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1964 Mylar capacitor history detail

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  • 1964 Mylar capacitor history detail

    I've run across a 1964 Hammond tone generator on which the vast majority of the tone generator capacitors are the last generation of paper capacitors mixed with a very few red Mylar capacitors. The Mylar caps have a 6414 date code, putting them in the last week of March 1964. There are only two 0.105uF red caps on the first row of the generator filters, so it may be that this was the first shipment of Mylar film capacitors that Hammond used. The reverb tank has a 6415 date code, so depending on how long it took for these parts to make it into an organ, maybe late April/May 1964 is when the Mylar red cap transition occurred. But it was not a sharp transition. They seem to have continued to use paper capacitors until they ran out, at which point they started grabbing the new ones.

    This organ also has one felt (lower) and one foam (upper) manual.
    I'm David. 'Dave' is someone else's name.

  • #2
    Could be. Sure, why not?

    But it strikes me as a more likely scene where the organ has been gotten into and messed with - perhaps several times - by various people.

    In a production atmosphere, where they would have multiple benches soldering caps into place, the idea that they oozed into a new device seems unlikely. "Exhaust Current Stock" is certainly common in factory paperwork, but a component shift mid-product? Seems unlikely, but hey, who knows? Someone reaching into the same bin they always reach into and pull out different caps and just go with it?

    After all, the TWG would later get voiced and what did it matter?

    And one foam manual? Again, was that the day and the organ that they made the change? I'm guessing not, but guessing that sometime in the last 55 years of use, someone sold them on a manual replacement. I mean, in 1982 - when the organ was 'really old' and 'worthless' - I could buy pull-off console manuals for what? $50? And if someone had broke a bunch of keys from abuse, the tech coulda spent big time and money on individual replacement or just sold them a new manual. I mean, that's my guess, but I know stranger things have happened.

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    • #3
      Do both kinds of caps have Hammond part numbers? If what I read is true, where incoming new capacitors were sorted and graded according to their value, then put into bins, I can see how there would be a mix used on more than one tg until all the old ones were eventually used up.
      Tom in Tulsa

      Fooling with: 1969 E100, 1955 M3, 1963 M100, Leslie 720

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      • #4
        Originally posted by tiredoldgeezer View Post
        In a production atmosphere, where they would have multiple benches soldering caps into place, the idea that they oozed into a new device seems unlikely. "Exhaust Current Stock" is certainly common in factory paperwork, but a component shift mid-product? Seems unlikely, but hey, who knows? Someone reaching into the same bin they always reach into and pull out different caps and just go with it?
        I've been working on Hammonds for 29 years, and it's not really unlikely at all. The earliest AO28s were built with leftover 0.25uF capacitors from AO10 production until they were presumably all used up. The schematic says 0.33uF, but that's not what's in them. And other techs have seen tone generators with a mix of paper and Mylar caps, including Sal Azzarelli with whom I discussed this years ago, so it's not that unusual. Mixes of felt/foam manuals have also been documented in other Hammonds from the transition period in late '63 and early '64.

        In a 1949 CV generator, I found 0.105uF paper capacitors from three different capacitor manufacturers (CDE, E.U.C, and John E. Fast) on one tone generator, so there is precedent.

        And what about all the CVs Hammond built in cabinets with holes for chorus generator and a blank metal piece screwed in place where the chorus generator drawbar would have been?

        Similar things have been documented across many music brands like Fender. They'd use up stock of one chassis, cabinet, or transformer before switching to the new supplier. They were in the business of building products and getting them out the door to make money; they didn't care if the type of capacitor used was perfectly consistent. Who would care? It's simply of historic interest to those of us who notice and document these things.

        I'm David. 'Dave' is someone else's name.

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        • #5
          This A100 is coded 6347,6348,and has one manual felt and one foam.Lots of 'one each' left that plant.Last of the cardboard tube type paper TWG filter caps that late '63 early '64 period.
          If it sounds even in tone and balance,I won't mess with them.
          Earlier A100,a '60,has replacement mylars,it wasn't my call......still the organ sounds great.
          This '62 A102 has both manuals felt.Cardboard tube caps too.....I hung a '70 AO28 off it and it brightened right up!
          David and Geo and many others have told us for years to rebuild the preamp first,great advice!
          There are occasions where a TWG filter re-cap is a definite improvement.
          AO28 with a refresh can change your mind about changing the TWG caps though....

          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!

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          • #6
            This organ sounds great. This post is not about recapping at all. Somewhat ironically, the last generation of paper capacitors that Hammond used seems to be holding up very well. It's like they finally got it right just in time for the technology to be replaced. I have a Franken-organ with a '63 generator, and it sounds fine. Doesn't need recapping in the slightest.
            I'm David. 'Dave' is someone else's name.

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            • #7
              Originally posted by David Anderson View Post

              I've been working on Hammonds for 29 years, and it's not really unlikely at all. The earliest AO28s were built with leftover 0.25uF capacitors from AO10 production until they were presumably all used up. The schematic says 0.33uF, but that's not what's in them. And other techs have seen tone generators with a mix of paper and Mylar caps, including Sal Azzarelli with whom I discussed this years ago, so it's not that unusual. Mixes of felt/foam manuals have also been documented in other Hammonds from the transition period in late '63 and early '64.
              Dude, like i said, I don't know for sure. If you wanna believe that's the case, you do you.

