Ebay Classic organs

Collapse

Announcement

Collapse
No announcement yet.

Allen's Amplifier vs. Component Placement

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

  • Allen's Amplifier vs. Component Placement

    I've noticed that on Allen organs, going back as far as I can remember, they ALWAYS place the amplifiers in the floor of the organ with the components ABOVE the amplifiers. It seems to me heat is the enemy of electronic and digital components, so it makes me wonder why they are placed above the greatest heat-producing items in the organ.

    Is it a weight issue (because the amplifiers are so heavy)? Is it a balance issue by lowering the center of gravity by putting the amplifiers in the bottom of the organ so it won't be so top-heavy? What do you all say?

    Michael

    P.S. I've noticed the same on other organs as well, including Rodgers instruments.
    Way too many organs to list, but I do have 5 Allens:
    • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
    • Lowrey Heritage (DSO-1)
    • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

  • #2
    Putting the heavist parts at the bottom makes logical sense from the POV of balance.
    -------

    Hammond M-102 #21000.
    Leslie 147 #F7453.
    Hammond S-6 #72421

    Comment


    • #3
      There were several reasons the amplifiers were placed on the floor of the organ. One of them was because of the weight and size of them. Another one is, if the organ has internal speakers, the amplifier can actually cause a an audio hum in the speaker if the amplifier is too close to the speakers. As strange as it may sound it has actually happened. Another reason is it is easier to remove and replace the amplifier when they are sitting on the floor of the organ. There are also a couple of other reasons which I would rather not explain. There are some exceptions though, such as when they are placed on a shelf when multiple amplifiers are in an organ.

      Comment


      • #4
        Thank you, you795a. My 505B, the ADC-6000, ADC-5400, and ADC-4300 all have amplifiers on the floor as well as on a shelf above inside the organ.

        What made me think of this is because I recently saw photos from the custom ADC in GA that was recently parted out (Johnson Ferry?). In my ADC-8000, it has a couple amplifier racks, and all the amplifiers are below the antiphonal relays. In other ADC organs with amplifier racks, there were cages above the amplifiers. If the cage cards are sensitive to heat, it makes me wonder why the amplifiers were put above, rather than below the cages.

        Your explanations partially explains why that arrangement was chosen above other options. Thanks all for weighing in.

        Michael
        Way too many organs to list, but I do have 5 Allens:
        • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
        • Lowrey Heritage (DSO-1)
        • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

        Comment


        • #5
          If or when organ manufacturers start using modern Class D amps, these problems will all disappear, as Class D amps generate no perceptible heat, radiate no hum via transformers, and weigh only ounces instead of 10 to 20 pounds per channel!

          But to be honest, I've not noticed Allen amps generating just a lot of heat in a typical setup. The ventilation provided in most consoles seems sufficient to keep the electronics cool enough for safety. Modern solid state amps are very cool-running compared to the tube-type beasts of the old days that could literally help you heat your apartment in the winter!
          John
          ----------
          *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

          https://www.facebook.com/pages/Birds...97551893588434

          Comment


          • #6
            When I poked my nose into a few MDS Allens, I saw the ADC amplifiers about midway between the floor and the keydesk on little shelves next to the swing-out panel. So it is not universally true that Allen placed them on the floor.

            Comment

            Working...
            X