One speaker quieter than the other

Discussion in 'Audio Hardware' started by Seagarth, Feb 5, 2016.

Thread Status:
Not open for further replies.
  1. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    Using the tape out RCA jacks on the back of amp?

    If that is the case, the tape out jacks are not part of the signal path of the preamp section of the amp.
     
  2. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
  3. KT88

    KT88 Senior Member

    It's a great excuse to buy a new amp. The Rega Brio-R is a much better amp. It's also entirely designed and built in England, if that matters to you.
    -Bill
     
    Colin M likes this.
  4. Vinyl Addict

    Vinyl Addict Forum Resident

    Location:
    MA
    That won't make a difference, I wouldn't think anyway. Is the longer wire connected to the quiter speaker? Or is it the other?
     
  5. Seagarth

    Seagarth Member Thread Starter

    The headphone amp is connected to the 'Rec Out' jacks.
     
  6. Seagarth

    Seagarth Member Thread Starter

    The longer wire is connected to the right (louder) speaker. However, even when I switch the wires and speakers it is always the case that the quieter speaker is linked to the left output at the back of the amp.
     
    Vinyl Addict likes this.
  7. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA

    Seagarth said:
    The headphone amp is connected to the 'Rec Out' jacks.

    //

    Seagarth,

    The (Tape Out) jacks are ahead of the preamp section of the integrated amplifier.
    I suggest you try the headphone amp, connected to the Tape Out RCA jacks again to make sure the sound from Left channel is lower the right.

    If the sound is lower in the left channel, through the headphone amp/headphones, then the problem is therefore ahead of the preamp section of the Cambridge A1 amp.

    I tried to find a schematic wiring diagram for the A1 with out any luck.
    Tape Monitor circuits are pretty the same who ever the manufacture is.

    Take a look at this schematic wiring diagram of an ARC LS3 preamp.
    (Drawing is for the right channel.)

    http://www.audioresearch.com/ContentsFiles/B SchPL.pdf

    Look to the upper right hand side of the diagram.
    Note the Line Level input RCA jacks at the very top of the diagram.
    Note the SW1 source selector switch. This switch selects the source you want to listen to.
    Note the Tape Out RCA jack.

    As you can see the sw1 selector switch is ahead of the Tape Out RCA jack.
    The selector switch for this preamp is mechanical. Just a guess I would say the one in your amp is also mechanical. No guarantee though. For some reason Cambridge seems to love relays.

    IF the Left Channel of the common contact of the multi-contact is dirty or possibly corroded it is possible this is the cause of your problem.

    Temporary quick fix is to rotate the switch back and forth through all the selectors positions in a fast motion back and forth several times. Hopefully this will cause the friction rubbing action of the contacts rubbing against one another to clean the left channel contact/s
    You can do the process with the amp turn on or off.


    Take a listen to the Headphone amp to see if it solved the problem.

    If yes take a listen to the Cambridge amp.

    Note: if you go back to the ARC LS3 diagram the next switching after the source selector switch is the Tape Monitor switching circuit.

    Post back your results of the test.
     
    Last edited: Feb 7, 2016
  8. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA

    >>>>>>>>>>>>>>>>

    jea48 said:
    Look to the upper right hand side of the diagram.
    Note the Line Level input RCA jacks at the very top of the diagram.
    Note the SW1 source selector switch. This switch selects the source you want to listen to.
    Note the Tape Out RCA jack.
    As you can see the sw1 selector switch is ahead of the Tape Out RCA jack.
    The selector switch for this preamp is mechanical. Just a guess I would say the one in your amp is also mechanical. No guarantee though. For some reason Cambridge seems to love relays.



    "Look to the upper right hand side of the diagram.

    EDIT, correction:


    Sorry guys, that should read:
    Look to the upper LEFT hand side of the diagram.

    My Bad!
     
  9. Seagarth

    Seagarth Member Thread Starter

    If I understand you correctly (and remember that my knowledge of these things hardly extends past the surface details of the amp!) the switch I should rotate is the selector at the front- the one that selects the different sources i.e. phone, CD and so on. If so, I have done this, and I have tried putting the headphone amp into the Tape jacks but it's the same i.e. quieter in one (the left) ear.
     
  10. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    Then, ime, the problem is somewhere in the circuitry of the source selector switch, or the switch itself.
    Ime, it is not a problem with the preamp of the amp.

    One more test if you are up to it.

    Plug the Marantz CDP into the (Tape In) RCA jacks.
    On the front panel enable the Tape Monitor push button. Just a guess the button would be push in the half way in position.

    The signal circuit path will be from the CDP >> Tape In jacks >> to the tape monitor circuitry >> to the input stage of the Cambridge preamp. (This totally bypasses the inputs selector switch.)

    Turn on the amplifier and check how it sounds. If the tape monitor circuitry is ok the amp should sound ok. (If you do not hear any sound press the monitor push button on the front panel again to verify the switch, (possibly relay contacts), are closed completing the signal paths to the right and left input sections of the preamp.

    Post back your findings.
     
    texron and BuddhaBob like this.
  11. Seagarth

    Seagarth Member Thread Starter

    That's it! Both speakers have an equal volume now. What does this tell us then? Many thanks for your help.
     
    BuddhaBob likes this.
  12. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    Good to hear. At least you can now listen to your music through the amp and speakers.
    If you feel the need to listen through the headphone amp just plug it into the CDP RCA output Jacks.

    As for the fix of the selector switching of the left channel RCA inputs it could be just a cold solder joint somewhere between the left channel selector switching common and the input of the left channel preamplifier input section. ( That would be an easy fix.)

    If you had any experience trouble shooting cold solder joints, and, any hands on soldering skills/experience, I would say open up the unit and take a look inside. From reading your posts though I think you made it clear you would not know where to start.

    Maybe you have a friend that could look at it for you. He/she will need some soldering skills though.

    Unless you have more than one front end piece of audio equipment the Tape in RCA jack inputs may be all you need.

    .

    Below are some pictures suposedly of the inside of the Cambridge A1.

    Hard to tell from the picture/s but the source selector switch, (located on the left side of the balance control pot), looks to me to be a dual gang multi position mechanical switch. Hard to tell from the picture though. (Far left hand side is the Tape Monitor Push Button switch which also appears to be a mechanical switch. Just to the right of the tape monitor push button switch is the source input selector switch.)

    I am not even sure if it is a picture of your amp.
    http://img.canuckaudiomart.com/uploads/large/134134-cambridge_audio_a500_integrated_amp_remote_.jpg
    I see an orange color cable that has three wires, (black, red, and white), that connect to a plug in connector just slightly back from the selector switch and slightly to the right near the black heat sinks. It appears to come from the switch. The cable could very well be the right and left channels common outputs from the selector switch and plugs into the right and left input sections of the preamp. The contacts for the left channel could be dirty and or corroded.

    https://www.google.com/search?q=picture of inside cambridge A1 integrated amplifier&rlz=1T4GGLL_enUS413US413&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwidh_-An-vKAhUJQyYKHUyXChkQsAQIHA&biw=834&bih=589

    Jim
     
    Last edited: Feb 9, 2016
  13. Seagarth

    Seagarth Member Thread Starter

    That's really useful information Jim. Thanks. I will use this info to approach a technician and see if I can get it fixed. It's just good to be able to listen to my music properly in the meantime!
     
Thread Status:
Not open for further replies.

Share This Page

molar-endocrine