In Japan, as early as in 1935, Yamaha released Magna organ, a multi-timbral keyboard instrument based on electrically blown free reeds with pickups. It may have been similar to the electrostatic reed organs developed by Frederick Albert Hoschke in 1934 and then manufactured by Everett and Wurlitzer until 1961. Clavioline repair maybe one of the earliest valve vacuum tube synthesizers Published on Feb 28, 2019 markusfuller 'Here is a simple repair on the Clavioline. This is one of the earliest ever synthesizers. There are 3 ways to play notes: Click or tap the onscreen keyboard. Play with the bottom two rows of keys on your computer keyboard (z, s, x, d, c, v, g, b, h, n, j, m, etc.).

Gibson Clavioline Keyboard Instrument (1953)

The clavioline is a monophonic electronic musical instrument. Invented by the French engineer Constant Martin (1910-1995) in the 1940s, it is considered one of the precursors of the synthesizer. This is a vintage Clavioline tube keyboard/synth that I was selling on ebay. The video is to demonstrate functionality of the instrument and does NOT show t.

The Clavioline is an early electronickeyboard instrument, similar to my Hammond Solovox.Both of them are monophonic (single voiced) and tube powered, consisting of a keyboardand an amplifier.

The first photo shows my Clavioline after restoration. In the second photo,my son, Peter, is seated at the keyboard. Click the musical icon to hear him playing a brieftheme from the well known 1962 song, Telstar.

Description

My Clavioline is a Gibson, shown here in some mid-1950s ads.

As illustrated, a Clavioline can be used in two ways. First, likea Hammond Solovox, it can be mounted on a piano and played as an adjunctto the piano keyboard. Or, mounted on a tripod, it can be played as a standaloneinstrument.

Either way, the artist must be sitting, in order to operate the knee-levervolume control, or 'expression' control, as termed in Clavioline literature.

Every Clavioline was created under license from the inventor,Constant Martin, as seen on my keyboard's ID plate:

In the United States, Claviolines were manufactured by the Gibson instrumentcompany. They were also built by Jörgensenin Germany andSelmer in England.Since the Jörgensen and Selmer instruments differ in construction as well asfeatures, I'll refer you to the previous links for details about them.

Martin applied for a U.S. patent in 1948 and on August 7, 1951, he was grantedpatent 2,563,477, 'Electronic Musical Instrument.'Click the thumbnail to read the patent, with the full description andoriginal drawings:

If you're looking for a layman's explanation of how a Clavioline works,the patent is not the place to start. Like most patents, it is writtenin a dense polyglot of legalese and techno-jargon, aimed at establishingprecedence and forestalling infringement. Furthermore, since a patent isdrafted to protect ideas and principles in the broadest possible fashion,this one doesn't literally describe the Clavioline as it was commerciallyrealized. Still, it's interesting to see a contemporaryexpression of Martin's idea.

Interestingly, the last page of Martin's patent description references an earlier (1939)patent, number2233258, 'ElectricalMusical Instrument.'Held by Laurens Hammond and John Hanert, that isthe seminal patent for the Hammond Solovox. Some long winter's evening, I'llneed to sit down and compare the circuitry of these twosimilar instruments and decide how different they really are. TheClavioline has more voices and a larger octave range, but presumablymore than that was needed to establish that it wasn't merely a rehashof the earlier Solovox design.

The only Gibson service data that I have found so far are these two schematic diagrams for thepower/amplifier chassis and keyboard chassis:

Apologies for the low quality of these schematics. If you have a more detailed Gibson servicemanual, or even clearer copies of these schematics, pleasecontact me.

I also have obtained some Selmer documentation, which is not terriblyuseful, owing to differences between the American and English instruments. Thispage from the back of one manual is not identical to the Gibson keyboardschematic, but perhaps it will help you identify a few more items in theblurry Gibson scan:

Finding a Clavioline

I found this Clavioline at a crowded estate sale in 2011. The sale was located in a tinyhouse, whose every room was crammed to the ceiling with shelves for antiqueradios and other electronics. Thefellow in this photo was on the phone, describing every radio in the houseto someone on the other end.

I didn't see any radios or TVs that I wanted, but this little keyboardcaught my eye. I recognized the name Clavioline as a monophonicinstrument like my Solovox.

The price ($250) was too high to tempt me, but I returned the next day andmade a deal for half that price. Here is my Clavioline after unloadingback at home.

Removing the back cover reveals the speaker, power cord, connecting cable,and the power/amplifier chassis. To transport the Clavioline, you stow thekeyboard unit in the back of the cabinet and pop the cover back on.

