Bananas

I've eventually got round to buying some banana plugs for my AV unit, however I don't know how to convert the terminals on the back of the unit to facilitate them.
Could some kind soul shed some light on the subject.

Comments

  • [Deleted User][Deleted User] Posts: 10,327
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    What sort of terminals are they?
  • [Deleted User][Deleted User] Posts: 1,102
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    If it's like most AV receivers there are little plastic bungs in the hole where the Banana plug fits, just gently prise them out with a small screwdriver :)
  • webbiewebbie Posts: 1,614
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    Yes, more eu meddling! Banana sockets were sort of banned because there is potential for someone to touch the terminals and get a shock but the amp and speakers would have to be very powerful for the voltage to reach that high. Nevertheless, the eu banned them so they are now covered up or hidden or have bungs in them on AV equipment.
  • [Deleted User][Deleted User] Posts: 986
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    webbie wrote: »
    Yes, more eu meddling! Banana sockets were sort of banned because there is potential for someone to touch the terminals and get a shock.
    I thought they were banned for being too straight?
  • GaseousClayGaseousClay Posts: 4,313
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    paulr2006 wrote: »
    If it's like most AV receivers there are little plastic bungs in the hole where the Banana plug fits, just gently prise them out with a small screwdriver :)

    That sounds familiar I'll look into that. Thanks for the replies.

    Edit: That was the jobbie. Tricky little critters aren't they. :p

    Thanks Paulr2006 ;)
  • rjb101rjb101 Posts: 2,689
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    I thought they were banned for being too straight?

    Na, Cucumbers for being to bent. :) You'll never plug a bent cucumber into any AV Equipment.

    Thank god for the E.U. :o
  • pocatellopocatello Posts: 8,813
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    mumble...
    So how many europeans died to banana plugs before they decided it was worth the effort of legislating against.
  • OrbitalzoneOrbitalzone Posts: 12,627
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    I thought banana plugs were banned because they can easily be pluggeg into a 2 pin mains socket in Europe? (no shutters on those sockets) - to protect dopey people from plugging their banana plugged speakers directly into the mains?

    I might be wrong though!

    I imagine manufactures cover the speaker terminals with a bung to meet some EU directive.... it's not to stop people getting a shock from the speaker terminal (that would have to be quite an amp and quite a stupid person to get shocked)
  • Pugwash69Pugwash69 Posts: 3,787
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    If you have round screw-down posts they will probably have the bung in the centre for bananas. If you have sprung clips you're out of luck.
  • grahamlthompsongrahamlthompson Posts: 18,486
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    I thought banana plugs were banned because they can easily be pluggeg into a 2 pin mains socket in Europe? (no shutters on those sockets) - to protect dopey people from plugging their banana plugged speakers directly into the mains?

    I might be wrong though!

    I imagine manufactures cover the speaker terminals with a bung to meet some EU directive.... it's not to stop people getting a shock from the speaker terminal (that would have to be quite an amp and quite a stupid person to get shocked)

    Your explanation sounds much more likely. Simplistic approach but to deliver 500W RMS from a pure sine wave into a 8 ohm load requires 7.9A RMS. To drive this the amp is only outputting 63V and that's a dirty great amp.

    Take my 130W/channel Denon that figure falls to 8V (less than a car batttery).
  • webbiewebbie Posts: 1,614
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    63V is above the SELV (safety extra low voltage) limit so if its possible that the amp can put out this voltage then the outputs must be fingerproof or you cant CE mark your product and sell it in europe. This is part of the eus low voltage directive. You are right about the sockets in that they must not be of the same type as used for the mains but a 4mm banana would be OK I'd have thought, at least in the UK.
  • webbiewebbie Posts: 1,614
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    The SELV limit is defined as 30V rms and 42.4V peak or 60V d.c. So if the amp can exceed these voltages, then the output needs protection against fingers.
  • grahamlthompsongrahamlthompson Posts: 18,486
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    What about the speaker terminals do they need to be Kite marked ?

