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TDA7000 receiver project

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by zachtheterrible, Oct 7, 2004.

  1. zachtheterrible

    zachtheterrible Active Member

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    Hi everybody :lol: , I just got all of the parts to make my TDA7000 receiver in the mail yesterday, so now im going to build it, and will probably be needing some help every once in a while (like right now).

    There is going to be a jack to put earphones in. The jack is the kind that you would normally use to plug speakers into the back of your computer, or the kind of jack on a regular portable cd player, I think that it is 1/8 in. Neway, I think that I’m missing something. I took the plug that leads into my speakers from my computer, and was touching it. When I touch the top, the right speaker hums, when I touch the middle, the left speaker hums, when I touch the bottom, nothing happens (i think that must be the common or something). When I put the plug into the jack that I got, I tried touching the prongs . . . The thing is, I can only get one speaker to hum, so it would seem that when I make my circuit, only one side of my earphones is going to make sound. Am I connecting it the wrong way or something?

    Here is a picture of the jack. I think that it is 1/8 in., but I’m not sure.
     

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  2. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    That's because you have a mono socket, not a stereo one. For both channels to work you need a stereo socket, and short the tip and ring together to make both channels work.
     
  3. zachtheterrible

    zachtheterrible Active Member

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    Thats wut i figured :cry:
     
  4. dave

    Dave New Member

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  5. zachtheterrible

    zachtheterrible Active Member

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    Found me a stereo jack :lol:

    How should I solder my tda7000? Is it very heat sensitive, or would I just solder it like I would any other component?
     
  6. chemelec

    chemelec Well-Known Member

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    Even though it is high freqiency and it will add a bit of capacitance, I would suggest a Socket.

    By the way Zack, I bought 2 of those chips to play with. As soon as I get some free time.
     
  7. John Sorensen

    John Sorensen New Member

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    The best thing to do with hard to get or expensive parts is to use a socket. Also, when you build the thing and it doens't work, it's easier to pull out the chip and replace it with a different one to see if the chip is bad*.

    j.

    *The down side of this is that if it was the board that smoked the chip, then putting another chip in it means now you got two smoked chips.
     
  8. -=GST=- Nemisis (cs/cz)

    -=GST=- Nemisis (cs/cz) New Member

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    :shock: does using a socket affect the curcuit??????? :shock:
     
  9. John Sorensen

    John Sorensen New Member

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    Of course, but not usually to have any effect. Most of the circuits I design are digital or simple analog, and the only real problem with sockets is mechanical failure. I suspect, like Chemelec suggested, that the TDA7000 might be more sensitive to stray capacitances/inductances, but I'm no RF whiz. I'd socket it anyway, because they're so hard to get and more expensive than the parts I consider "disposable".

    IMHO.

    j.
     
  10. chemelec

    chemelec Well-Known Member

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    Sockets Add Capacitance. This will lower the Frequency of the coil by a LITTLE BIT. Not Really a problem.

    I didn't find the Expensive. I think I only paid a couple of dollars each. Or I believe that is what my supplier said they would be. Haven't seen the bill yet.

    Gary
     
  11. -=GST=- Nemisis (cs/cz)

    -=GST=- Nemisis (cs/cz) New Member

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    lol i can get sockets for like 5p each :p
     
  12. zachtheterrible

    zachtheterrible Active Member

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    I think that i will socket it, good idea :D . i will probably build multiple receivers too
     
  13. imgemini

    imgemini New Member

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    hi

    can i have the cricuit plesae of ur circuit with parts list :oops:
     
  14. zachtheterrible

    zachtheterrible Active Member

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  15. zachtheterrible

    zachtheterrible Active Member

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    I tried asking harry about how to make the antenna, but havent got a reply 2 weeks, so ill ask here. I was told to make a diple aerial antenna, but have no idea how to go about doing this. I added the circuit that im building. Ive searched the internet dry and cant come up with anything that would really help me. If someone could point me in the right direction or tell me how to do it, it would be greatly appreciated.

    Also, ive lately been trying to figure out impedance matching. i think i basically get the main idea, but would like to be able to put it to use. Could someone point me to a good website?

    And would it be safe to suply this circuit with 9 volts? I like using 9 volt batteries :lol:

    Thanx :lol:
     

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  16. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Zach,
    He says (I couldn't find the datasheet) that the TDA7000 works with a supply voltage from 2.0V (worn-out two alkaline cells), to 10V which is a brand new 9V alkaline battery.
    Have you ever seen the small size of the cells inside a 9V battery? They surely won't last long. Compare the size (and spec's) of those tiny cells with AAA or AA cells. Two AA cells aren't much bigger than a 9V battery but will last at least 6 times longer, and are cheaper. Your choice.

    I don't like 9V batteries anymore, I'm designing thingys for 3V now.
    Have you seen this one?:
    http://www.electronics-lab.com/projects/science/018/index.html
     
  17. zachtheterrible

    zachtheterrible Active Member

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    Never really thought about 3 volt being beter than 9 volt, but that does make sense :lol:

    as for the antenna, i really need that info . . . . please??
     
  18. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Have you tried googling for 'dipole aerial design', there's loads of hits!.

    But a dipole is just two rods, you can easily make one from a piece of twin speaker wire - get hold of the two conductors, one in each hand, and pull them apart until your hands are fully stretched out sideways. This gives a dipole about the correct length for VHF radio - the other end of the wire connects to the two connections on the radio.

    If you want to calculate the length of the two rods, pick a frequency in the middle of the FM band, or a specific frequency you want to receive, and make each rod a quarter wavelength long.
     
  19. zachtheterrible

    zachtheterrible Active Member

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    Thanx nigel, thats exactly what i was lookin 4 :lol:

    i did try googling it, but all i could find was dipole aerials that were meant for being on the top of the roof and stuff, nothing simple
     
  20. zachtheterrible

    zachtheterrible Active Member

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    oh yeah, and is it possible 2 make the antenna smaller by using magnet wire or somethin like that? (the smaller the better :lol: )
     
  21. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    A dipole is the reference value for all aerials, you can make it shorter, but it won't work as well as one the correct length, so iy will have a negative gain value. A yagi is just a dipole with extra elements added (reflector and directors), it gives gain by making the aerial directional, and thus have a positive gain value.

    If you want the best performance make the aerial the correct length, if not, shorten it to where you want, but be aware that performance will fall accordingly.
     

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