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My Clavioline has no identifying information other than the ID plateshown earlier, which says Made in France. After a little research, Iconcluded that it's a Gibson model, sold under license in the United States.Since its components (capacitors and whatnot) are also of U.S.manufacture, I presume the whole thing was manufactured here,not imported as the ID plate suggests.

Some time later, I saw photos of an identical model with a stickeron the back of the speaker that said Gibson Ultrasonic. Perhaps mineonce had the same sticker, but it fell off and became lost.

First Power-Up

Moving my Clavioline to the workshop, I cautiously powered it up, using myvariac and watching its ammeter for excessive current draw.

The Clavioline worked . . . sort of. I could hear notes from many of its keys,but they were sometimes intermittent. A few of the tone switches had an effect,but others seemed to do nothing, and the vibrato switches were also inoperative.

Not to worry, every 60-year old tube device needs service, chiefly in theform of new capacitors. It's not surprising that the keyswitches andcontrols need cleaning, too.

Electronic Restoration

We'll examine the two Clavioline chassis separately, starting withthe keyboard unit.

A Clavioline is not especially complex, compared to other tubeelectronics. A full restoration will take a number of hours, however,so don't expect to give yours a complete overhaul in an evening.

Keyboard Unit Disassembly

By removing a few screws, you can take off the large cover plate on thebottom of the keyboard unit. This exposes the tubes, potentiometers, andother electronic components.

After removing those screws, I put them back into the holes they came from. Thisis a great way to avoid losing parts!

The pink tubular components are 'Tiny Chief' brand plastic-coated paper capacitors.This type of capacitor is notoriously unreliable and should always be replaced,as explained in my recapping article.

The front panel of the keyboard unit is secured by ten screws:

When you remove the front panel, all of the white keys will rise upa little on their springs, although they are still held on by screws fromthe back.

Removing the panel exposes the rocker-style control switches, which selecttone combinations and vibrato effects. When a switch is toggled,its blade-shaped upper contact completes a circuit with two or three springycontacts below. As the photo shows, some of those contacts are dark with dirt and oxidation.

The control switches have either two or three springy contacts and thecircuit is completed when the blade touches them,thus activating the tone filter or other components wired to the contacts.

Cleaning the Control Switches

I'll clean the control contacts with Q-tips dipped in DeOxit D100L electronic cleaner.Don't press too hard on the contacts, lest you deform them. After wetting the Q-tip with DeOxit, I gently twirled it on each contact until the discoloration went away.You also need to clean the edge of each blade, of course.

Here are three switches after some cleaning.

Cleaning the Keyswitches

The keyswitches are similarly constructed, but they are momentary-contact switches,completing the circuit only while you hold the key down. To clean them, you'll needto remove the switches, which come out in three banks, screwed on from behind.

The frame has two rows of slots that expose the springy contacts for the keyswitches.The five rubber bumpers protruding from the frame are in line with the black keys.When you release a black key, a small lip on its end hits the lip on the bumper and thus preventsthe key from rising up too far. (The front edges of the white keys are similarlyheld when at rest, by the edge of the keyboard front panel that we removed earlier.)

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Each keyswitch has two springy contacts below, and every keyswitch blade isconnected to chassis ground. Depressing the key grounds both contacts, witha very slight delay between touching the first and second contact. Thisensures a clean attack for the note, without any electrical pops or clicks.

As with the control switch contacts, I dipped a Q-tip in DeOxit and twirledit on each set of contacts to clean them. After finishing the first bank,I reinstalled it and proceeded to the second bank.

The lip on one of the black keyswitches had broken and become lost. I cuta little piece from a popsicle stick and glued it on with epoxy. Notas beautiful as an original key, but now it works exactly the same!

Studio one free vst vocal. The next photo shows an important detail.Before removing the third bank of keys, you must unsolder this wire, whichconnects every keyswitch to chassis ground. Solder this wire back in placewhen you reinstall the bank; a secure ground connection is critical forkeyboard operation.

Eventually, all of the keyswitches were clean and back in place.

Replacing Capacitors and Resistors

Recapping is a routine practice for everytube device from this era. Since this Clavioline article is likelyto be read by non-radio folks, I'll describe the basic process inmore detail than usual.

How to Replace a Capacitor

This photo shows the keyboard chassis andthe tools that I'll use: a solderingiron, wire cutter, needlenose pliers, bulb solder sucker, anda couple of steel tweezers.

The Clavioline chassis is easy to work on, compared to most radios and TVsof the era. Components are neatly arranged on phenolic terminal boards andtheir connections are readily accessible, rather than buried underother components and wires.

