Announcement

Collapse
No announcement yet.

5F10 Harvard Homebrew Complete

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

  • 5F10 Harvard Homebrew Complete

    Chassis up and running , have not completed the cab yet. Sounds wonderful. The soldering around the bias supply is a bit messy as I had to do lots of fudging around with resistors to get the voltages right. I had to build a bias supply off of a rectifier pin socket as the PT I used did not have a tap for one, was a bit of a chore but it all worked out in the end. I may clean it up a bit later but as it's running perfectly fine I may just leave it be.

    I am going to play it for a while with different speakers to see if I want to go with a 10 or a 12 inch speaker.

    Here are a few pictures.

    Alby.

    http://photoshare.shaw.ca/messages/v...904/page/1/15/

  • #2
    Good job!

    Hey-
    That's a great looking amp in the works!
    Are you building a stock Fender cabinet or a custom?
    If you don't have dimensions for a stock cab, I can help you out.
    You probably know this already, but it has the same size cabinet
    (but with a 10" speaker)as a Princeton,
    and I have an original.
    Did you build the chassis yourself? It looks awesome!
    I have been wondering for a while what a Harvard sounds like!
    Make sure you post more pics as you go.
    Chaeck out some of my cabinets in my posts.

    Comment


    • #3
      The chassis I had bent and did the rest at home. I am really enjoying this amp so far.

      Thanks for the offer and I would appreciate some dimensions as I am trying to make the cab as close as possible to the original. Most of it I am pretty sure on I just need the exact dimensions for the back panels, especially the size and spacing for the tube heat venting cutouts and back panel hights.

      Alby.

      Comment


      • #4
        Harvard/Princeton Back Panel Measurements

        On my particular amp the upper back panel is 6-3/4" tall (keeping in mind that the tweed takes up about 1/16" per edge on all measurements)and 16-1/4" wide.
        the vent hole is 1-5/16" from the bottom edge and 1-5/8" from the side edge
        (on mine the right edge is actually 1-3/4" from the side edge-and it is an original '59 model, so take your pick
        The vent hole itself is 6-1/4" wide and 1-1/4" tall.
        One thing I've noticed on old tweeds is that the top of the vent is always at the bottom of the chassis within 1/8" or so-which makes sense.
        The round over on the inside vent edges is 1/2"
        rounding over 1/4" plywood with a 1/2" bit is tricky, but with a thick template it can be done easily.
        Good luck and let's see some photos!
        WT

        Comment


        • #5
          Thanks WT, Just what I was looking for. It's reallly important to get the vent measurments correct or it just does not look right.

          I have done the bevel on the back panels before, I did them by hand with various files and sandpaper. Takes a fair bit of time but it has always worked for me. I may try building a jig some day for my router.

          I will start on the cab this week and see how far I can get over the next 2 weeks at which time I will have to put down the tools for a week of fun and music in Austin Texas.

          Alby.

          Comment


          • #6
            The chassis looks great. How did you do the lettering? Looks very nice.

            Comment


            • #7
              Wow very nice! What kind of transformers did you use? I want to build a Harvard after I finish the 5F6A I am currently working on.

              Comment


              • #8
                What a cool project. Harvards are so sheik. Looks great!

                I am also interested in how you did the lettering.

                Comment


                • #9
                  You can see in the first few photos, I used a rub on product called Letraset. It's kind of obsolete now but if you can get some it works great. You have to very patient and have a steady hand, I made a jig for the numbers, you can see it in the pictures.
                  The transformers are the normal Hammond ones used for a 5E3. The PT don't have the bias tap so you have to incorporate that into the circuit board.The voltages and output are higher than stock but it works and sounds fantastic.

                  I am starting the cab this weekend. I will update the link above with new photos once it's complete.

                  Alby.

                  Comment


                  • #10
                    Harvard 5F10 clone

                    Great job on the Harvard. I just finished a 5f10 clone too. Unfortunately, I'm having problems getting anything out of it (so I guess not finished). Apparently there is a short somewhere as I'm either instantly blowing the fuse or tripping the GFCI equipped outlets. For three days I've checked my wiring against the fender schematic and layout and also enlarging your photos (very nice documentation, Thanks!) and comparing to them. I just don't see where my circuit is in error. I have never had a defective PT before but I'm starting to wonder if thats the problem. Anyone know how to test one? It's a Weber made to fit a Deluxe, but has a set of lower voltage taps that are about right for a Harvard (270-0-270), and also a bias tap. I'm really bummed because I've been intrigued with the Harvard for about a year, so I'm dying to hear what it sounds like.

                    Comment


                    • #11
                      Sorry your having start-up issues, keep at it, there is nothing that can't be figured out if you use a methodical troubleshooting plan.

                      Start a new thread with a link to some detailed chassis shots and you will get lots of friendly help for the great people here. Make sure you give as many details as possible with regard to what you have done or not done in your troubleshooting process.

                      Dont forget the pictures, it really helps.

                      Alby.

                      Comment


                      • #12
                        Originally posted by Edgar Sterling View Post
                        Great job on the Harvard. I just finished a 5f10 clone too. Unfortunately, I'm having problems getting anything out of it (so I guess not finished). Apparently there is a short somewhere as I'm either instantly blowing the fuse or tripping the GFCI equipped outlets. For three days I've checked my wiring against the fender schematic and layout and also enlarging your photos (very nice documentation, Thanks!) and comparing to them. I just don't see where my circuit is in error. I have never had a defective PT before but I'm starting to wonder if thats the problem. Anyone know how to test one? It's a Weber made to fit a Deluxe, but has a set of lower voltage taps that are about right for a Harvard (270-0-270), and also a bias tap. I'm really bummed because I've been intrigued with the Harvard for about a year, so I'm dying to hear what it sounds like.
                        Since you didn't mention, I'll ask the dumb question: have you tried swapping tubes? A bad tube can cause a fuse to blow.

                        How did you check the wiring? By inspection, or with a meter?

                        If that's not it, then try switching on with all the tubes pulled out, check voltages and condition of fuse. Then switch off, put the rectifier in, switch on again, and check everything. Work your way down the line checking voltages to ensure that they look normal.

                        Comment


                        • #13
                          Thanks, I will start a new thread as soon as I find a place to post some pictures. But for now I will just mention that I swapped out a known good transformer for the new one and the amp works perfectly. The only difference (perhaps a big difference) is that the transformer doesn't have a center tap, or a bias supply tap, so for the moment the "Harvard" is operating as a cathode biased, fullwave bridge rectified amp (I'm thinking the fixed-bias of the Harvard will give it a unique tone compared to other small amps).THis at least proves that the circuit (minus the fixed-bias section and the tube rectifier) is operating correctly. As far as the rectifier tube, I tried others, and with no tube at all and got the same results. I'm quite certain the rectifier socket was wired properly. That narrows it down to the PT or the way it was wired.

                          Comment


                          • #14
                            Oh, and Alby, I hope you will post pictures of your cab when you finish it. I'm still thinking about that part.

                            Comment


                            • #15
                              Updated photos with completed cab and assembled amp.

                              Link at top of thread.

                              Alby.

                              Comment

                              Working...
                              X