WURLITZER 4600 Series Instruments

North Suburban HAMMOND ORGAN Society

Here we'll take somewhat of a "tour" through the Wurlitzer 4600 series instrument. These pictures will give you a good idea of what the electrostatic reed tone generating system looks like and how it is soundproofed so that its normal operating noise does not intrude on the music.

One thing that should be evident from looking at these and the following pictures is that a great deal of careful thought went into the construction of these instruments, and also the workmanship is excellent. Many of the more modern electronic organs used foil-covered cardboard boxes as shielding around sensitive circuits. True, this does work, but it really looks cheap, and it is cheap. Would it really have been such a big deal for those outfits who did this to use sheet metal instead, Evidently those companies thought so! I don't know, but somehow a Wurlitzer reed unit with foil coated carboard boxes over the reeds would just not make the grade in my estimation. Of course there was a slight air pressure differential and cardboard boxes would have leaked.

general look inside the console

Figure 5. Here is a look inside the console; what you see when you remove the back cover. As you can see, it looks pretty much like many other 1950s electronic organs with an amplifier/power-supply chassis at the bottom, and above that, a 12" coax speaker. To the right, you can see part of the reed unit's soundproof enclosure.

The reed unit with compressor on the top.

Figure 6. With the outside cover, the one inch felt and the inside Masonite covers removed we get a look at the actual reed unit which also shows the centrifugal compressor on the top, and the drive shaft and coupling extending out through the left side to the motor. Three of the seven reed pans are visible as is a part of another pan on the right end of the unit. Three more pans are on the other side of the reed unit. The entire housing can be removed from the console for access to all of the reed pans. Notice the substantial construction of the reed unit outer enclosure. The Wurlitzer people sure didn't want any reed noise to be audible. Keep in mind that all 85 reeds are vibrating continuously whenever the instrument is powered on!

Centrifugal compressor motor close-up

Figure 7.This closeup shows the motor for the centrifugal compressor. In a sense, these 4600 series instruments are a little like the Hammonds, in that they use electro-mechanical means for tone generation, although the principles involved are entirely different.

 

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