    My Kef ones are solid metal with thumbscrews (ie no insulation at all) and they are rated at 130W RMS
  • webbiewebbie Posts: 1,614
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    My speaker terminals are the same.
    I don't know the rules for them - perhaps as they don't generate the voltages they have different rules? EU rules don't have to make sense!
  • OrbitalzoneOrbitalzone Posts: 12,627
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    webbie wrote: »
    My speaker terminals are the same.
    I don't know the rules for them - perhaps as they don't generate the voltages they have different rules? EU rules don't have to make sense!


    That is certainly true! :D
  • webbiewebbie Posts: 1,614
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    I've found out more - for audio amplifiers the hazardous voltage limit is around 71V rms as the output isn't normally at mains frequency so it looks like the reason that 4mm plugs are "discouraged" is that they do fit nicely into european schuko sockets.
    Why the eu has to treat us like idiots is the subject of my next posting....
  • grahamlthompsongrahamlthompson Posts: 18,486
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    webbie wrote: »
    My speaker terminals are the same.
    I don't know the rules for them - perhaps as they don't generate the voltages they have different rules? EU rules don't have to make sense!

    Actually speakers do generate voltages, as the cones overshoot the magnets moving within the coils generate a back emf and current in the speaker connections. The better the amp can absorb this current the less overshoot and the purer the sound.
  • webbiewebbie Posts: 1,614
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    ...and they also act as microphones and output a low voltage but I think I'll struggle to get 70V out of them! The relevant eu standard is EN60065 which gives us all the safety rules but is far too boring to mention here.
  • grahamlthompsongrahamlthompson Posts: 18,486
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    webbie wrote: »
    ...and they also act as microphones and output a low voltage but I think I'll struggle to get 70V out of them! The relevant eu standard is EN60065 which gives us all the safety rules but is far too boring to mention here.

    Actually the voltage is likely much higher than you think but of very short duration. The output voltage is directly proportional to the speed of the movement. The faster the magnet moves in relation to the coil the higher the transient voltage generated. Not that it would hurt a fly because the amount of energy is so small the instant you pull a current off it it will collapse. Static electricity can generate thousands of volts, it won't kill you because a tiny current discharges it. Current kills not voltage. No current no problem. A car struck by lightning is perfectly safe to the occupants as every point in the car is the same voltage (Farady Cage Effect). Birds quite happily sit on 33000volt overhead line conductors
  • OrbitalzoneOrbitalzone Posts: 12,627
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    Gosh does that mean i win the £5 prize for being right for once?

    :D


    cue Monty Burns voice: [mb]Excellent[/mb]
  • cnbcwatchercnbcwatcher Posts: 56,681
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    rjb101 wrote: »
    Na, Cucumbers for being to bent. :) You'll never plug a bent cucumber into any AV Equipment.

    Thank god for the E.U. :o

    :D:D:D Wonder what it difference it makes if cucumbers are bent or straight?
  • webbiewebbie Posts: 1,614
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    Yes, you win the £5 prize. Apply for it by writing your name and address on the back of a £10 note and send it to me....
  • OrbitalzoneOrbitalzone Posts: 12,627
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    webbie wrote: »
    Yes, you win the £5 prize. Apply for it by writing your name and address on the back of a £10 note and send it to me....


    I've only got a £20 will that do?
  • Nigel GoodwinNigel Goodwin Posts: 58,272
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    Take my 130W/channel Denon that figure falls to 8V (less than a car batttery).

    I would suggest you check your maths again :D

    130W in 8 ohms is 32V RMS, or 90V p-p.
  • GetFrodoGetFrodo Posts: 1,805
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    webbie wrote: »
    perhaps as they don't generate the voltages they have different rules? EU rules don't have to make sense!

    It doesn't matter where the voltage is 'generated', the voltage between the red and black outputs of the amplifier will be the same* as the terminals of the speaker - that's why we all buy chunky fat speaker cables to ensure just that.

    *well pretty damn close.
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