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Technics Tuner ST-G70l - How can I recieve am with out orginal AM loop jack?

Discussion in 'Hi Fi Systems & Separates' started by dupfold, Aug 24, 2009.

  1. dupfold

    dupfold Member

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    Hello

    I have a Technics ST-G70L and I would like to listen to AM radio, however I do not have the AM loop antenna that came with it.

    I purchase this today...

    AM/FM Radio Amplified Aerial : Radio Aerials : Maplin

    ..and while this gives excellent results with FM, I still have nothing with AM.

    I then found the manual for my tuner online...

    manuals - Folder Shared from Box.net - Free Online File Storage

    ..and that advises that I still need an AM loop to receive AM, regardless weather or not an external aerial is used.

    Problem is, the AM loop connect at the back of the tuner needs a two pin jack. I'm search for AM loops online, but they are seem to have the two prong connection, which the aerial I purchased today already has (and is already hooked up).

    Is there a universal AM loop with a two pin jack available I could purchase? Or even a parts place for VERY old Technics tuners? Or something else I can try?

    Help please.
    Last edited: Oct 20, 2009
  2. S Bibby

    S Bibby Member

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    Hi,
    I think you might be better off posting in the cables forum. Still don't know what this two pronged business is about - did you mean two binding posts? There are often two 300 Ohm posts for FM and one for AM.
    Last edited: Aug 27, 2009
  3. Crocodile

    Crocodile Well-Known Member

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    Looks like the G90 used the same aerial & may be available here as a spare part.
  4. Mark.Yudkin

    Mark.Yudkin Active Member

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    To receive AM with this combination FM/AM aerial you also need to connect the spade points on the aerial to the corresponding AM screws on the back of the tuner. This is in addition to the FM connection that is currently connected.
  5. BlueWizard

    BlueWizard Well-Known Member

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    Right, I'm with Mark on this. The AM/FM antenna implies separate outputs for AM and FM. You need to connect the FM to the FM, and the AM to the AM.

    For an AM antenna, all you really need is a length of solid wire; think of a car antenna.

    We can't comment on the two pin AM connector on the amp if we can't see it. Most have either spring clamp connections or screw connections. And in most cases only one of those connections does anything.

    I would say the first thing to do is find a way to connect the AM section of your existing antenna to the tuner. And again, we can't possible know every connector on every amp ever made. If you want us to comment on the AM connector, then we need a photo.

    I think there is a solution here, you are just not seeing it at the moment.

    Steve/bluewizard
    Last edited: Aug 27, 2009
  6. S Bibby

    S Bibby Member

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    I wanted to say this in an earlier post but from what I see of that Maplin aerial it is a coax connection. I think this means there is only one plug, and it is 75 Ohm?
  7. BlueWizard

    BlueWizard Well-Known Member

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    This is what I'm going by -

    "A stylish dedicated radio aerial with both AM and FM outputs... "

    Also, someone asks -

    "...2 spade points on the aerial lead, next to the coax cable..."

    That implies there are two connection points; 'Spade points', and 'Coaxial'.

    Now, I can't be sure, but for the moment, it seems a reasonable assumption.

    Though the AM loop antennas are pretty cheap. It is just a matter of resolving the type of connection on the Tuner.

    Steve/bluewizard
  8. S Bibby

    S Bibby Member

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    I don't use coaxial either but I suppose if this is an issue then a Balun (75 > 300) could be used. AM is usually a separate connection though isn't it? You also get poor reception from a single lead in most parts of the UK.
  9. dupfold

    dupfold Member

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    Heres a pic to make things clear.

    [​IMG]

    As you can see I need a loop with a two pin connection to fit. Without the loop I cannot get a signal, with or without an external (ext) connected.

    Does anyone know where I can get purchase a suitable loop please?
  10. Crocodile

    Crocodile Well-Known Member

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    Did I post invisible text in post #3?
  11. dupfold

    dupfold Member

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    Thanks but 'No longer available'
  12. BlueWizard

    BlueWizard Well-Known Member

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    If you follow the link Crocodile provided, it lead to this -

    buyspares.co.uk - Panasonic Loop Antenna for Technics STG90 - Spares, Spare Parts & Accessories

    Which is a direct replacement for the AM Loop antenna for a Panasonic/Technics model STG90L.

    Sadly though, it seem to be 'no longer available'.

    I really can't tell from your photo what the connection is like. On most is it two mini spring compression terminals.

    Here is a long list of common AM Loop antennas, though I suspect most use a common two wire connection, as described above.

    [Sorry, I forgot to add the link.]

    http://www.buyspares.co.uk/cgi-bin/search.pl?query=AM Loop antenna&search.x=0&search.y=0&search=s

    Notice the models listed here are specifically Technics Loop Antennas -

    buyspares.co.uk

    But the only one with a photo doesn't seem to use a plug connection.

    Again, I can't see the loop connection clearly enough to under stand how it works, but logically it would be a 2-wire connection, though they may be some type of pins or plugs.

    Any AM loop will work, you just have to work out how to jury rig the connections. It the connections are tight enough, you can just push the wires into the holes.

    Did you say you had the Owner's Manual for this amp? If so, maybe you can cut and paste from the owner's manual a close up drawing of the AM Loop plug.

    I'm stuck with the fact that I can't solve a problem that I can't see. Though I have no doubt that the problem can be solved easily, you just need to use a little ingenuity.

    Next, what have you done about the EXT AM antenna, how much wire did you use, what kind of wire, how long, how did you place it?

    I suspect there is some way to adapt the AM/FM antenna you have to work with your amp, but again, I'm not there, I can't see it. It gets down to the level of inventiveness and ingenuity you are willing to apply to solve the problem, which I am convince can certainly be solved.

