JMI Vox Echo-Reverberation Unit - "Cliff Richard Reverb" (1962 - 1968)


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The Vox Echo Reverberation unit was introduced in the 1962 Vox catalog. Vox featured Cliff Richards in early print ads for the device, earning it the name the "Cliff Richards Reverb."

The Development of Electronically Simulated Reverb at the Hammond Organ Company
As the popularity of the electronic organ surged in the 1950s, the Hammond Organ Company desired to develop a means to simulate the lush, reverberant sound of an auditorium in their home organs. The engineers at Hammond Organ developed a electro-mechanical device called a "delay line" that recreated this concert hall effect in the living room.

In simple terms, this first generation Hammond delay line was comprised of a electro-magnetic audio "transducer" and an electro-magnetic audio "pickup" interconnected by a four foot long transmission spring. The transducer converted a portion of the organ's audio signal into vibrations that were introduced into one end of the transmission spring. The sound was delayed and reflected within the transmission spring as it traveled from the transducer to the pickup. The pickup converted the vibrations from the transmission spring back into an audio signal. When the delayed, or "wet" audio signal from the transmission spring was blended with the original, or "dry" audio signal of the organ, a simulated reverb effect was created. Hammond installed this first generation delay line into the refrigerator sized powered speaker (or "Tone") cabinets that accompanied their organs.

Fender Licenses the Hammond Reverb Design
This first Hammond delay line was too large to use in portable devices. The creative engineers at Hammond Organ continued to refine their electro-mechanical reverb design, culminating in 1960 with the introduction of the dual spring "Type 4" reverb pan. The Type 4 not only improved the tone and delay of the earlier Hammond designs, it reduced the four foot length of the original design to less than 18." Hammond patented the Type 4 reverb pan design and installed it in their organs. They also offered it, under license, to other manufacturers seeking to add reverb to their audio devices. One of the earlest adopters was Leo Fender. His 6G15 Fender Reverb Unit, introduced in 1961, was a stand alone device that would add reverb to any guitar amplifier. Eventually the Hammond Type 4 reverb design would be included in numerous amplifiers from Fender and others.


6G15 Fender Reverb


The Vox Echo Reverberation
The "Vox Echo Reverberation" was the JMI response to the Fender Reverb Unit. The four tube circuit design for the Vox Echo-Reverb was detailed on JMI schematic #A62/005 dated January 30, 1962. A revised schematic (#OS/011) was produced in September 1964. The Vox Echo-Reverb first appeared in the 1962 Vox catalog and was last offered in the 1968 Vox Sound Equipment Limited catalog .

Unlike the single channel Fender Reverb Unit, the Vox Echo-Reverb featured a dual channel design with independent volume controls for each input.

The cabinet for the Vox Echo-Reverb was the size of a typical guitar head. The front panel of the Vox Echo-Reverb cabinet was designed to match the "split face" cosmetics of Vox combo amplifiers.

The earliest Vox Echo-Reverb cabinets were covered in fawn vinyl. A transition from fawn to smooth black vinyl occurred in 1963. By early 1964 the smooth black covering was replaced with black basket weave vinyl. This vinyl was used through the end of production. While many Vox Echo Reverb units had brown Vox grill cloth, black Vox grill was also used in later production.

Earlier units featured brass vents, copper control panels and swivel luggage style handles. By 1965 black plastic air vents, gray control panels and Vox logo strap handles were the norm.

Some Vox Echo-Reverb units had a "VOX Echo" badge in the corner of the grill (see above). This badge was a bit misleading as this unit produced only reverb, not echo.

The Vox Echo Reverb was also produced in 1963 and 1964 with a "Cliff Richards Reverb" name plate in place of the "Vox Echo" badge shown above. Cliff Richards was also involved in print ads for the Vox Echo Reverberation.


Bypassing the Hammond Patents
While the 6G15 Fender Reverb and the Vox Echo-Reverberation both included a dual spring delay line, the Vox Echo-Reverberation did not utilize the Hammond Type 4 reverb pan. JMI designed their own delay line that narrowly bypassed Hammond's patents. For their reverb pans, JMI replaced the electro-magnetic transducers and pickups of the Hammond Type 4 design with inexpensive and somewhat fragile ACOS brand crystal phono cartridges (see photo at left).

In his 1991 book, "The Vox Story," lead JMI engineer Dick Denney indicated why Vox chose to not include the Hammond Type 4 reverb pan in their products. Denney explained that Vox was unwilling to pay a license fee to Hammond Organ for the use of their patented delay line.








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Photos and editorial content courtesy Gary Hahlbeck, North Coast Music


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