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Please help with Kinetic Audio Amp

Discussion in 'Audio' started by skylar coy, Apr 29, 2017.

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  1. skylar coy

    skylar coy

    16
    0
    Apr 29, 2017
    This amp was built in the 70's and I need to replace the output transformer. Here is a schematic of the Amp. My issue is that I dont think the transformer is hooked up correctly now! Red is 16 ohm, Grey is 8 ohm, black is 4 ohm, brn is common. 8 ohm doesnt seem to be hooked up to anything. Just confused. Tell me what is wrong or if its just fine.

    Amp pics: https://ibb.co/kU6NBQ
    https://ibb.co/iP6NBQ
    https://ibb.co/iKhJkk

    Schematic: https://ibb.co/fWFXBQ

    On the schematic is shows the 4 ohm and 8 ohm wires and two more un labeled with a little triangle in them then going to that like with the 2 black triangles on them. What are the triangles and what is the line?
     
  2. davenn

    davenn Moderator

    13,502
    1,830
    Sep 5, 2009
    it would have been nice if you have rotated it correctly
    it would have also been REALLY NICE if I was able to download it rotate it and upload into this thread
    where people trying to help you have easier access to it

    PLEASE sort it out

    doesn't make much sense .... I see 4, 8, 16 on the output for the speaker connections
    but I don't see black triangles there
     
  3. skylar coy

    skylar coy

    16
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    Apr 29, 2017
    Here is it :) basically my question why is the 8 ohm wire all by itself not connected to anything, why is com and 4 ohm connected to the output jack, and why is 16 ohm where it is in the pictures i put.
    https://ibb.co/cUwprQ
    it wont let me upload it for some reason
    [​IMG]
     
  4. davenn

    davenn Moderator

    13,502
    1,830
    Sep 5, 2009
    OK I screen dumped and cropped the image from the your image site
    not being able to download the image is a pain

    so you are referring to the output I have circled in red ?

    upload_2017-4-30_8-7-29.png
     
  5. skylar coy

    skylar coy

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    Apr 29, 2017
    yes. I am quite sorry about that I have no idea what is wrong. But here my worries. The 8 ohm(grey) goes to nothing really, the red wire(16ohm) goes off away from the speaker jack. The only wires actually going to the jack's are com and 4ohm. The speaker jacks however are labeled 16 and 8 ohm.

    Grey wire: [​IMG]
    Red wire: [​IMG]
     
  6. davenn

    davenn Moderator

    13,502
    1,830
    Sep 5, 2009
    OK

    incorrect

    the 4 Ω output goes to the lower connector
    if you follow the wiring diagram, you will see that the 8 Ω output ALSO goes through the 4 Ω socket connector,
    it gets shorted out when the 4 Ω socket is in use (that is, when a speaker plug is plugged into the 4 Ω socket)

    the 16 Ω output doesn't go to the same style of socket, the schematic indicates that it has a different termination .... maybe a screw terminal


    Dave
     
  7. skylar coy

    skylar coy

    16
    0
    Apr 29, 2017
    So let me get this all straight. When i plug into the 16 ohm jack i have 16 ohms, when I plug into the 8 ohm jack I have 8 ohms. Which one also acts as the 4 ohm then? there is only two jacks
     
  8. skylar coy

    skylar coy

    16
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    Apr 29, 2017
    Oh i understand! so to get my jacks to truly be 16 and 8 ohm i need to replace the 4 ohm wire with the 16 ohm wire
     
  9. davenn

    davenn Moderator

    13,502
    1,830
    Sep 5, 2009
    the 4 Ω socket ..... are they not labelled on the back of the amp ?

    the schematic shows only 2 sockets .... one for the 4 and one for the 8
     
  10. skylar coy

    skylar coy

    16
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    Apr 29, 2017
    They are labeled but the sockets are labeled 16 and 8 ohm not and 8 and 4.
     
  11. davenn

    davenn Moderator

    13,502
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    Sep 5, 2009
    someone must have modified it
     
  12. skylar coy

    skylar coy

    16
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    Apr 29, 2017
    Okay. I just want 8 and 16 ohms. Tell me how to accomplish that and ill be good.
     
