Hammond S6 Chord Organ to Fender 5F11 Tremolux

Discussion in 'Shock Brother's DIY Amps' started by ArcticWhite, May 15, 2021.

  1. ArcticWhite

    ArcticWhite Tele-Afflicted

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    Just picked up this free Hammond Chord organ off Craigslist.
    Planning a 5F11 Tremolux build, using as much of the organ as possible.

    One pair of Rola 16 ohm speakers, plywood baffle, grille cloth and the OT.
    Pair of 6L6GC, 5U4GB, and 12AX7s.
    Lots of resistors and tube sockets.

    The PT is physically large, because it powered about 30 tubes, but THE Hammond schematic shows a B+ of just 295 volts.

    Would it be possible to use this OT, or will the voltages go up too much when it's only powering 5 tubes? The 5F11 B+ is 340 volts.

    20210515_150050.jpg

    20210515_135336.jpg 20210515_135329.jpg 20210515_135319.jpg 20210515_135154.jpg HammondS6psu.png

    Also, the organ has an extra pair of transformers in the solo circuit. Are these both OTs with the labeled "Input Transformer" simply an OT running backward?

    _thumb_HammondS6soloVCA.jpg
     

    Attached Files:

    Last edited: May 15, 2021
  2. Nickfl

    Nickfl Friend of Leo's

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    I bet it would be ok, but it would help to know what the unloaded voltage is.
     
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  3. printer2

    printer2 Poster Extraordinaire

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    Aww, that is so wittle. Surprised it has a pair of 6L6's. The lack of load on the transformer will not have much of a issue on the plates, the tubes have been known to take a fair amount more. The heater voltage would be the one to watch. The solo transformer is used as the phase inverter. Do you have a full schematic? I am wondering what tube they have driving the transformer.

    No idea where I got 6L6 from, a pair of 6V6's. Still going through the service manual.
     
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  4. ArcticWhite

    ArcticWhite Tele-Afflicted

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    The schematic file is a GIF, and it won't upload to the thread for some reason.
    Here's a link to it.
    https://web.archive.org/web/2006050...n.com/clonk/ChordOrgan/Schematics/Figure6.gif

    If you can post it somehow, that would be cool.
     
  5. ArcticWhite

    ArcticWhite Tele-Afflicted

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    What's the sonic effect of having an overly large power transformer, assuming the voltages work out?
     
  6. printer2

    printer2 Poster Extraordinaire

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    The solo circuit looks to be something along the lines of old compressors They used a pair of 6BA6 tubes, variable gain pentodes that are usually used in radio front ends to compensate for weaker and stronger radio signals.

    Hammond S-6

    http://crasno.ca/articles/HammondS6.htm

    Service manual

    https://archive.org/details/HammondChordOrganServiceManualModelsSS-1S-4


    30 vacuum tubes in total:
    • Generator Chassis:
      • 2x 6BA6 pentode
      • 1x 6BJ7 triple diode
      • 1x 6C4 triode
      • 2x 6V6 beam tetrode
      • 10x 12AU7 dual triode
      • 2x 12AX7 dual triode
      • 3x 12BH7 dual triode
    • Organ Chassis:
      • 8x 12AU7 dual triode
    • Power Pack:
      • 1x 5U4GT dual diode / full-wave rectifier
     
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  7. printer2

    printer2 Poster Extraordinaire

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    A sore back. Thanks for the schematic, much easier.

    The tube complement on the service manual I was looking at had octals where you have miniature tube. You have a life supply of 12AU7's. Save the solo transformers and tubes when you want to make an old school compressor.
     
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  8. ArcticWhite

    ArcticWhite Tele-Afflicted

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    Thanks for the research!
    Ha! I already have hundreds of 12AU7s from previous organ pulls. I'm thinking of handing them out at Halloween.

    Yeah, I'm give this honking big PT some serious side eye. The 2x10 issue is already making this thing heavy. I don't want to build a boat anchor.

    Wondering about using just one of these 16 ohm speakers. The OT has a center tap on the secondary. Is that one perhaps usable as a 16 ohm output?
     
  9. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    +1 on measuring the unloaded B+ before you make any decisions. I bet the PT has plenty of current capacity for a 2x6L6 guitar amp, although the OT is probably only good for 12 watts at best.

