american power problem

[turing]

a lent a friend of mine some pedals i made (rebote delay, zombie chorus), and he took them with him to america. he reported them all being unplayable, intermittent, weird oscillations, no sound at all etc. but when he returned them, they worked perfectly (back in britain). he says he used a 9v dc supply, but that the power jack needed some fiddling to stay in.
what the hell could have caused that? is there some compatibility issue with 110volts? might the plane have temporarily knackered those chips? is it simply a question of a duff power jack?
much head scratching from me, any help gratefully received.

[Paul Marossy]

He wasn't trying to use a 9V 50Hz transformer, was he?

[Paul Perry (Frostwave)]

Probably a crap supply.
Were they all on the one box (like a multi power supply?)
Maybe a wrong plug (typically a 2.1 plug in a 2.5 socket, feels right but the inner conductor floats around).
Maybe sucking too much current from the supply, dropped the voltage. Can cause oscillations & weirdness.
I don't think the chips were 'temporarily' knackered, just starved.
I always encourage gigging musicians switching between 115V & 230V countries to take their usual plugpacks, plus appropriate power distribution board, PLUS a 230/115 transformer (if you aren't running an amp thru it, 60 watts should be fine). That way, no danger of reversing voltages etc.
So far as I know, nobody has ever taken my advice.

[turing]

thanks for the help as always guys. so just to confirm...........if i take the power supply that works here, and stick it through a transformer, it'll work fine in america? and is the lower voltage responsible for the insufficient current? as you see i am staggeringly ignorant about the niceties of power.

[deadsnake]

Some countries have a 50Hz line frequency I´m not sure about USA. And others work with 60Hz that could make the diference in electrical appliances. This frequency is the AC frequency of ocilation.

[Paul Marossy]

Power in America is typically 120V 60Hz. What I was getting at it is that if you tried using a transformer designed for 50Hz, all sorts of weired stuff could happen - before the transformer would eventually fail.

[Paul Perry (Frostwave)]

I've never had trouble running USA plugpacks (presumably designed for 60Hz) on our local 50Hz (after stepping down via a 230/115 transformer). Since power transformers are usually MORE efficient (if anything) at a slightly higher frequency, I don't think there would be a frequency related problem.
In fact, before shipping anything to the USA with a USA adaptor, I run it on my 230/115 50Hz transformer.
Apart from mechanical electric clocks, the only time I have seen a frequency problem, was with a pair of barber's clippers (an early design that appeared to have a sprung mechanism, with a resonant frequency corresponding to the 60Hz USA system.. didn't resonate at out 50Hz!)
It's possible that an under-designed power amp designed for 115v 60Hz might have the voltages a bit low on a 50Hz system because of the power transformer efficiency falling. (In aeroplanes, where weight is everything, 400 Hz used to be standard, so the transformers could be itty bitty. As everything goes to switchmode, it's becoming a bit academic.)
Maybe some of the international rock stars here could comment on their experiences!

[gez]

Power in America is typically 120V

And it's double that in the UK, hence the problem...it would have been like running everything from a flat battery if he was using a PSU intended for UK use (apologies if this wasn't the case). 

Had he used one of those step-up thingies you use when you go abroad all would have been well (if only one or two pedals - can't remember the rating of those things).  Failing that he could have bought a US PSU cheaply.

[gez]

it would have been like running everything from a flat battery if he was using a PSU intended for UK use

Actually, probably worse than that as the regulator in the PSU wouldn't even kick in, or would be intermittent...which might account for some of the strangeness.

He could have used batteries! 

[turing]

thanks for all the pointers as ever guys. i was feeling really down about building pedals that couldn't even survive a plane ride, and you know what guitarists are like about having reliable kit. never had to deal with intercontinental power issues before, so it never occured to me to warn him.

[Paul Perry (Frostwave)]

The only bright side, is that he wasn't taking gear from the USA to the UK (or Australia). I've seen a few completely vaporised antique EH units (with those crap tiny mains transformers) that were suprised to see 240V run straight in. "Goodbye Mr Chips".

[gez]

http://users.pandora.be/worldstandards/electricity.htm

(scroll down for individual nation's voltages)

[A.S.P.]

The only bright side, is that he wasn't taking gear from the USA to the UK (or Australia). I've seen a few completely vaporised antique EH units (with those crap tiny mains transformers) that were suprised to see 240V run straight in. "Goodbye Mr Chips".

same happened with partridge-xfmr equipped HiW*tts...