Hammond Solovox Tone Cabinet (1948)

When I saw this mysterious item at a thrift store, I was immediately intrigued. The brass plate on the back declared it to be a Hammond Tone Cabinet. Now, Hammond was a big manufacturer of tube-powered organs, but if this is a musical instrument of some kind, where's the keyboard?

If you have ever peeked inside a tube-powered organ, you know that it always has many more tubes than the thirteen visible in the back of this device. With so few tubes, what kind of music could this critter make—if it generates music at all? Thinking about it for a moment, I decided that the tubes alone were worth more than the asking price, so, partly out of curiosity and partly to save it from a worse fate, I handed over the cash and hauled it home.

The mystery was quickly solved when I posted a query to the rec.audio.tubes newsgroup on USENET. This reply came from Thomas Lehman:

>In article <01bc9a47$c4dffb60$7d802bd1@philnlap>, 
> says...
>One of these followed me home, and now I'm curious.
> This is a knee-high wooden cabinet, very shallow, with
>13 tubes and a decent-sized speaker inside, and a big 
>flat sixteen-pin connector on the end of a cloth-covered cable.
>The cabinet has a flat back and rounded edges -- perhaps 
>it was meant to stand against one end of an organ. A brass 
>plate identifies it as a Model L tone cabinet, to be used with 
>a Model A keyboard.
>
>Anybody familiar with this mystery device?

This is a Hammond Solovox cabinet. The part you are
missing is the little keyboard that attached to the front of
your regular piano keys. It allowed you to play single note
organ solos while you played the piano. The keyboard had
voice controls and a leg operated volume lever.

An example of the sound would be found in the song "Runaway"
by Del Shannon. Think of the solo in the middle played on a 
shrill organ. That is a Solovox.

My later research revealed that the "Runaway" reference is an urban legend. That solo was played by Max Crook on a Musitron, which was a heavily modified Clavioline.

(Another common misconception about monophonic electronic instruments is that the Beach Boys used a Theremin in their song, "Good Vibrations." That solo was actually played on a hand-made instrument nicknamed the Electro-Theremin by its creator, Paul Tanner.)

One recording artist who certainly did use the Solovox is Frankie Yankovic. If you search on Google for "Frankie Yankovic Solovox" you will find a variety of references.

In any case, without a keyboard, the Solovox can't make any music. I owned this cabinet for about two years before I found someone with a keyboard for sale. The seller actually had a complete unit, but wanted to use his tone cabinet for another purpose. After we made a deal for the keyboard alone, he decided not to use his tone cabinet, and offered it to me for an additional $15.

I didn't particularly want two cabinets, but I decided to get the whole unit, since his cabinet was known to work. This is the one that I restored. I later sold the first cabinet to another collector who had nothing but a keyboard.

Restoration Notes

Restoring the Solovox was not difficult. Although its purpose is quite different, the Solovox's internals are not much different from what you'll find inside a typical tube radio: tubes, resistors, paper capacitors, and a few coils.

The keyboard, of course, has no counterpart in the radio world. It is quite complex, with delicate brass switch contacts and a number of coils and resistors inside. Unless the keyboard has been damaged, however, it should only require some cleaning.

The new tone cabinet worked, but its sound was rather weak and the vibrato didn't work at all.

My first step was to disassemble the keyboard and clean all of the switch contacts with DeOxit spray. I also cleaned the four controls and volume control located under the keyboard.

Those four controls let you tune the keyboard to match your piano and also regulate the minimum and maximum volume. The power switch and volume control are on a long, spring-loaded brass paddle that is mounted under the keyboard. You control the volume by pushing the paddle sideways with your right knee.

Next, I replaced the capacitors with modern units. By the time I was done, the tone was much stronger, the various voices were distinguishable, and the vibrato was working again. The vibrato was harsh, however, creating almost an on/off effect rather than a soft variation of pitch. I remedied this by replacing a resistor connected to the vibrato oscillator tube.

After restoring the electronics, I restained the cabinet to cover a few scratches and even out the color. Then I reassembled everything and mounted the keyboard under my workbench. Here is a photo of my younger son, Peter, trying it out in the workshop.

Both of my sons play the piano, and they enjoy using the Solovox. A single-voiced instrument can't play chords, of course, but the Solovox can create a surprising variety of sounds. And, as Peter told me, you can use techniques such as arpeggios for chord-like effects.

