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  1. #1
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    Default amplifier building and safety standards

    are there standards to conform to which are enforced by any environmental or work/leisure safety authorities??

    i have heard there are standards in Aust. which make it extremely difficult to build and sell electronic gear such as amps etc

    i have not found anything so far on the web
    ray c
    dunno what's more fun, buyin' the tools or usin' em'

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  3. #2
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    There are electrical safety standards which must be complied with and they tend to require certain test procedures and certificates in order to comply....none of which is cheap.

    However, that said, there's no shortage of amplifer manufacturers in Australia - Aspen, Redgum, Halcro, Burson, EHT, ME, Supratek....(although the last two are late & lamented) and quite a few others. There are even more kit suppliers from Jaycar/DSE/Altronics and on into the stratosphere.

    What tends to hinder & stop them is not the electrical standards but the complexity and economics of manufacturing, marketing and exporting....
    Ours is not to reason why.....only to point and giggle.

  4. #3
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    Quote Originally Posted by old_picker View Post
    are there standards to conform to which are enforced by any environmental or work/leisure safety authorities??

    i have heard there are standards in Aust. which make it extremely difficult to build and sell electronic gear such as amps etc

    i have not found anything so far on the web
    Have a search for EMC standards, EMC testing

    (E
    lectroMagnetic Compabability)

    In a nutshell, to sell equipment commercially, you will need to prove compliance with the relevant EMC standards (eg "C-tick" in Australia, "CE" etc.).

    EMC testing and certification can easily cost $10,000 per item - and is only valid for items constructed identical to the specimen tested. Change one part and you may need to redo the test.

    BTW, the tests are a two way thing. Not only do you need to prove that your equipment won't interfere with other equipment (the "interference" testing), you also need to prove that your equipment isn't overly sensitive to external interference ("susceptibility" testing).

    The exact testing and certification required will depend upon what type of equipment it is, and the intended market

  5. #4
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    Valve amps only have to pass one test......the fried egg test. You break an egg on top of the amp housing and if its not fried in 10 minutes the amp doesnt meet the standard.
    Whatever note you blow youre never more than a semitone away from the correct one....(Miles Davis)

  6. #5
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    Quote Originally Posted by SilentButDeadly View Post
    There are electrical safety standards which must be complied with and they tend to require certain test procedures and certificates in order to comply....none of which is cheap.

    However, that said, there's no shortage of amplifer manufacturers in Australia - Aspen, Redgum, Halcro, Burson, EHT, ME, Supratek....(although the last two are late & lamented) and quite a few others.
    Just a nit. ME is back in production, albeit in a smaller way than before. The only product presently being manufactured in the ME850. There is a reasonable chance that a smaller model (to replace the ME550-II) will be released before the end of the year. Sometime next year, if all goes to plan, a replacement for the ME1400/1500 will be released. All but the replacement for the ME550-II (code-named the ME580 ATM) will be manufactured totally in Australia. The ME580 will probably be substantially (if not totally) manufactured you-know-where, but to exacting standards expected by ME customers.

    For more information:

    www.me-au.com
    Last edited by Zaphod; 1st June 2009 at 02:49 PM. Reason: Brain fart

  7. #6
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    Default Australian Standards

    Quote Originally Posted by old_picker View Post
    are there standards to conform to which are enforced by any environmental or work/leisure safety authorities??

    i have heard there are standards in Aust. which make it extremely difficult to build and sell electronic gear such as amps etc

    i have not found anything so far on the web
    As far as the actual AS are concerned, you may have to conform to the following;

    GENERAL AS/NZS 3100: Approval and test specification - General requirements for electrical equipment
    AS/NZS 3350.1: Safety of household and similar electrical appliances - General requirements
    AS/NZS 3350.2.1-98 Series: Safety of household and similar electrical appliances
    AS/NZS 60065: Audio video and similar electronic apparatus - Safety requirements
    AS/NZS 60335.1: Household and similar electrical appliances - Safety - General requirements
    AS/NZS 60335.2.1-98: Series: Household and similar electrical appliances


    none of which are cheap to purchase!

