Circuit Problem

Discussion in 'The Projects Forum' started by crivoli, May 6, 2006.

  1. crivoli

    Thread Starter Member

    May 4, 2006
    26
    0
    Please help me!!!

    I have built the intercom circuit found at (
    http://www.uoguelph.ca/~antoon/circ/intercom.html ), but it does not
    work.

    Are the audio transformers necessary with the 8ohm speakers? I cannot get any noise on the line at all. No sounds comes out from anywhere.

    Any ideas?

    Thanks
    -Chad
     
  2. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    4,018
    1,772
    Do you have the test equipment to make some tests?

    Have you measured anything? If so post what you measured ... and where you measured it.
     
  3. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    4,018
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    There is nothing wrong with the design by Jan Hamer. You need to check and see what you have done improperly.
     
  4. richbrune

    Senior Member

    Oct 28, 2005
    106
    0
    8 ohms = bc558b Kaboom
     
  5. brockrwood

    Member

    Oct 23, 2016
    47
    6
    You definitely need the transformers if you want to use 8 ohm speakers. One transformer for each speaker. The 8 ohms impedance is too low for the amplifier circuit. You need a transformer that presents a higher impedance to the amplifier (primary) with a lower impedance on the secondary, facing the speaker. Do a google search for "8 ohms audio transformer".
     
  6. dl324

    AAC Fanatic!

    Mar 30, 2015
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    You're trying to answer a post that was 10 years old when you joined. Necroposting to a 12 year old thread must be a record.
     
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  7. brockrwood

    Member

    Oct 23, 2016
    47
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    I see your point. In my defense, however, other people viewing the thread may have a similar problem right now, at the current time. MY reply to the original post was intended to help any people on AAC who view the thread and have a similar problem.
     
  8. SamR

    Member

    Mar 19, 2019
    189
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    LOL... My word of the day, but I doubt I will get to use it in a sentence...
     
    brockrwood likes this.
  9. sghioto

    Well-Known Member

    Dec 31, 2017
    1,021
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    brockrwood I'm just curious how you found that post. I believe it was on page 1569 of 1575.
    Did you start from the last page and start working backwards?:)
    SG
     
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  10. brockrwood

    Member

    Oct 23, 2016
    47
    6
    You guys are being unnecessarily mean to me. I stand by my convictions! I do right by the members of AAC! I help, even if the problem is 13 years old! ;-) Maybe he hasn't figured it out yet and the circuit, on a breadboard, is still floating around at the bottom of his "circuit projects in progress" box? I have such a box. There are half-built circuits in there from 5 or 6 years ago. Oops. Maybe I should not admit that... ;-)

    How I found the post: I was doing my OWN search on the right values to use for an audio output transformer for a similar circuit. Badda-boom, badda-bing, this old post popped up.
     
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  11. Yaakov

    Well-Known Member

    Jan 27, 2019
    1,147
    548
    They are only mean to people they like...

    ...and people they don't like.

    But I am pretty sure they like you.
     
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  12. brockrwood

    Member

    Oct 23, 2016
    47
    6
    Yes, I know. That was the reason for my winky faces. ;-). And I appreciate the experts on AAC putting up with my sometimes uninformed hobbyist level questions. The willingness of the AAC members to give so freely of their time and expertise is awesome!
     
  13. sghioto

    Well-Known Member

    Dec 31, 2017
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    The "winky faces" didn't come through on my computer. I got this ;-) not ;)
    I didn't think you were serious but wasn't 100% sure.
    SG
     
  14. brockrwood

    Member

    Oct 23, 2016
    47
    6
    :D:D:D:D:D:D:D:D
    To everyone who posted replies to my replies: ;););):):D:D
     
  15. MrAl

    AAC Fanatic!

    Jun 17, 2014
    5,723
    1,211
    Hi,

    What is amazing to me is that we actually see threads this old. It doesnt seem that long ago but wow it was. Let's see, 2019 minus 2006, that's something like 12 to 13 years old. However, most information dies very slowly over decades and this thread is still relevant.
    It's hard to believe that i posted some in other forums around 1998. That's more than 20 years ago! Geeze.
     
  16. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    5,448
    6,028
    Time passes on. In the 80's I was running a dial-up technical forum BBS on a Convergent Technologies "Miniframe" (later a MegaFrame) from my house. The questions were pretty much the same at the basic circuit level.
     
  17. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    7,547
    2,140
    FidoNet and Slimer !!!

    ak
     
  18. killivolt

    Distinguished Member

    Jan 10, 2010
    597
    866
    Either I'm in the wrong location? or I can't see the original circuit because the page doesn't exist anymore.

    kv
     
  19. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Right location, but late to the party. That page is long gone, but reproduced here:

    http://www.tonyvanroon.com/oldwebsite/circ/intercom.html

    ak
     
    Last edited: Apr 6, 2019
    brockrwood and killivolt like this.
  20. brockrwood

    Member

    Oct 23, 2016
    47
    6
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