Announcement

Collapse
No announcement yet.

6505+ with EL34?

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

  • 6505+ with EL34?

    I know the 6534+ is Peavey's take on the older 5150II with EL34s but looking at the PCB for the 6505+/5150II power amp board the only problem seems to be the lack of a connection between pin 1-8 for V8, which is present in every other power tube. By connecting the V8 pins 1-8 (and modifying the bias circuit and SGRs) this amp should work fine with EL34's right?

    see here

  • #2
    Originally posted by tedmich View Post
    I know the 6534+ is Peavey's take on the older 5150II with EL34s but looking at the PCB for the 6505+/5150II power amp board the only problem seems to be the lack of a connection between pin 1-8 for V8, which is present in every other power tube. By connecting the V8 pins 1-8 (and modifying the bias circuit and SGRs) this amp should work fine with EL34's right?

    see here
    Theoretically it will work with 220 K bias splitters, 1K screen grid resistors, and pins 1,8 tied to ground, as long as you bias it...
    but sometimes those boards burn, i suppose when the output impedance is mismatched.
    you can tie pin ones to bias and it will draw less current, but I don't know if it sounds as good...

    Comment


    • #3
      Well, if yo0u did that, you would then have to lift the other three pin 1s to similarly connect them.



      Yes, jumpering to that one lonesome pin 1 will do it, as long as you make the other changes.

      And the stock power transformer has more than enough oomph for the additional heater draw. Remember EL34 draws 1.5A heater, while the 6L6 draws 0.9A.


      Meanwhile, where did you get that layout drawing? It is not the same as my 6505+/5150-2 layouts.

      Look at the layout for the 6534. It is the same drawing as yours, but with the link from pin 8 to pin 1 included. If you look close, you can see the link is added to the basic drawing. On both side views.
      Education is what you're left with after you have forgotten what you have learned.

      Comment


      • #4
        Originally posted by Enzo View Post
        Well, if yo0u did that, you would then have to lift the other three pin 1s to similarly connect them.



        Yes, jumpering to that one lonesome pin 1 will do it, as long as you make the other changes.

        And the stock power transformer has more than enough oomph for the additional heater draw. Remember EL34 draws 1.5A heater, while the 6L6 draws 0.9A.


        Meanwhile, where did you get that layout drawing? It is not the same as my 6505+/5150-2 layouts.

        Look at the layout for the 6534. It is the same drawing as yours, but with the link from pin 8 to pin 1 included. If you look close, you can see the link is added to the basic drawing. On both side views.

        this is just the PCB from the 5150 II schematic I have, although the traces were very faint and I needed to up the contrast in Photoshop, I have never seen or found the 6534 schematic/PCB layout, it would be useful...

        To be clear the "other changes" you mention include "lifting other pin 1 to similarly connect them" meaning what exactly? It should just look like the 6534; with the V8 pin 1 and pin 8 connected right?

        Comment


        • #5
          SGM suggested connecting that loose pin 1 to bias. I countered that if you did that, you would then have to isolate the other three and similarly wire them. My comment was only meant as a reply to him, NOT a suggestion.

          You can get any PV schematic from PV by asking customer service, you don't have to "find" them.. Your image is exactly that from the 6534 set except the 6534 has the added jumper.

          Does that layout drawing look exactly like your 5150-2? If it does, great. MY only question was where did you get that drawing. My factory copies for the 5150-2 do not look like that. The 5150 and 5150-2 used the same 6L6 board, at least originally. I must presume that they may have changed production and are using a different power tube board in the 5150-2 now. For example, in your drawing there are two screen resistors crosswise in the center, while on the old 5150 board there are four of them all lined up along one edge of the board.

          As long as you get where you need to be, we are fine. I am asking all this as an acedemic interest.


          Here, I attached the 6534 set, and for reference the 5150-2 set. See how my 5150-2 differs from yours?
          Attached Files
          Education is what you're left with after you have forgotten what you have learned.

          Comment


          • #6
            Enzo thanks as always!, my 5150 II pdf is 1.8Mb and has quite a bit more PCB detail, can't remember where I got it.

            The schematic 1st page is identical to yours, but higher res. The pdf I have was created 3/17/2004 at 2:13:15 PM, if that helps...

            https://docs.google.com/open?id=0Bx4...2V6ZWJNVW9yTm8

            wonder how to attach here....oh well

            Have an extra big PT/OT so I might turn a 6505+ 112 cheapy into a 120w 6505/34+ 112
            Last edited by tedmich; 07-06-2012, 12:43 AM.

            Comment


            • #7
              A 'Vega' funny car!
              Holy Sh*t.

              Comment


              • #8

                Vega

                other one is a Pinto!

                (both are silly)

                Comment


                • #9
                  Here is the file in the link.
                  I downloaded then attached it.
                  T
                  peavey-5150-ii.pdf
                  "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
                  Terry

                  Comment


                  • #10
                    Oh, well there you go. Your drawing set includes both versions of the power tube board. The newer on is dates 2001. I've never seen that until now. Thanks.
                    Education is what you're left with after you have forgotten what you have learned.

                    Comment


                    • #11
                      Repost of the 6534 schematic:

                      PV 6534.zip

                      Comment


                      • #12
                        Careful, you've exhumed SGM

                        Comment


                        • #13
                          Originally posted by Dave H View Post
                          Careful, you've exhumed SGM
                          Custom ceramic caps in a Marshall!!!! The owner of Tennis.coms house! Every 5150 blows up like that!!


                          (spooky!)

                          Comment


                          • #14
                            Originally posted by tedmich View Post
                            Custom ceramic caps in a Marshall!!!! The owner of Tennis.coms house! Every 5150 blows up like that!! CRATEPEG! CRATEPEG! CRATEPEG! CRATEPEG! GO BUY A REAL AMPEG! Bias your amp with a hammer!
                            Jusrin
                            "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
                            "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
                            "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

                            Comment

                            Working...
                            X