any visibly burnt components,better yet,you should send it back to the "amp builder" rather than have him send you the "right PT now".I have to think you fried the PT primary at the least,but there could be a lot of other damage.If the builder installed the wrong PT,he should make good on it.

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      • #4
        Thank you Stokes!
        First of all I will check the amp with an step-down tranny.
        If it is working like that I will be lucky, but if not I will install the right PT, that wouldnīt be a hard job at all. He will send it to me immediately
        If I had a multimeter I could check the OT, too, but I havnīt.
        The problem is, that sending it back costs will exceed, because of taxes and so on.
        He granted me assistance by an ampbuilder in my country, so I think we will get the baby working...

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        • #5
          I would have somebody that has a multimeter and some tube amp knowledge check that amp out before putting a new PT in and assuming nothing else got cooked.The fact that you dont have a multimeter tells me you dont have the experience to poke around inside that amp,if I am wrong I apologize,but it is dangerous and you could get hurt.There are a lot of components between the PT and the OT,so just checking the OT with a multimeter wont do.If those tubes were supposed to have 350v's on them you put 700v's on them,although it was only a short time things could have fried.Have it checked first.

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          • #6
            You won't get anywhere near twice the voltage on the guts of your amp, because the transformer would limit it by saturating. I bet everything is unharmed.
            "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

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            • #7
              You may not get a full 2x voltage,but you will come close, he likely had a 2amp mains fuse where he should have had a 1amp,not sure of the exact values but a 230v PT would require a fuse of half the value for a 120v PT.So even if he didnt get the full 2x the voltage he got twice the current and many more volts before the fuse blew.I wouldnt trust the PT saturating thereby protecting the rest of the circuit and assume nothing else was damaged,everything didnt light up to blinding levels because the PT kept the volts from going overboard,they obviously did.A PT works on turns ratio,knows nothing about volts.You put in 120v and x amount come out,put in 240v and xx will come out.I think it is more likely that the PT could have survived and something else would have cooked.Have the amp checked out,never assume you got lucky,its supposed to be a brand new amp,the problem was caused by the builder,the builder should absorb whatever costs it takes to get you a brand new amp,which you no longer have.

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              • #8
                Thank you guys for your replies!
                First, I donīt see any burned spots on the wiring and components.
                Then I put the preamp tubes (12AY7 and 12AX7) in my 18W and they work properly. Hey, the 12AY7 in V1 gives a vey sweet sound in my 18W, wich I like a lot!
                I ordered a step-down transformer on eBay to run the amp with 120V.
                Then I will see and hear if the amp has a damage.
                When it fails, it is part of the builder to give me the right support, that the baby becomes 100% .
                He will arrange the support in my country, that is ok, because there will be no long shipping periods.

                Comment

                • #9
                  Steve was right!

                  I tried the amp with a step-down-tranny and there are no flaws, so far.
                  Iīm so glad!
                  But I noticed more 50cycle hum than on my 18Watt plexi and a popping sound when I switch standby.
                  Could be quite normal, because of the different amp design or is it the step-down-tranny?

                  Any idea?

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