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3.5mm jack plug/socket standards?

Discussion in 'Electronic Design' started by Terry Pinnell, Jan 31, 2004.

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  1. I've posted separately about distortion problems with a newly-built
    stereo amplifier. Isolating that was hindered because I was also
    getting some noise due to loose plug fittings.

    Input and output is via 3.5mm stereo jack plugs and sockets. I find
    that the fitting is very critical; the slightest movement outward of
    the plug loses one or both channels.

    Looking closely at four types of plug I have on hand, I note some
    differences in dimensions, particularly in the lengths of the ground
    and middle sections.

    Shouldn't all 3.5 mm stereo plugs reliably fit all 3.5 mm stereo
    sockets? If so, why are the dimensions therefore not a more
    tightly-met standard?
  2. Genome

    Genome Guest

    The crap you buy from Maplin and such like is exactly that. Cheap, nasty and
    probably hand made.

    When Sony et al design product they use buying power to get what they
    specify so it's all nice and snug.

    3.5mm isn't exactly proffesional stuff so don't expect great things. Use
    phono's instead. Not necessarily better made but the fit will be snugger and
    you can always sprange it a bit for a tight fit.

  3. Just had similar problem using 3.5 phono and socket for 9V DC power
    feed into a project. With the socket/plug in series; the rail voltages
    were 8V/0V. When hard wired directly thereby bypassing the
    plug/socket; the voltage was back up to 9V again. No amount of
    twiddling with the fit and cleaning the surfaces would get rid of that
    residual resistance in the connection so I've hard wired the power in
    permanently. Problem sorted.
  4. Leon Heller

    Leon Heller Guest

    Use good quality plugs and sockets. Rendar's are very good, if expensive.

  5. Thanks both. But I'd still be interested in comments about the
  6. N. Thornton

    N. Thornton Guest

    3.5mm jack is what you get on bottom end equipment, typically
    connected to whats basically fuse wire. Its not pro stuff. Thats its
    place in life. There are always poor quality products about, if you
    want a relatively good one, buy one thats relatively good.
    like what?

    Regards, NT
  7. I wouldn't describe my 400 UKP (700 USD) Pocket PC as 'bottom end
    equipment'. And I imagine there's a *lot* of expensive equipment
    sporting 3.5mm jack sockets, largely because of compactness
    Like some basic facts, including what tolerances are allowed.
  8. I'm sure there's not more than $10 worth of audio related components in
    your Pocket PC, so it COULD be described as bottom end audio gear.
    Yes and no. When you get into the high end, sometimes compactness is
    sacrificed for reliability. XLRs and 1/4" phone jacks start showing up,
    and RCA jacks and 1/8" phone jacks start to disappear.
  9. I read in that Terry Pinnell <[email protected]
    I posted this but it seems to have disappeared:

    I read in alt.binaries.schematics.electronic that Terry Pinnell
    >) about '3.5mm jack plug/socket standards? -
    JPscompared.jpg', on Sat, 31 Jan 2004:
    Yes, they should.
    There IS a standard, IEC 60603-11, whose introduction was very long
    delayed by a spat between Japanese interests (with a world-wide market)
    and US interests (with no market to speak of). It didn't help that two
    British manufacturers also introduced totally incompatible versions.

    All plugs and jacks that conform to the standard should work together.
  10. Tim Shoppa

    Tim Shoppa Guest

    The 3.5mm plug has always seemed totally inappropriate for power
    connections. It is nearly guaranteed to short out when you insert
    or remove it. While most wall-warts will withstand this abuse
    without a hitch because of their high internal resistance, it just
    seems wrong to me.
    OTOH there are many good polarized connectors out there which are quite
    suitable for power. The only problem is lack of agreement as to which
    polarization convention for those coaxial plugs :-(, but we have workarounds

  11. Thanks, John.
  12. I read in that Tim Shoppa <[email protected]
    That, too, is now standardized, with + in the middle, but go talk to a
    brick wall.
  13. Agreed. Just another expedient in my case...
  14. I wouldn't trust that convention - checking first rules.
  15. Depends on your posisiton in the value chain does it not?

    It may well be that you paid GBP 400 for about GBP 75 worth of product -
    thats delivered on the dockside in the UK btw. Off-factory, in China, it
    will be less than that!

    Remember, "the price" is merely whatever one can take the customer for
    without him taking undue offense ..... or why *else* do you think that f.ex.
    the now-oldish T68i cellfone retailing at better than GBP 200 only about a
    year ago is still available in multitudes at only GBP 20 now - it is not
    because someone suddently decided to loose money on that sale!
    Sony f.ex. buys millions of connectors; they can demand good specs and
    therefore their stuff performs.
    Whatever you like, I assume - I do not think there *exists* a meaningful
    standard for 3.5 mm jacks etc.
  16. N. Thornton

    N. Thornton Guest

    Compactness encourages compromises. As an audio connector 3.5mm is
    bottom end, but compactness is sometimes more important. With
    computers, cost cutting is harsh too: if they can use a 3.5 and it
    works, they will. Even if your PC were top end, that doesnt preclude
    it from using bottom end connectors.

    John Woodgate might correct me on this if I'm wrong, but as I
    understand it, what is allowed is determined by case law, and
    primarily revolves around what works and doesnt injure people. IEC
    specs are good things to use, but I would assume that connectors not
    meeting them are allowed. And equally connectors that do meet them are
    also not allowed in many apps.

    Regards, NT
  17. I read in that N. Thornton <>
    'Allowed' is a big word. In practice, what is allowed is what no-one
    complains about.
    We often have to point out to zealous standardizers that the IEC does
    not have a gaol, but does have a goal. It works by persuasion.

    In the case in point, though, someone has complained, and he is not
    alone. It's simply daft for people to make connectors that don't meet
    the IEC standard.
    I don't know about that. What have you in mind?
  18. N. Thornton

    N. Thornton Guest

    Unfortunately daftness doesnt stop quite a few people.

    A 3.5mm jack can meet the highest of standards, it still wont be
    allowed if its carrying mains power. Just as one example of why
    meeting IEC specs doesnt guarantee allowabililty. A more likely
    example might be where the connector would usually be suitable, but
    wouldnt for some less obvious reason, eg... trying to think... I know,
    if 3.5s were used on stage audio kit a judge might well uphold the
    claim that they werent suitable for job since they dont survive the
    normal expected level of abuse in that app.

    Regards, NT
  19. I read in that N. Thornton <>
    Doesn't meet IEC 61984 on connector safety.
    Doesn't meet IEC 60268-12.

    You happen to have chosen two examples where IEC standards exist that
    would be violated. But of course there are cases where a given connector
    should not be allowed, even if there is no standard that specifically
    disallows it. There was one example, I recall. Audio amplifier power
    consumption is measure at 1/8 of rated output power. This amplifier took
    1.8 A, so it was fitted with an appliance connector rated at 2 A. But of
    course at full output power it drew far more than 2 A. The certification
    body was disturbed to find that IEC 60065 (before the days of ENs)
    didn't disallow this. The BSI committee suggested that an appeal to the
    common sense of the designers might work, and it did.
  20. expensive.

    Do you have a US source for those? I've been searching for decent quality
    3.5mm stereo jacks for a product I manufacture, to no avail. The 3.5mm
    connectors I've been able to find are uniformly crap.

    I see that Rendar seems to have been acquired by Schurter; but none of the
    Schurter distributors I can find (Avnet, Digikey, Mouser, Future, ...) seem
    to carry their audio connector line.

    I have emailed Schurter, but any leads anyone could give me would be much
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