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Thread: Audio inputs on amp.

  1. #1
    ppp Pianississmo jwl5151's Avatar
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    Audio inputs on amp.

    Hi I replaced two of my S-100 amps with an AM 100 amp. with two channels. Can anyone tell my why there are two sets of inputs.
    There are two on top one RCA and one screw on type. Then there are two RCA plugs under the two on top. I can not figure out what the
    two bottom inputs are for. I understand the top inputs, one is for a screw on cable if that is needed and the other is for an RCA plug.
    Thanks J

  2. #2
    mf Mezzo-Forte Leisesturm's Avatar
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    Quote Originally Posted by jwl5151 View Post
    Hi I replaced two of my S-100 amps with an AM 100 amp. with two channels. Can anyone tell my why there are two sets of inputs.
    There are two on top one RCA and one screw on type. Then there are two RCA plugs under the two on top. I can not figure out what the
    two bottom inputs are for. I understand the top inputs, one is for a screw on cable if that is needed and the other is for an RCA plug.
    Thanks J
    Is this your new amp? Is yours marked as well as this one? Looks to me like each channel has an A and B input. That does not seem strange. The A side can accept either a coax or RCA input. The B side can only accept an RCA input. Next to the B input is an expression input which would control both the A and B inputs of its associated channel. That's how I read it. I can think of four other regular posters who know far more about this stuff than I do so I'm just holding your hand till real help arrives.

  3. #3
    Moderator myorgan's Avatar
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    jwl5151,

    In the photo link provided by Leisesturm, you'll see something similar. Channel 1 is on top, and Channel 2 is on bottom. Channel 1 drives one speaker for certain stops, and Channel 2 drives another speaker for other stops.

    The input is either the RCA OR the Coax (Gerrold?) connector on the top (A Input). In the B input section, the RCA connector on the right is marked, "EXP." That is the RCA jack to use to connect the expression pedals for your organ. Unfortunately, I don't know which vintage organ you purchased (and am too lazy to look right now), so from there, the advice diverges depending on the organ you have.

    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)
    • 9 Pump Organs, 1 Pipe Organ & 4 Pianos

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    ppp Pianississmo jwl5151's Avatar
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    I have an Allen 632-3D

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    Moderator myorgan's Avatar
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    Quote Originally Posted by jwl5151 View Post
    I have an Allen 632-3D
    That is a MOS-1 instrument, and I can't remember if expression on that organ is the same or different than MOS-2. One of them needs expression connected to the RCA jacks I indicated, but the other (I believe) does not.

    In the meantime, there is an article by one of our Allen techs (jbird604) here, which explains the major differences between the codes on Allen amplifiers. The same is true of the AM-100 amplifier. It can be a Code 13 for one organ, while another AM-100 amplifier will be a Code 5 or Code 7. I hope the link helps.

    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)
    • 9 Pump Organs, 1 Pipe Organ & 4 Pianos

  6. #6
    Moderator jbird604's Avatar
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    1 members found this post helpful.
    The AM-100 is more or less a universal amp for all MOS-1 and MOS-2 organs. On MOS-1 or -2 organs, IN GENERAL... if the amplifiers are located inside the console, the expression takes place at the input of the amplifiers. So, those MOS organs require that there be three RCA jacks for each channel. One is for the incoming audio signal (from the DAC board), a second one is for the "mute" function (goes to a sound relay located somewhere else in the organ), and a third one is for the expression pedal connection.

    MOS-1 or -2 organs which have the amplifiers on a remote rack will have the expression components mounted within the console itself, usually under a metal cover in the floor of the console where the coax cables come out that are then routed on to the amp rack. So organs of this type require that the amplifier have only one connector -- a coax screw-on.

    So you can see that this AM-100 covers all the bases. Since your 632 has the amps on a remote rack, the only connection you need on each channel is the coax. So you can ignore all the RCA jacks. The only possible exception is if your 632 has one of the flute channels bi-amped with a little crossover box. In that case, the hi and lo outputs of that crossover box are probably RCA cables, and you would need to connect these to an RCA input.
    John
    ----------
    Church: Allen MDS-45 with Allen MIDI-DIVISION-II expander
    Home: Allen Renaissance R-230 with expanded four-channel audio and MIDI-DIVISION-II
    Shop: Bunch of organs in varying conditions, some good, some not...
    Half of an incredible two-man organ service team -- servicing all the major digitals in Arkansas churches
    https://www.facebook.com/pages/Birds...97551893588434

  7. #7
    Moderator myorgan's Avatar
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    Thank you, John. I knew I could rely on you for an authoritative answer on this question.

    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)
    • 9 Pump Organs, 1 Pipe Organ & 4 Pianos

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