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  • tube amp power transformer?

    Hey All,

    I have an epiphone Galaxie 10 tube amp. It recently sounds all synthy and electronic. Would like 12 V to the heaters cause that? I think I need a new power transformer...

    Any help would be appreciated.


  • #2

    If what you have corresponds to this two tube schematic, no, it does not look like there should not be 12 volts from the heater supply. According to the schematic, there is a single dedicated transformer winding to power all heaters at 6.3V. 

     

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    • vanistheman
      vanistheman commented
      Editing a comment

      Yes that is the one I've got. So do you think I have a bad transformer?

       

      Thanks for the help.


    • r0bo01
      r0bo01 commented
      Editing a comment

      Kazinator wrote:

      If what you have corresponds to this two tube schematic, no, it does not look like there should not be 12 volts from the heater supply. According to the schematic, there is a single dedicated transformer winding to power all heaters at 6.3V. 

       

       

      i had always thought that if the tube name starts with a number, that number is its heater voltage (as told to me by my old radio repair boss..).

      but, it seems that a 12ax7 (per the above schematic) can run 6.3v as well as 12v: http://html.alldatasheet.com/html-pdf/121279/GEC/12AX7/52/1/12AX7.html

      schem doesn't show filament hookups, but looks like both 12ax7 & 6l6 are running off the 6.3v heater secondary with12ax7 using parallel heater connection (it's a dual triode) @ 6.3v instead of series @ 12v.

      so i've learned something new as well...


  • #3

    vanistheman wrote:

    Hey All,

    I have an epiphone Galaxie 10 tube amp. It recently sounds all synthy and electronic. Would like 12 V to the heaters cause that? I think I need a new power transformer...

    Any help would be appreciated.


    I don't know what "synthy" and "electronic" means (show me a guitar amp that isn't electronic), but whatever it is, the tone is off.  Tone being off happens to every guitarist.

    It's either you, the equipment or some combination of both.

    The first thing is to do the basic maintenance.  Clean and lubricate all of the jacks, plugs and potentiometers, in the guitar and amp, and any effects pedals in between. Bad tone can easily come from poor contacts in these parts: contacts which are good enough to pass signal consistently, just with degraded quality. You can also clean the tube sockets, and any internal connectors within the amp.

    Are you going straight into the amp or through some pedals? If so, how are they powered? If they are on batteries, how fresh are the batteries?

    Do you have active or passive pickups, and if the former, how are the batteries?

    Environmental factors can affect sound, like air temperature and humidity. Speakers are made of paper, and work best when they are dry.  Has there been a weather change recently where you live?  I keep about two tennis ball sizes worth of silica gel dessicant wrapped in a cotton cloth inside my 4x12 cabinet to help ward off moisture. The stuff is available as kitty litter in any pet store or pet section of a big grocery store.

    Amp tone is sensitive to the room, and where you sit or stand relative to the amp. Have you moved around furniture lately, or repositioned the amp, or your playing position?

    You should get to know your amp's "baseline" tone. Spend some time on a regular basis playing with the amp lifted up and aimed at your face. In the future, when you're "debugging" tone problems, try to use the memory of that as your reference, otherwise you're distracted by room acoustics.

    If you have a mic and some recording gear, record some samples. Always use the same mic position. If the recording on a "bad tone" day sounds exactly the same as the one you made on a "good tone" day, the diffrence is in your ears or brain, or else a real acoustic difference that is picked up by your ears but not by the microphone.

     

    <div class="signaturecontainer">Music DIY mailing list: <a href="http://www.kylheku.com/diy" target="_blank">http://www.kylheku.com/diy</a><br><br>ADA MP-1 mailing list: <a href="http://www.kylheku.com/mp1" target="_blank">http://www.kylheku.com/mp1</a></div>

    Comment


    • BackTrack
      BackTrack commented
      Editing a comment

      New here, so, hello.

      One thing that drove me crazy was trying to find the reason for a similar issue I had. It turned out to be the ceiling fan. The blades reflected the sound and made it synthy sounding, especially on higher notes. Just my .02

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