Ebay Classic organs



No announcement yet.

1954 C-2/ Has anyone installed AO28 for percussion?

  • Filter
  • Time
  • Show
Clear All
new posts

  • 1954 C-2/ Has anyone installed AO28 for percussion?

    Hello...I just subscribed to this forum so this would be my first post.

    Just last night I acquired a 1954 Hammond C-2. Everything works great...but of course I miss not having percussion.

    I have a working A028 preamp that I would like to install in this if it is not too much trouble. I realize I will be needing percussion switches but that is not an issue... I have some from a parted M-3.

    I am aware that installing a Trek percussion unit might not be a bad idea but since I have the preamp already I probably trust it because I am familiar with the percussion sound from them. I have not heard the Trek. I tend to like the slow decay sound and I am not sure the Trek would sound the way I am used to.

    If anyone has done this I would like to hear about it. Or your thoughts on the Trek percussion if you have done that.

    What do you think?

  • #2
    On a 2-series organ, I would use the Trek II percussion unit and your AO10.

    Even if you have the Percussion Switches from an M3, where are you going to put them? Every time I've seen someone try to retrofit Percussion Switches into a metal 2-series drawbar base, the results have been awful-looking. And you'd have to relocate the Start/Run switches.
    I'm David. 'Dave' is someone else's name.


    • #3
      Sell the pre-amp and buy the Trek II percussion. You can tune it how you like - many more options on the Trek unit.


      • #4
        I have done what you are contemplating. It's a bit of work, but it dosn't have to look awful, and works perfectly. I wanted the organ to be as near a real b3 as possible, with all controls Hammond and where a player expects them to be. Besides, my TrekII money needs to go for the string bass board. Moving the start switches is the easiest part of the project.


        • #5
          Thanks Ted....I might want to know a bit more about how you did your preamp swap. I was hoping to chat with someone who had done it.

          As far as where switches would go......its not a big deal. This is not a gigging organ so I would get to that later.

          As far as the Trek percussion... I am just not sure if it wouldn't sound a bit different than the original. Most people like fast decay. I do not.

          Also ... money is an issue and I already have the preamp. I am not set up on ebay...or "Pain Pal" which I hate. Ebay seems to be the only place to sell a preamp.

          So yes ... I might need some info on what goes where... and why.


          • #6
            So anyway...this is an extremely nice C-2. It was in a local piano store in Salem Oregon. The owner could just not sell it. It came with a PR40. He wanted the space back so bad he delivered it !

            It looks as though it was almost unplayed. There is no noise in the manuals. and very little if any wear on the bench.

            This will be my first experience with an organ of this period. I like the sound of the older line box... it seems to have less ''throb'" than the later type. There also seems to be a bit more keyclick. So it is not unlike the 2 series organ Jimmy Smith made famous on "The Sermon"..

            One thing I have always noted about 2 series is that they have that rock and roll overdrive if you crank the preamp volume. It's different than a B-3. Not sure how old the tubes are, but I do love the simplicity of the A0 10. So there is one reason to consider the Trek II

            Anyway I am enjoying this and I am finding non percussion settings which I need to know better anyway.


            • Sweet Pete
              Sweet Pete commented
              Editing a comment
              At the ***K Cancer show featuring many of Canada's best known acts,at the Hard Rock Theatre Oct 1 2022?
              Bragging rights to the furniture at the show all mine.The monitor desk is a Midas Heritage....floor wedges Meyer and FOH by dB and Digico.
              1953 B2 with smooth drawbars and a TrekII TP2B.Pair of pre70 Leslie 147,stock.One isolated for mics.
              Gone Gone Gone.....Workin' For The Weekend.....Doin' It Right....Raise A Little Hell! Encore?
              Mama Let Him Play!

          • #7
            I also have retrofitted an AO-28 into an older organ (but not a -2 series, in my case it was a BC). Are there any specifics that you're wondering about? Mostly it's just about wiring it up according to a -3 series schematic... not very difficult at all.
            Current organs: AV, M-3, A-100
            Current Leslies: 22H, 122, 770


            • #8
              I do know people who understand schematics but I do not.

              First question would be... how do the existing wires from the C-2 correspond to the AO28?

              If I get those connected then I assume the organ should at least work

              ​​​​​​​After that then I will address the percussion switches.