  8. #7
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    With not too recent changes to electrical licencing laws nationwide. It is almost imposible for a hobyist to construct anything powered directly from a 240V source.
    Anything 240V is licenced work.

    This is why a great many elecrtonic projects and a lerge amount of small electronic commecial items are now powered of plug packs.

    As for the standards
    The only ones that are realy enforcable are the electrical compliance standards, in particular AS3100.

    The electromagnetic compliance issues are largely exempt for prototypes.
    If the item has an analog power supply and is a linear analog device that can not produce RF or switch heavy electrical such as a light dimmer or a switch mode power supply the C tick certification is relativly easy.

    Now the sticky part is the speaker output of high power or voltage amplifiers.
    In the EU high power amplifiers can no longer have binding posts for outputs because the voltages can be above ELV (35 V AC). so the amps have to have a touch proof connector such as a speakon or shrouded banaba plugs.
    Things arent that fussy here ... YET.

    There are further... implied requirements.
    Because of the electrical safety laws currently in place, most manufacturers have changed the way the do their electrical wiring inside items.

    In the past it was common to see exposed 240v connections inside an amplifier such as the back of the mains plug, fuse holder, switches transformer terminals and so on.
    These days all that stuff has to be insulated, because if it wasn't taking the lid off an item would be clasified as "LIVE WORK" which requires stringent work methods.
    Because anything over 35V AC and 70V DC is considered low voltage ( same clasification as 240Vmains) the DC power supply rails of the device and possibly the speaker output may also require the same treatment.

    In truth in most states of Australia you havent been legaly able to build 240v powered projects in living memory... unless you have some sort of electrical licence.

    cheers

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  9. #8
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    you know, its interesting, I did my Electronic Trades in '97 and there was not a single thing on standards. I know things have come a long way since then (and the trade is now no longer a trade as far as I know...) but it seems a bit queer in hindsight.
    There are so many things using switch mode power supplies that its becoming harder and harder to test output voltages, let alone fix anything.(I have fried my share of Multimeters on switch mode stuff) Not so long ago I could fix most things with an OK multimeter and a soldering iron. Now, I am the first guy to say to people - chuck it, buy a new one.

    The trouble with low voltage is the inversly proportionally high current. The number of auto electricians I know that say that the big thick wires in cars are to stop arcing is ridiculous. Big thick wires 'cause if youre running a 200 watt amplifier at 12 volts then the current is at least 16 amps. This sort of current makes your wiring into a heating coil. Hence the big wiring. The bigger the coaxial cross section of the wire, the lower the resistance of the wire, hence the lower the affected voltage across the wire. And at 12 volts you cant afford to drop any voltage across your wiring.

    So low voltage stuff might be safer to work around, but the potential for combustion is probably higher. I have seen quite a few car stereo's cause a fire in the dash board.

    We need heavier standards in the application and installation of DC equipment.
    At the moment you can have your car stereo and 500watt amp installed "professionally" by a pimply kid just out of highschool, and when you ask if they know Ohms Law, they ask what channel its on...

    Still, it also makes it really difficult for startup businesses to get a foothold on a difficult market.
    I don't like the idea of running a 100w guitar head off a plug-pack. But it would be at least conceivable, I guess (yuck yuck yuck!!!)
    Cheers!
    Mongrel


    Some inspirational words:
    "Talent is cheaper than table salt. What separates the talented individual from the successful one is a lot of hard work." -Stephen King.
    Besides being a guitar player, I'm a big fan of the guitar. I love that damn instrument. -Steve Vai
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  10. #9
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    Please note that when I say above and any laws and standards say "low voltage" they mean the group that includes 240V mains. As In NOT "High Voltage" which is the real nasty stuff.

    12V and such is clasified as "Extra low Voltage"

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  11. #10
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    Quote Originally Posted by soundman View Post

    As for the standards
    The only ones that are realy enforcable are the electrical compliance standards, in particular AS3100.

    Soundman

    Not sure what you mean by not enforceable. All AS/NZ standards are enforceable, thats what they are for. Don't want to get too dramatic but a lawyer in a court of law will bury you based on those standards should something go wrong causing injury or property damage. As an electrician I have read several cases where exactly that has happened.

  12. #11
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    There are heaps of australian standards that are not enforcable.