As much as I like the Solovox, I'm not ready to screw it onto our grand piano. For now, it will be mounted on a spare desk in the kids' playroom, where they can play it any time they want.

Solovox Schematics and Manuals

Along with the new unit, I got the original owner's manual and technical manual, both dating from 1948. I also have run across a couple of magazine articles which include schematic diagrams and technical information about the various models of Solovox (J, K, and L). The total documentation amounts to about 50 pages.

You can download this documentation from the following links. These are rather large files—a few megabytes each—and they are in .PDF format. To save a file on your computer, right-click on the link and choose Save Target As.

The Solovox Owner's Manual tells you how to instal and use the Solovox, including settings for register (voice), tone, vibrato, attack, and so on. There are charts showing 77 different settings for orchestral instruments, church organ, and other interesting combinations. It also includes some music written for the Solovox.

The Solovox Technical Manual explains theory of operation and includes a schematic diagram, parts layout diagrams, voltage charts, etc., for Model L.

The Solovox Magazine Articles are from Radio Craft, November, 1940, and Radio & Television News, December, 1948. Written for electronic dealers and technicians of the time, they provide additional technical details, including schematics for models J and K.

Note that the various models are not interchangeable. If you have a keyboard from one model and a tone cabinet from another, they will not work together without extensive modification (which is well beyond my talents).

If you are not able to download the documentation, just send me an email with your mailing address. The charge for the Solovox documentation is US$5 to cover the cost of photocopying and postage.

Thanks to Nils Sundquist of Eskilstuna, Sweden, for creating these electronic files for me to share with other Solovox owners.

Notes from Solovox Owners

Since I posted this article several years ago, I have gotten hundreds of emails from Solovox owners, from as far away as Denmark and Japan. Some of those emails are pretty interesting. For example, did you know that there was a Solovox songbook? Here is a description:

Solovox Album, complied and arranged by John Finke, Jr. for
Theodore Presser Co. of Philadelphia. It has a copyright
date of 1941. It is subtitled: A Collection of Special 
Arrangements of the World's Best Loved Melodies for the 
Hammond Solovox. It contains 32 tunes, including Arkansas
Traveler, Oh! Susanna, Old Folks at Home, Turkey in the 
Straw, Home On the Range and Auld Lang Syne. 

I have never seen that book, but it sounds like a lot of fun.

The following note indicates that the Solovox is alive and well in polka circles:

I am a accordionist and have had a polka band for 22 years.
My first introduction to the Solovox came from America's 
Polka King and First Polka Grammy winner, Frank Yankovic. 
Frank had Solovoxes in his band in the late 1940s when they 
first came on the market and Frank had two of them in the 
band until the 1960s when he went to the casio M-10 keyboard.
Many albums Frank recorded for Columbia records had the 
Solovoxes in use. Frank and his piano player in the band 
harmonized with two Solovoxes. Anyway, I have always wanted
one and yesterday I got one from a oldtimer here. He gave me
the Solovox that he bought in 1968 and used in his band.

In 2001, this email arrived from Hamburg, Germany:

Hello! This is Jurgen Lamke from Hamburg in Germany. I am a 
pianist and organist for North German Radio (NDR). In our 
broadcasting house we have a fine old "Welte-Funkorgel," a 
theatre pipe-organ. In the 1950s, the organist Gerhard Gregor 
installed a Hammond Solovox at this console. We still have 
this Solovox and I would like to repair it for further use. 
I am very interested in the documentation which you offer

In exchange for the documentation, Jurgen sent me two CDs featuring Gerhard Gregor playing the Welte-Funkorgel in the 1960s and 1970s.

This note arrived in 2003:

While helping clean out the basement of an old house, my 
son found a Hammond Solovox keyboard. He was told he could
keep it, as the house was to be sold and had to be emptied.
It looked pretty darn weird to us, never having seen or 
heard of one. The neat thing is that the vintage lettering
on front said "Pee Wee King!" He was in the Country Music 
Hall of Fame and co-wrote Tennessee Waltz and many 
other well known songs. 

Here's another trivia note about the use of a Solovox in recordings:

If you knew Sugar Shack and Daisy Petal Pickin' by Jimmy Gilmer 
and the Fireballs, you may have noticed there was a Solovox in 
both of those songs. Norman Petty, who was also a producer for
Buddy Holly and the Crickets, did that part.

I have received many other emails from people who either owned a Solovox or had a family member who played one in a band. Keep those cards and letters comin', folks!