MOS-2 ALLEN , VIBRATO without Function

[praestant]

Hello, my ALLEN MOS-2 organ has a VIBRATO switch. But when i turn on the Vibrato, it has no function. Is the Vibrato couplet with the Tremulant? And how does "Chorus"? This switch is also available on my organ. Thanks.

[myorgan]

Hello, my ALLEN MOS-2 organ has a VIBRATO switch. But when i turn on the Vibrato, it has no function. Is the Vibrato couplet with the Tremulant? And how does "Chorus"? This switch is also available on my organ. Thanks.

Praestant,

Vibrato, Tremulant, and Chorus all have separate duties on an Allen organ:

• Tremulant-Basically, a change in volume (soft/loud), which slightly affects the pitch as well. Think of an Oboe or Flute orchestral instrument playing with a slight waviness to the sound.
• Vibrato-This is more like a theatre tremulant, and involves quite a wide pitch variation. Terms used when describing it on an Allen are when the AM and FM modulations are changed in depth. Too much, and it is unmusical, not enough, and it is more like a Tremulant. On ADC organs, Trem-III devices were employed to effect the Vibrato. I'm not sure on your MOS-2 if it was accomplished with Trem units or TGU devices.
• Chorus-This effect is often used for Reeds, so instead of sounding like 1, 2, or 3 reeds, it will sound like a whole Chorus of them, perhaps slightly out of tune with each other to give the effect.

Hopefully, this brief, clumsy explanation will help.

Michael

[praestant]

Thank you Michael, i think there is a device missing to work the vibrato. In the console are at the motherboard 2 cred able jacks with Flute and Main label , but without (TGU?) device.

[myorgan]

That may be. However, your post just reminded me that John (jbird604) started a thread one time where he found a means of increasing or decreasing the Vibrato on a MOS-2 organ. I will try to find the thread.

Michael