              • #9
                This B2 has a TrekII TP2B percussion.Installed it in 1999.Has been working flawlessly ever since.
                Have a qualified technician explain the hazards of working on high voltage vintage electronics and go over your mechanical fittings before you ix-ney the TrekII.
                Circuits left live unused are not recommended in any application,let alone a 70 year old instrument.

                If you are qualified like enor then fine go for it.If you are a novice with a jones for percussion do yourself a favor and just install the TrekII.
                Originally disappointed with the ergonomics but eventually grew to like it a lot,and can once again use 2nd/3rd together like my beloved M102!

                That AO28 'you already have' will easily DOUBLE your expenditures by the time it's all done and buttoned up unless you are qualified.
                A100/251 A100/147 A102/222 B2/142 BV/147 BCV/145 M3/145 M102/145 M111/770 L101/760 T222/HL722 M111/770 no B3/C3!


                • #10
                  The Trek-II TP2B can have longer decay or shorter decay than an AO28...whatever you want...and its available at the touch of a finger. It's also a VERY easy install, and the AO10 is the best-sounding preamp Hammond ever made. The only drawbar to the TP2B is that there is no off switch (although you could always add one - I have one up near my power switches).

                  The AO28 can be made to work, but if you can't read a schematic, you will find this challenging.

                  Note that if your AO10 is revision A, B, or C (fact check Enor?) you will have to replace the matching transformer with one from an AO28 organ.


                  • enor
                    enor commented
                    Editing a comment
                    Not necessarily from an AO-28 organ; one from a newer -2 series will do as well (one with preamp rev D-E-F-G)

                • #11
                  OK.... a couple of people have posted that they were able to install an A028 into a C-2

                  It's a matter of finances right now I live in an area where there are a lot of homeless people and they like to do things like smash windshields. Which is what happened to mine.

                  So I have to choose between a windshield and a Trek II percussion unit.

                  I do have some qualified help by the way. McIntosh Audio is close to where I live and he is willing to help me. He is the service tech for Hammond Suzuki, Crumar Mojo, Viscount, HX3 Keyboard Partner etc.etc.He is a good trusted friend and does work at reasonable prices.

                  What I might be able to do is take an A)28 and the A010 to his shop and compare similarities. I also have heard that something is connected to the matching transformer..and that is also true of the Trek unit..

                  My eventual goal is to make this into a stock C-3... for all intents and purposes.For now I just want to get percussion with what I have to work with


                  • #12
                    To do a neat installation of AO28 percussion into a 2-series organ, you really need a metal drawbar base from a 3-series organ into which to mount the percussion switches.

                    Although the AO10 uses octal tubes while the AO28 uses miniature types, the main audio circuitry of the AO10 and AO28 are, for the most part, pretty much identical. The AO28 is the AO10 with percussion added.

                    In terms of price, it's relatively simple to install the Trek II percussion unit. Installing a new drawbar base and wiring the percussion switch and the AO28 into the C2 will require a lot more time and, thus, more labor cost than a percussion unit installation. So I'm not sure which option would end up being less expensive in the end.
                    I'm David. 'Dave' is someone else's name.


                    • #13
                      Even if you'll spend a bit more on a drawbar base (and perhaps also a set of smooth drawbars) it would be money well spent. The TREK percussion unit, while good sounding, is an absolute dog to use live because of the sliders.
                      Current organs: AV, M-3, A-100
                      Current Leslies: 22H, 122, 770


                      • #14
                        He has a '54 C2, so it will already have smooth drawbars.
                        I'm David. 'Dave' is someone else's name.


                        • enor
                          enor commented
                          Editing a comment
                          Right! Then he'll also have the correct matching transformer. Good!

                      • #15
                        Yes I already have smooth drawbars. I may not mount the switches yet actually . I just want to leave it on and go to the Bb preset for other sounds.For now.

                        So what I am asking is where the C-2 wiring goes into the A028. Besides the AC hookup its something like 7 wires.

                        So I assume everything else relates to the percussion switches.

                        Ultimately I may not want the Trek II. I think resale would be better if I could eventually make it a functional C-3.


                        • enor
                          enor commented
                          Editing a comment
                          "no vib" -> A
                          "vib" -> B
                          "vib line" -> C
                          "scan" -> D
                          "vol soft" -> E, F
                          "GND" -> BN

                          ... and the rest are percussion related:
                          H - busbar to be "percussed"
                          J - return of signal from above to drawbar in question
                          K - percussion trigger signal (busbar #9)
                          L,N,M - all related to the perc decay switch. Connect L to N and leave M open for percussion "decay fast".