    (I have guts from a Hammond S6 lying around, too. Haven't gotten around to building anything with them yet. :D)
     
  10. printer2

    printer2 Poster Extraordinaire

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    The centertap does not help you, it would if you had a four ohm speaker. At least they do not have massive ceramic magnets. And here I am with all kinds of power transformers I won't be using. Well, maybe one or two.

    [​IMG]
     
  11. pinchegil

    pinchegil Tele-Meister Platinum Supporter

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    Heater voltages will be way off. Look up the currents of all of the tubes minus rectifier. Figure out total amps , then calculate amp requirement for what you want to build and calculate how much resistance you will need to add. 30 tubes? Think really really big resistors, (power wise) and we haven’t even talked about what voltage it’s rated at.
     
  12. archetype

    archetype Fiend of Leo's

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    The Unasked For Opinion: Don't kill another organ. Play it. That thing should be an easy and fun addition to anything you want to record at home.
     
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  13. AlbertaGriff

    AlbertaGriff Tele-Afflicted

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    OP tell me about your shoes please?
     
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  14. bebopbrain

    bebopbrain TDPRI Member

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    "Would it be possible to use this OT, or will the voltages go up too much?"

    I think you mean PT. The PT is 285-0-285, which seems ideal. I would use the power supply exactly as built. Keep R90 and the 5U4 diode. Replace the 30uF/450VDC first cap with something similar. Don't use a huge first cap. Later caps can be huge.

    The schematic shows B+ at 295VDC but you will get more because today's voltages are higher and there will be less of a load on the transformer. But you won't get won't get voltages that are scary for 6V6s or 450VDC caps. B+ should be close to 340VDC. I wouldn't worry about B+ being off by 5% or 10%. But there are lots of things I don't worry about.

    If you go with a 5Y3, B+ will be lower. With solid state diodes B+ can be higher. I recommend starting with the exact unmodified Hammond power supply and that should work out great.
     
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  15. ArcticWhite

    ArcticWhite Tele-Afflicted

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    One of my many pairs of fly ass skate shoes, these are "Chinos" by Supra. They're a few years old though so probably discontinued. Looks like some odd sizes available on different colors here and there on Ebay and Amazon.
     
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  16. SerpentRuss

    SerpentRuss TDPRI Member Ad Free Member

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    Quite a find, I think. It will be interesting to see what you can make from it.
     
  17. printer2

    printer2 Poster Extraordinaire

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    I would think he would put resistance in series with the tubes being used. Measure the voltage drop required after the amp is up and running, calculate the resistance needed, divide that in half and put a resistor inline on either side of the heater string to keep the voltage split evenly across the tubes. Then either a pair 100 ohm resistor or pot to go to ground, or use an elevated voltage.
     
  18. jmp81sc

    jmp81sc Tele-Meister

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    I have built two amps using S6 guts. I did build threads on them. A 5E3 and an 6G4A Super but with 6V6 power tubes. I think my B+ was about 350 volts. The OT is kind of small but seems fine in my builds. No issue with heater voltages. My speakers were 8 ohm Rola alnicos. I used the lower power supply as is with and updated power cord and I put a fuse by the PT. I kept the power supply in the bottom and ran longer wires up to the chassis. I did not use the Hammond power supply filtering and grounding, I grounded the B- center tap to the main ground.

    I salvage the center part of the organ case and reused the 2 x 10" baffle. I kind of prefer 2 10's over a single 12 so that worked for me. I also used part the upper "chassis" and kept the power tubes and OT in the original position. I stripped out all of the wiring etc, but I left the 9 pin sockets in place and used them for the tube compliment I built. I also stripped and reused the terminal strips and boards.

    The OT has a center tap on the secondaries that is grounded in the organ, but you need to lift that to make it work for guitar, otherwise it is very low volume.

    I did feel a little bad stripping them, but both of the ones I got were non working and beat to crap. It will be pretty heavy and big if you do what I did.

    Take Care
    John
     
  19. RollingBender

    RollingBender Tele-Afflicted

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    I have acquired probably close to two dozen old organs over the years...all for free. The reason they are free is because nobody wants them. If there was some value in saving them as organs, there would be folks out there snatching them up. This may change sometime in the future but it has not happened yet.

    Of those two dozen, I chopped one Hammond M3 to look like a Baby-B and sold a nice A100 to an organ jockey for a few hundred. The rest became organ donors.

    Build away and feel no guilt.
     
  20. archetype

    archetype Fiend of Leo's

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    I get it and you're right. This chord organ is just so cute, though. It would be like parting out a baby. :rolleyes:
     
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