    Last edited: Apr 30, 2017
  13. skylar coy

    skylar coy

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    Apr 29, 2017
    It has been modified from its original but I want to return it to stock. Someone who is good with schematics please do tell. I am trying to wire the output transformer back to how it is supposed to be. What wires need to go where. I have one output jack with 2 terminals and one with 3. I am assuming that com goes on the 3. Note that red goes to a feedback thing and I know that the red one is fine. I just need to know where the black, grey, and brown wires go. also, right now the com is going to the output jack and it says it needs to go to ground. For the other three wires to go to the jack that will need to go elsewhere, where? Thanks!

    [​IMG]
     
  14. AnalogKid

    AnalogKid

    2,338
    654
    Jun 10, 2015
    You don't say anything about how the two output connectors functioned when they were "stock". It looks like one is connected to the 8 ohm tap through a switch in the other that also connects to the 4 ohm tap. How are the two connectors labeled on the outside of the unit, and is there anything in the manual about what is supposed to happen if both connectors are used.

    Also, not the best schematic symbol for the connectors. It is not clear which are the tip, ring, and switch contacts. Photos of the connectors?

    Finally, how are things connected in the non-stock configuration?

    ak
     
  15. skylar coy

    skylar coy

    16
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    Apr 29, 2017
    The two connectors are oddly enough labeled 16 and 8, and I would like to get it back to stock so whatever the schematic says. the jack that is labeled 16 ohms has two connectors on it, and has the 4 ohm wire going to it and then the other connector has a wire going to the 8 ohm labeled output jack. the jack labeled 16 ohms however has com going to it, the wire bridging the two jacks, a wire going to where the 16 ohm is conencted shown in picture and thats it. 16 ohm is going to FB 11 which is a part of a feedback thing and 8 ohm is sitting by itself on a terminal with nothing connected to it. Red is 16 ohm, grey is 8 ohm, brown is 4 ohm, com is black. I am not sure what this switch you are telling me is about.

    [​IMG]

    [​IMG]

    [​IMG]

    (notice the brown wire next to the red)
     
    Last edited: Apr 30, 2017
  16. AnalogKid

    AnalogKid

    2,338
    654
    Jun 10, 2015
    In your first photo, the jack o the upper right is similar to this:

    [​IMG]

    The hole is the sleeve contact. Notice to the right that the tip contact has an extra piece of metal touching it. That is the switch pin. The tip and switch are a normally-closed SPST switch. When you insert the plug it moves the tip contact away from the switch pin, opening the switch. This is a very common part, often used to divert an audio signal from the speakers when you plug in headphones. In your case it is doing something to manage two output impedances and the way they interact with the speaker. The problem is that the schematic symbol is not at all clear about which part of the connector is which.

    Although none of these is exactly correct for your part, here are examples of correct, unambiguous schematic symbols:

    [​IMG]

    ak
     
  17. skylar coy

    skylar coy

    16
    0
    Apr 29, 2017
    What is my amp wired to do right now? The 16 ohm is where is should be I think but what is it doing now with the 8 ohm connected by it self to one terminal, 4 ohm going to one, and a wire going off the 16 ohm to the other jack. Both jacks are connected to eachother. Just a bit confused. How can I test to see the current impedance of each jack
     
    Last edited: Apr 30, 2017
  18. Audioguru

    Audioguru

    2,744
    621
    Sep 24, 2016
    On the schematic why did they write "f.b." instead of the clear word "feedback"?
    You need to feed a high current signal into the wires on the output transformer to calculate the impedance which is difficult. Instead simply measure the resistance to ground of each output. 4 ohms will be the lowest and 16 ohms will be the highest.

    Here are schematics and terminals of switched jacks:
     

    Attached Files:

  19. skylar coy

    skylar coy

    16
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    Apr 29, 2017
    So how do I hook it up like the original schematic. I already know red is 16 ohms grey is 8 brown is 4. Red is already where it should be.
     
  20. Audioguru

    Audioguru

    2,744
    621
    Sep 24, 2016
    The schematic shows where the wires should be connected. The switch on the jack is shown when no plug is inserted thyen the top jack is 8 ohms. When a plug is inserted into the bottom jack then it becomes 4 ohms and the top jack is disconnected.
     
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