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B+ = 510volts :(

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  • B+ = 510volts :(

    Hey all,
    This is my first build so im still in the learning process but when I first powered up my amp like a dummy I didn't check any voltages and notice for one I obviously had no sound. Secondly I noticed one power tube was dimmer than the other. So I went about unsoldering eeverything and noticed I had a cold solder on my filament wire to one of the power tubes. I resoldered everything almost with a new soldering gun to make sure It was all good before I powered up again. When I turned it back on after working on it I still had no sound. I checked my power transformer and some other things to make sure all was still well and all checked out. I have 350v DC coming off of my rectifier but when It gets combined with the output tranny at the standby the voltage jumps to 510 at b+ And plate voltage of power tubes. I went to read how biased it was and it was 0.??? Power supply caps shot? bias off? recto not good enough? This is what I have come up with but im just grabbing for straws here lol. Thanks for even letting me post and ask this I love you all and how awesome it is to be able to connect to each other.

    nate the red fox
    ?

  • #2
    Can you post a schematic?

    Comment


    • #3
      You should mention what amp model this is. Providing a schematic would be even better. The schematic should represent your actual amp and NOT a "similar" amp followed by a text description of the differences. High res photos would be icing on the cake. Voltage readings at each power tube pin and power supply node are necessary.

      My only guess at this time is that you have a mistake in the HV rail wiring (the B+ supply circuit). There may be a cap floating, combined with a miswire.

      Is the amp grid biased or cathode biased?

      Is the amp using a diode or tube rectifier?
      "Take two placebos, works twice as well." Enzo

      "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

      "If you're not interested in opinions and the experience of others, why even start a thread?
      You can't just expect consent." Helmholtz

      Comment


      • #4
        Originally posted by Chuck H View Post
        You should mention what amp model this is. Providing a schematic would be even better. The schematic should represent your actual amp and NOT a "similar" amp followed by a text description of the differences. High res photos would be icing on the cake. Voltage readings at each power tube pin and power supply node are necessary.

        My only guess at this time is that you have a mistake in the HV rail wiring (the B+ supply circuit). There may be a cap floating, combined with a miswire.

        Is the amp grid biased or cathode biased?

        Is the amp using a diode or tube rectifier?
        Model is 5e3 tweed deluxe http://site.triodestore.com/5E3_Layout_Diagram.bmp is the layout diagram pic was too big to post and the schematic is fender Deluxe




        5y3gt sovtek
        4-344
        6-344

        6v6s jj
        1-0
        2-2.9
        3-514
        4-0?
        5-6.7mV?
        6-0
        8-483

        6v6s 2
        2-3
        3-518
        5-3mv?



        12ay7 electro harmonix
        1-446
        2-0?
        3-3
        4-0
        5-3
        6=555
        7-4
        8-133
        9-3


        12ax7 jj
        1-446
        2-3
        3-7
        4-246
        5-3
        6-392
        7-0
        8-7
        9-3

        I just tested with two NOS 6v6 I got and read 524 plate voltage
        Attached Files

        Comment


        • #5
          also tube rectified w/ sovtek 5y3gt

          and I believe its cathode biased

          Comment


          • #6
            OK, in the layout, the sockets for the 6V6s show pin 1 and 8 as to the lower right. But we can see the tube base pins index key pointing upper left in the photos. And I think you have seriously mis-wired the sockets. The brown and blue transformer wires do appear to be on pins 3 correctly.

            Pin 1 left empty - OK.

            Pins 2 and 7 look like they are right, if both tube heaters light, then they are,

            Pins 4 are wired together, but they are then wired up to the cathode resistor and cap on the left end of the board. That is wrong. They should be wired up to the center of the three large black caps.

            Pins 8 are wired together, but then they are wired to that capacitor where pin 4 goes, and they should be wired to the smaller cap and cathode resistor on the left.

            In other words the pairs of pins 4 and pins 8 were each wired to the others place on the eyelet board.

            Pin 6 is not a tube element, it is just a handy place to solder something. Pin 5 is the control grid. Your 1.5k grid stopper resistor is soldered between pins 5 and 6 OK, but you have the wires from the circuit coming up to the pin 6 end of each. It should go to the other end of each. Look on the layout. They have the resistor on the top side of the socket with the wire on the right end. Your socket is upside down from the drawing so the resistor is on the other side, but you still put the wires to the right instead of left.

            It is OK if you install the sockets facing the other way, but you have to make sure all the wires still get to the correct pins.
            Education is what you're left with after you have forgotten what you have learned.

            Comment


            • #7
              All and ENZO,

              I had noticed the yellow wires before I left home today but no time to fix them till now and great eye on the other wires I tried to account for that but I guess it got the best of me. I fixed those and I still had no sound but after a little moving one wire on my volume pots I heard my darling sing for the first time I felt satisfaction like you would never believe!!!!!!! . MOST OF ALL I REALLY AND TRUELY WANT TO SINCERELY THANK ALL OF YOU THAT HELPED ME ON THIS!! I HAVE TO THANK THE ALIGNMENT OF THE STARS AND EVERY CONSTANT OF THE GALAXY FOR YOU GUYS AND THE WAY THE INTERNET HAS BROUGHT US ALL TOGETHER AND CLOSER THAN EVER. YOU GUYS ARE SAINTS FOR HELPING LIL OL ME LOL. I REALLY DONT KNOW HOW TO THANK YOU ENOUGH. IM GONNA FIGURE OUT SOME WAY TO REPAY YOU . I HOPE YOU GUYS HAVE A WONDERFUL DAY FOREVER AND MAY COSMIC KARMA LET YOU KNOW HOW TRUELY HAPPY YOU GUYS HAVE MADE ME.

              THANKS A GAGILLION
              NATE the red fox TOWNSENDClick image for larger version

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              • #8
                now I can finish my cab and get her screaming lol

                Comment


                • #9
                  Be sure to follow up on EVERYTHING mentioned in Enzo's post. You'll know soon enough if it's just making some sound or working "right". We're always here
                  "Take two placebos, works twice as well." Enzo

                  "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                  "If you're not interested in opinions and the experience of others, why even start a thread?
                  You can't just expect consent." Helmholtz

                  Comment


                  • #10
                    it has been a crazy time lol cause I didn't buy a chassis I bought a busted 50 watt crate tube head and chopped the chassis down and did my thang inside of it so I did a lil riggin lol but im feeling like shes gonna be real nice

                    Comment


                    • #11
                      yea I definitely went out on a limb with doing so much fabrication on my first build by sticking it in another chassis than it was meant for but hopefully I got it ill post finished results when I get her and my speaker in a cab thnx again.

                      Comment

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