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Allen Gyro Speed

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  • Allen Gyro Speed

    On the Allen T-12 I play, is there any way to increase the speed, therefore, vibrato depth? Or am I not understanding the nature of vibrato?

  • #2
    Depth of vibrato (or even tremolo) is related to the amount of change (pitch or amplitude) that is produced, not the speed at which it cycles. That would be called the speed of the vibrato, or the rate. Speeding up the rate probably has very little effect on the "depth".

    As to whether or not it is possible to alter either the speed or the depth on your instrument, I will have to defer to those more knowledgeable.



    • #3
      The modern way to get deep, "theatre" vibrato is to insert a digital effects box between the preamps and the power amps. Allen used non-standard voltage between the two on at least the MOS models, so doing this requires some additional engineering on those models. I have a Digitec quad 4 effects box with 400 digital effects; My digitec is 20 years old and needs power supply capacitors. They are now bankrupt, I got mine used. I think Peavey still makes one in Mississippi and there are other brands of oriental origin. These multi effect boxes have two channels, and can produce vibrato of opposite phase on the two channels for a simulation of a rotary speaker. The standard effects box or guitar pedal (single effect with a foot switch) has 1.6 VAC in and out interface, with about 1000 ohms drive coming out. A preamp level signal. I don't think a guitar pedal version will have that deep a vibrato. I would check at the store for a deep theatre vibrato, as this sound is not that popular these days except among theatre organ enthusiasts. You can possibly audition a Peavey effect at a Peavey retailer.

      The heaviest way to get deep theatre vibrato is a Wurlitzer spectratone unit, which swings the speaker wider than your gyro probably. These came out in about 1963. These are a steel box about 18" x 18" x 8" and are for sale separately in a wood box, or come in 4300 or 4500 organs. You can listen to the 4500 on youtube, if that doesn't find it search for paulj0557.
      I paid $45 for my 4500 dead, and $30 for my 4300 also dead. Each spectrasonic needs a new rubber belt and rubber mount feet. The parts are probably available from Morelock's organ service of Rienzi, Mississippi who specialize in Wurlitzer parts. You could probably also find this spectratone speaker box on e-bay. The spectratone is a speaker level signal and would hook up exactly as your gyro speaker does. They sometimes need a new mercury coupling on the speaker shaft, which is also available from Morelock's.

      The first component size breakthrough in deep theatre vibrato effect (1967) was the Hammond H100, H200, H300 models. They had a synchronous motor with a rotary capacitor drum. H100's are frequently broken up for parts and these drums and scanner lines (capacitor assemblies) are for sale on E-bay rather cheaply. Sometimes a synchronous motor is included, sometimes separately.. these require about a a 10 VAC drive at about 50 ohms impedance, so some sort of preamp is required. The hammond vib drive preamp board take +24 Vdc and +100 Vdc. The motor is a 120 VAC one in the US and 240 VAC in Europe. The drive is a 3/32" round belt, or O-ring, with various pulley sizes for fast vibrato or slow celeste vibrato (two different drums in the Hammond implementation). The Hammond will do two channel with the left speaker of the opposite phase of the right speaker.

      Good hunting.
      Last edited by indianajo; 01-14-2014, 08:48 AM.
      city Hammond H-182 organ (2 ea),A100,10-82 TC, Wurlitzer 4500, Schober Recital Organ, Steinway 40" console , Sohmer 39" pianos, Ensoniq EPS, ; country Hammond H112


      • #4
        Appreciate the tips. I was sort of hoping there was an easier way but oh well.


        • #5
          Allen's Gyro cabinets rotate the speakers on a single plane, facing the listener. Imagine the speaker cabinet itself spinning and you get the idea. When on SLOW (for the two speed models), it imparts that essential movement to the sound that keeps early electronic organs from sounding so, . . . . electronic. On FAST it makes the light vibrato you're familiar with. That's the way my String sound worked. What might solve your problem very reasonably might be a single speed, single rotor Leslie cabinet. Because they are not particularly suitable for gospel, rock, or jazz, their value is very low. I have one that could be had for just a shade over a hundred with an 11 pin interface. They are probably available all over the country. They can be readily driven with a speaker level signal which means you could just take a signal off your present Allen cabinet. That's particularly good, if you want to retain your present control. My single speed Allen gyro handled the flutes and turning OFF the vibrato routed the signal to the non-gyro cabinet - - the gyro ran constantly. This would easily adapt to a Leslie that would also run constantly.

          Add a location to your profile and someone in your area may have some help to offer.
          Roland Atelier AT-90s, AT-80s, AT-70, 30, and 15. Roland VR-760 combo
          Yamaha S-90, Kurzweil PC-3x, Casio Privia PX-330, Roland E-80, G-70, BK-5, Leslie 760, 820
          Moved on:
          Allen 3MT/Hauptwerk, Technics GA1, Yamaha HX1, AR80, numerous Hammonds, including 2 M's, an L, 2 A-100's, XP-2, XM-1/1c, & an XK-3. Roland Atelier AT-30, 60r, 80, & 20r(2 units), and a slew of Leslies (147, 142, 760, 900, 330).
          Korg Triton Le-61, Casio Privia PX-310 & 110, and Kurzweils: PC-2x, SP-88, Pro-III, K1000