What to build from a hammond organ?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by sidehatch, Apr 25, 2016.

  1. sidehatch

    sidehatch Member

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    What would be an easy project from a hammond? Its an M-AO-43-I. I have the head that has 2 EL84's, and 3 12ax7's and maybe a 12bh7 but I'd need to go look at it on that one. I can post pics if that would be of help.
    Thanks
     
    Last edited: Apr 26, 2016
  2. UsableThought

    UsableThought Supporting Member

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  3. tresspassor

    tresspassor Member

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    It depends mostly on the tube set and transformers that are currently in it.
     
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  4. TimmyP

    TimmyP Member

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    Before you tear it apart, make sure it's not a model that one would want to keep together and sell.
     
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  5. zenas

    zenas Member

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    Besides the B3 what other Hammond doesn't end up out on the curb sooner ot later ? Sad but it's a real small market for organs.
    I spend a little time on organ forums looking for info when I see one for sale or free. Those people know they can get them cheap or free too.

    But yeah a Hammond is worth checking out.
     
  6. RussB

    RussB low rent hobbyist Silver Supporting Member

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    There are many different Hammonds. The one I salvaged had 2 6L6GC's, a 5U4GB rectifier and about 20+ 12AU7's and 10 or so 12AX7's. One of the 4 "transformers" was a filament tranny, so that makes things a bit more complicated. I really liked the wire that was used in it, and built a Marshall 1987 clone with the wire!
     
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  7. sidehatch

    sidehatch Member

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    Thanks for all the replies!

    Its a m-ao-43-I . A friend bought for $20 at a thrift shop because it had 2 12" speakers , 2 el84's , some 12ax7s etc.

    So I got the head with all the iron and dozens of circuit boards loaded with caps and resistors. All I had to do was pull the speakers & tubes for him and give hims some basic caps.

    I'd like to build an easy 15 watt El84 amp. A volume , and tone would really be all thats needed unless I could put a treble-bass setup or treb-mid-bass.

    It does have a choke and reverb tank so if reverb is do-able that would be cool.

    More than anything I would like to learn as I do it while not getting too over my head. I'll look at the links you guys posted and if you have any ideas please let me know.

    Thanks all!
    Shane
     
  8. sidehatch

    sidehatch Member

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    What about something similar to my 1962 gibson falcon but instead of 6v6's use El84's?
     
  9. Don A

    Don A Silver Supporting Member

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    I have a Hammond L100 which has a similar tube line up. I can't give the thing away! I've been thinking about building an 18 watt Marshall clone and wonder if some of the organ's components can be used.
     
  10. tresspassor

    tresspassor Member

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    If you want to keep it simple then I'd suggest a Matchless Spitfire or some variant of a Marshall 18W.
     
  11. TimmyP

    TimmyP Member

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    I'm familiar mainly with the big stuff (A series, A10x series, B series). Some of the smaller M and L are also offer a decent rendition of the "Hammond Sound".

    I don't think any of the preamps are of use (save for tubes and transformers), but any of the tube amps would be useful. The AO35 (reverb amp from the A10x) is useful chassis and all, as this amp is what the original Dr. Z Carmen Ghias were made from (oddly, this amp has larger transformers than the main amp from that organ).
     
  12. kevmin

    kevmin Supporting Member

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    If you have three preamp tubes, I would build a Matchless Lightning.
     
  13. swiveltung

    swiveltung Member

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    Watch the output impedance, it's weird on some of those amps. I have a little reverb amp that uses two EL84's, has the rca jacks for the reverb tank etc. Is that what you have?
     
  14. KramerPacerCarreraGuy

    KramerPacerCarreraGuy Member

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    are there any amp gurus who can do the conversion? I have an AO35 and an AO44. There is a basic conversion that just gets it to be usable for guitar. How does that sound? I'm sure a total rewire/rebuild would sound better, but how much better. It is the cost/time/effort question of is it worth it.
     
  15. tresspassor

    tresspassor Member

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    Mark Moser of Frugal Amps does a lot of these conversions. You might want to contact him.
     
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  16. TimmyP

    TimmyP Member

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    The AO35 sounds pretty darned good with very few changes (change the input section so the impedance is appropriate for guitar, add a volume control if desired, experiment with the negative feedback resistor (including open), and add some grid stoppers to the EL84s just in case. I'll get around to tweaking and finishing the thing one of these days.
     
  17. sidehatch

    sidehatch Member

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    This is my thought . Do you have a reference for a starting point?
     
  18. zenas

    zenas Member

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    I think there's some websites for Hammond conversations. They can get a little tricky because they used so many different circuits. Also sometimes the voltages are way off in organ PTs so that can add to the complexity of a build just getting that in check. (like filiment voltage)

    I tend to be lazy and just use parts out of the curbside organs I get and order new transformers for builds.
    I've got a few laying around I may use some day though.
     
  19. Winnie Thomas

    Winnie Thomas Member

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    Your Hammond was an L100 series. i got one for free locally. The transformers are exceptionally good. The OT is 8K into 8 Ohms, the speakers are a pair of 16 ohm wired in parallel, they are not very toneful or efficient unfortunately.
     
  20. PushedGlass

    PushedGlass Member

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    The L-100 was Keith Emerson's main axe in the Nice and remained in his rig all the way up through the Brain Salad Surgery tour. I don't know my Hammond models encyclopedically but basically any tube-and-tonewheel Hammond that has been maintained in or restored to good playing condition is valuable, although less so if it's a model that does not have key percussion or a way to connect a Leslie.

    As an aside, there are a few models of Lowry organ that will nail "Baba O'Reily" and in conjunction with a VCS3 synth will take you directly to "Won't Get Fooled Again."
     
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