Ad Widget

Collapse

Announcement

Collapse
No announcement yet.

Lost 6.3volt center tap now I have hash and an ugly sounding amp

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Lost 6.3volt center tap now I have hash and an ugly sounding amp

    I recently upgraded the caps for a blues jr. and it sounded great, but I had also lifted the 47ohm resistors for the center tap heater supply, off the board and to ground supposedly to reduce hum. It seemed to work great, amp sounded great, no hum, with better caps, then bam, the amp has cruddy sounds coming thru when hitting notes, hash, just not a good sound. I suspect since I lifted the wrong end to ground, yes I did, ouch, I fried the power transformer heater circuit. Can an amp still work without the center tap for a spell, only to crap out, and still play notes, but ugly notes?

    I have tried everything I know to get rid of this problem, so I know now that the 'mod' I did and screwed up most likely spelled the end to that transformer....any reassuring comments are welcome…
    JrL

  • #2
    Measure the heater supply.
    Volts AC.
    If it is 6.3 volts, look elsewhere for the problem.

    Comment


    • #3
      Voltage check 7.24vac

      I did the check this morning, pulled the two green leads from transformer and checked without a load, and the digital meter says 7.24volts. I have heard anything above 7volts ac isn't good, so would this indicate some sort of heater transformer malfunction? as I do electrical design work for a living, mostly higher energy, I do know some things about this business of transformers, but small amps I am learning the ins/outs of.
      Since I didn't do a baseline before all this, I wouldn't know if this was the original value, or something I did.

      Comment


      • #4
        6.3 volts with a load

        I put the tubes back in and the circuit is 6.3volts dead on...okay, next. I did remove and add some caps/resistors, so Iwill go back and resolder these, I figure now it is a connection problem, not quite solid, as I get amplification, but it has distortion on the signal when striking a note, and it isn't the good stuff, even at low volumes.

        Thanks for listening.

        Johnne in Seattle

        Comment


        • #5
          It was the coupling caps

          I guess I must have had some bad caps, did take out three coupling caps and replaced with better caps, and now the problem has gone away...good deal, now to put together that Tweed twin...

          Comment

          Working...
          X