    Steve/bluewizard
    Last edited: Oct 20, 2009
  13. dupfold

    dupfold Member

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    http://i907.photobucket.com/albums/ac279/jackhulk/201020091711.jpg
    http://i907.photobucket.com/albums/ac279/jackhulk/201020091712.jpg
    http://i907.photobucket.com/albums/ac279/jackhulk/Technics1.png
    http://i907.photobucket.com/albums/ac279/jackhulk/Technics2.png

    I have recently purchased the Terk Advantage (imported from the US) which is one of the best in Ext AM in the market. No problems connecting to the amp but this antenna (and any other) can be taken out of the equation at the moment, as without the loop, the EXT antenna makes no difference what so ever.

    I hope you can see the pics a little better now? I need an AM loop with a tiny plug connector.
    Last edited: Oct 20, 2009
  14. S Bibby

    S Bibby Member

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    Yes, I can see that it looks like a proprietery cable - my AM Antenna is usually attached to the Tuner by plastic clip. The signal connections are 300 ohm to a binding post.

    I haven't always used Loops, and I still think you have another choice in using a regular aerial, perhaps to a curtain rail? But I would honestly recommend you post in the cables forum to get more replies.
    Last edited: Oct 20, 2009
  15. dupfold

    dupfold Member

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    Ok I will try post in the cable section, but don't wanna p off the mod's with double post. Perhaps a mod can move this thread please?

    No idea what 300ohm, binding post etc means/relates too (layman terms please :) This is really not my field, all I know is that most, if not all the loop aerials I come across only have two loose wires, but I need to find one with a suitable tiny plug connector.

    Surely someone must of come across this problem before, but I've Googled this to death and getting no where first. I've contacted specialist parts suppliers but to no avail. I think I should be able to use a standard loop but I need the tiny plug adaptor, but what is the correct name for that particular plug?
  16. BlueWizard

    BlueWizard Well-Known Member

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    I would suggest you us any standard loop antenna, and go to Radio Shack/Tandy or Maplins or similar, and see if you can find a couple of sockets that will fit those pins. Solder or crimp the sockets to the ends of the wires on the standard loop antenna. Then push the sockets onto the pins.

    I'm not talking about a connector here, just two pin sockets that fit.

    Though they may have a connector, that while not an exact match, will still fit.

    That is about the best I can offer.

    Steve/bluewizard
  17. Roger Thornhill

    Roger Thornhill Member

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    See page 5 of the instruction Book you provided a link to. The page titled Antenna Connections.

    If you have to use a Loop Antenna then you will have to find the propietry Technics one, which will be extremely difficult now.

    So, the 'hand screwable' binding post, next to the socket for the loop antenna, labelled ''EXT'' should be used.

    You don't have to rig up something like what is mentioned in the instructions, but a reasonably long length of wire connected to this binding post and 'trailed' as high as possible should work well enough. You may have to 'experiment' with its orientation for best results.
  18. BlueWizard

    BlueWizard Well-Known Member

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    No, you simply have to have the ingenuity and resourcefulness to connect two wires to two pins.

    Certainly the external antenna will work, though if you look at the owner's manual, you will see it recommends a horizontal wire of 5 meter to 12 meters. That is probably not completely true. The AM antenna on a typical car is far from that length and they seem to work OK.

    Still to use a loop antenna you just need to find a way to connect two wires to two pins, and that simply requires a little resourcefulness.

    Steve/bluewizard
  19. Roger Thornhill

    Roger Thornhill Member

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    Do tell how you would perform this then, easier than just connecting to the EXT post.

    Aerials are designed to specific lengths depending what 'wavelength' of signal to be received. The aerials on cars will be divisions of the wavelengths of the signals to be received and calculated very precicely.

    However a simple lead connected to the EXT post will, i am certain provide the OP with excellent results, much easier than fiddling around trying to connect to the pins on the propietry socket.
  20. BlueWizard

    BlueWizard Well-Known Member

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    Well, we are drifting off topic to some extent.

    I would suggest that if you have a AM antenna source, either the antenna the original poster bought or a generic loop antenna, you connect one end of it to the EXT antenna connector. Yes, just one end. Though do try each end, one might work better than the other.

    As to antennas, transmission antennas are critical, receiver antennas are general. Transmitters transmit on one specific frequency. Their antenna must be absolutely precise. However, receiving antennas are general, they must receive across a broad band of frequencies. So, their length must be within a certain range, but it is not precise.

    Again, the solution gets down to resourcefulness. If the amp and antenna were at my house, the problem would solved. I have enough misc parts in my parts bin that I would have found something to fit.

    It looks like the pins might be on 1/10 inch centers, which means I've surely got parts from circuit boards that would fit. If they wouldn't fit, I would take a long connector, and cut it down into two individual connectors.

    So, while I'm not discounting the EXT antenna solution, I'm saying the Loop antenna solution is simply a matter of being innovative enough to figure out how to connect two wires to two pins.

    A trip to the hardware store or to the local electronics store might give you the solution you need.

    Steve/bluewizard
  21. Crocodile

    Crocodile Well-Known Member

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    Do you have access to an old PC case? The connectors for the front panel LEDs (like these) may be of the correct size. If you can't get hold of some to try, PM your address & I'll send you one.
  22. dupfold

    dupfold Member

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    Thats brill! Thanks Crocodile, that worked nicely!

    Thanks all, problem solved.
  23. martineaux

    martineaux Member

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    The connector on the back panel looks much like the one on my Philips tuner(on which Philips has "no information"). Here in the US, most cordless phones use connectors much like this, so I'm off to the store to look for a battery with a 9/32" (0.281") x 5/32"(0.156") connector with 2 pins set at a pitch of 3/32(.0094").

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