              If you've been working on Hammonds for a whole 29 years, then that means this Hammond saw 26 years of who-knows-what before you started.

              Rumors are rumors. Maybe they're true. Legends grow from rumors and always have a kernel of truth. Sure, if it's Hammond folklore, why not?

              It's interesting from several different perspectives.

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              • #8
                Sigh . . . This forum is definitely not what it used to be.

                There are those of us who've been paying attention to lots of little details of Hammond construction for many years, and we can usually tell by various clues if something has been messed with or swapped out. The mixes I'm talking about are found ONLY in organs from the period of late '63 to mid '64.

                For example, I do know that someone, at some point, swapped an older Pedal Solo Unit into this organ because I know what to look for. But all the rest of it matches the period in question, including things like dates on the bass pedal inductor cover on the upper manual, capacitor date codes, speaker date codes, etc... If things looked suspicious in this organ, I wouldn't have posted about it.

                I'm David. 'Dave' is someone else's name.

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                • #9
                  Originally posted by David Anderson View Post
                  Sigh . . . This forum is definitely not what it used to be.
                  You're right.
                  It used to be HamTech.

                  Comment


                  • #10
                    Notice the moderators of this Forum's countries of origin?......and the location of Hamtech?
                    Unlikely we will "Make Organ Forum Great Again"......and get stuck with a thousand unwanted hats.
                    I have made some good friends here,and on Hamtech. Still,this is a great Forum IMO.
                    There are lots of leftover parts used up in many things built besides the Hammonds of a half century ago.

                    I have an early Nord Stage3 HA88,from way back in 2018. A newer user interface is already on the 2019's.
                    Unlike Hammond consoles,these things change very fast.Want to bet there are 'early 2017 parts' in this one too?

                    I do have some USA built Switchcraft connectors on my rigs,everything else besides the old Hammonds/Leslies?
                    is from somewhere else.....




                    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!

                    Comment


                    • #11
                      This ebony A-101 serial 24024 has all wax caps on the tg and both manuals are felt. Reverb date code is 4962 ,so Dec 1962. The organ went out in 1963 before the cap and felt changes.

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                      • #12
                        I do have a correction to make since I've been trying to do too many things at once these last few days.

                        Looking again, I realized that the red/Mylar capacitors on this tone generator are all the 0.25uF value, which fits with what Sal Azzarelli wrote me years ago -- that Hammond first started using Mylar caps on tones 49-54 while still using paper on 55-91. The dates on the General Instrument paper caps on this TG and the Mylar caps are both 64-14.

                        In fact, what's eerie here is that when Sal and I discussed this topic prior to his death, he wrote to me on May 26, 2015:

                        "The earliest example I've seen with mixed caps is an A105 with a generator build date of 7/15/64. . . . I'll bet the organ sn is right around 40000 and the stamp is 1D7GT.”

                        (Sal had documentation showing the build dates of the generators based on their date stamp in the lower corner.)

                        The date stamp on the TG of the D-152 I just acquired is 1D7GT. I did a double-take when I re-read Sal's note.

                        I'm David. 'Dave' is someone else's name.

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                        • #13
                          David, I wonder if you can answer this question about the behaviour of aged wax caps. When we talk about wax capacitor values changing with age, does the change in value/quality continue to deteriorate for ever or do they stabilise? My 1937 BC with original caps sounds pretty bright to me and I am happy with the character. Will this gradually deteriorate further? Hope this makes sense!
                          Hammond C3, M102, XB3, XB5, X5
                          Lowrey Heritage DSO-1, H25-3, Yamaha E70
                          Farfisa Compact Duo Mk2, Vox Continental 300, Korg BX3 Mk1, Leslie 122, 145, 910, 415
                          www.drawbardave.co.uk

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                          • #14
                            As far as I know, the mechanism of the value change (higher) of the wax-dipped paper capacitors is ambient moisture infiltration into the capacitor because wax-dipping was never the greatest way of sealing a capacitor. We don't often think about it in these terms, but water has a very high dielectric constant, around 80, if memory serves, compared to around 4 for paper in oil. If water gets into the paper dielectric, the capacitance goes up.

                            All I can say is that this process seems to be unpredictable. Some periods of production or even some batches of capacitors seem to have fared better than others. My '59 C-3 is still fine, but I know of two 1952-3 organs that need recapping. And I've serviced some CVs that still sound good, but some of those had the electric heating elements installed that Hammond used to drive moisture from the cabinet.

                            I've never measured capacitors from a 1930s organ, so it is entirely possible that they were better encapsulated than some later capacitors Hammond purchased. Encapsulation/sealing of the capacitors was the key. Note that Hammond used premium paper capacitors sealed in metal (and later some kind of plastic) cases in their preamps. I have yet to see one of the paper capacitors sealed in brown plastic fail.

                            And in the UK, you are in the land of dampness. Did your BC have a case heater installed?
                            I'm David. 'Dave' is someone else's name.

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                            • #15
                              Both of my '64 Hammond A105's have 1 foam and 1 felt keyboard. One A105 has the orangish ( paper/cardboard) twg caps and the the other A105 red mylar......I know the history on both these organs and no one has messed with them.


                              BTW David, Great post! I like these investigative type unfoldings

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