    All the TV antenna and burglar alarm standards are are pretty well unenforcable and pretty well ignored for the most part. Because they are not referenced in legeslation.

    On the other hand most of our electrical standards are referenced in legeslation or chain referenced in standards that are referenced in legeslation.

    In fact I would go as far as to say the larger proportion of standards are only of any use at all because they are referenced as part of specifications, conditions of use of trademarks or contracts for specific works.....if they were not referenced they would be and ARE largely ignored.

    It may not be the ideal situation, but that is the way it is.

    If you can teel me of an applicable standard that is not an electrical one that applies to building an amplifier I would be interested to hear.
    BTW I don't count the electromagnetic compatability framework as a standard.

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  13. #12
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    Quote Originally Posted by soundman View Post
    If the item has an analog power supply and is a linear analog device that can not produce RF or switch heavy electrical such as a light dimmer or a switch mode power supply the C tick certification is relativly easy.
    You might be interested to pick up a recent past issue of Silicon Chip magazine. There has been some discussion of an audio amplifier's linear power supply that has been causing interference. You can't just assume that because a circuit is linear and analogue that it won't be a problem.

    Quote Originally Posted by soundman View Post
    BTW I don't count the electromagnetic compatability framework as a standard.
    Even if "referenced in legislation"? http://www.acma.gov.au/WEB/STANDARD..PC/pc=PC_1989

  14. #13
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    No the electromagnetic compatability framework is not a standard. It is a regulatory document but it is not a standard.

    Also if you read the page referenced in the link, the emc framwork is unenforcable in any way for the hobbist. They are responsible for spurious radiation as they have been in the past, but they are not bound by the framework.

    Before you comment on the provisions of the framework and its accompanying legeslation you would be wise to read it.

    Analogue devices are clasified much lower in the order of things than items such as switchmode supplies and highpower electronics such as light dimmers and motor controllers. The requirements, testing and proofs required for simple analogue items are many times easier to comply with.

    as for amplifiers creating spurious radiation, the liklihood of the powersupply causing radiation is many times lower than the amplifier output stage its self.
    Again read the pasage you have quoted from my post.

    No I have not regularly read any of the remaining hobbist electronic magazines for many years......the discussion in those magazines has always been no better than the discussion on internet forums without the pier review..

    I lost faith in these electronic magazines, when I submitted a simple diode battery charge sharing & isolation circuit for the circuit ideas column, and the esteemed editor ( reveered as a significan electronic brain) wrote back to me saying it could not possibly work as described. I wholey expected to be knocked back because it was not original, as it has been in just about every telephone exchange since the 50's, and can now be purchased as a wonder device in the 4WD and caravanning community. No discussion about the obvious limitations or drawbacks, just it could not possibly work....This is 1st year diode and battery theory, nothing clever.

    anyway.

    Please explain to me how a properly designed and fabricated simple analogue power supply (transformer, diode bridge and capacitors) with no faulty components can produce spurious radiation. apart from the expected 50 and 100Hz humm......

    On the other hand it is a lot harder to build a high power output stage that does not have the posibility of producing spurious radiation, particularly using FETs. I can detail first hand several cases.

    Then try and prosecute someone who is producing spurious radiation, I was involved in detecting and reporting two cases where a TV channel was being wiped out over most of a suburb........The RI's had a bugger of a time getting the purpetrators to desist, let alone making a prosecution.

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  15. #14
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    Anybody can build anything they like and plug it into the mains and there is no law to stop them doing so. The issues would start if you tried to sell your build. As a domestic electronics technician, there is no test I can sit to get any form of licence to do my job. The closest I came to that was a test at RMIT to get a union backed trade certificate which was only needed due to a pay dispute. Radiation is common from many appliances and if you want to find out who is causing it you need to write to the authorities then go on the waiting list, chances are the TVI will have stopped years before you get a result. As to radiation, all you need is a poor earth some power and an antenna. Switch modes can easilly create harmonics due to sharp cutting on and off of 100hz rippled DC. Worst ever I had was a standard light globe, just how it radiated TVI I have no idea but it did. So your simple answer is build your thing but if you want to make it for sale it has to be submitted to the regulators.

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