We'll begin by replacing the capacitor shown in the next photo. It's likelya replacement, installed during past service. These whitetubular caps were no better than the pink Tiny Chiefs, so I'llreplace it even though it may be a few years newer.

The old capacitor's value is .025 mfd. The schematic calls for .020 mfd. I'll replace itwith the modern value, .022 mfd. A difference of .002 from the specified value willnot matter. Most old components were manufactured within a tolerance of20% above or below the nominal value, so a difference of .002, or 2%, is wellwithin the needed value range.

I carefully note where the capacitor is connected and then snip each end.Then I can melt the solder on each terminal and remove the wire stubs witha plier. This is easier than trying to work the wire loose from theterminal while the capacitor is still connected, which can damage theterminal if you yank too hard.

After I remove the first wire stub, I reheat the joint and removeexcess solder with the solder sucker. I repeat the process on the second terminal.

The new capacitor is smaller than the original and it will easily fit the space.I snip its ends and bend them to fit neatly around the terminals. If a terminalhas holes (these don't), you can run the new capacitor's lead through thehole and bend it around the terminal a bit, before snipping to length and crimping.

Next, I crimp the pre-formed wire ends onto the terminals and secure them with newsolder. Always heat the joint first and then apply the solder to the heatedjoint rather than to the hot iron. This distributes melted solder evenlythroughout the joint. It is very bad practice to melt solder on the ironand let that drip onto a cold joint.

Sometimes, when a delicate component is connected to a terminal, I'll temporarilyclip a metal tweezer onto that component's lead, to act as a heat sink andprevent overheating damage. That's not necessary in this case, since I'm workingquickly and heating the joint only long enough to flow the solder intoand around the joint.

We have replaced one capacitor. Only a few dozen more components to go!

Replacing the remaining capacitors was simply more of the same.The process looks laborious when you document every step, but with practice,you'll be able to replace a capacitor in only a minute or two.

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Replacing Resistors

In a typical radio or TV restoration, I leave all or most of the original resistorsin place. Resistors are more reliable than capacitors and in many cases theirprecise value isn't critical in the first place.

Unless otherwise specified, resistors in old tube devices are expected to bewithin 20% of their nominal value, and in many cases a radio or TV will worknormally even if a resistor's value has drifted beyond that range.

The Clavioline is a musical instrument, however, with circuits intended tooscillate at particular frequencies. The resistors in itskeyboard chain are of extremely high precision and stability, and they have unusual valuesrelating to musical frequencies, such as 6300 ohms, 6670 ohms, 7074 ohms, and so on.

The high-precision keyboard chain resistors seem to be fine—each keyis in tune relative to the others—and so I won't touch them. Most of the other resistorsare of the everyday carbon variety, however. I'll replace those as long as I havethe chassis on the workbench.

Replacing resistors on the terminal boards is the same as replacing capacitorsthere. Remove the old resistor and solder in the new one.

Here's a resistor mounted in a different spot, on potentiometer VC1, whichcontrols the vibrato. The resistor's value is 5.1K ohms, indicated by thegreen-brown-red color bands:

Replacing this resistor is easier if you first unscrew the potentiometer fromthe keyboard frame, as shown in the previous photo.

One end of the resistor connects to a terminal on the potentiometer. The otherend is soldered to the potentiometer's metal case, which connects to thekeyboard unit's grounded chassis through its screw mount. Here is thenew resistor in place:

Cleaning Potentiometers

While I have the potentiometer out, it's a good time to clean its interiorusing DeOxit or a similar electronic cleaner. In the previous photo, notice the little openingin the potentiometer case near the terminals. Spritz a tiny amount of cleaner into thatopening and then turn the potentiometer all the way back and forth a numberof times, to distribute the cleaner. Dab up any excess cleaner that dripsout of the case and let the Clavioline sit overnight before you applypower again, to make sure the cleaner has evaporated completely.

I cleaned the other carbon type potentiometers in the same way. Thelarger potentiometers (without openings in the case) are the wire-woundtype, which normally requires no cleaning.

The knee-operated volume control has a different type of potentiometer.The rotary type shown earlier has a metal wiper inside, which moves in an arcaround a resistive carbon track, producing lower or higher resistance asyou turn its shaft. The potentiometer shown next also uses a metal wiper on a resistivecarbon track. However, the track is a rectangle on a flat phenolic boardand the wiper moves back and forth in a straight line (actually, a veryshallow arc) on the board.

These photos show the volume control in operation:

Here's a little animated GIF that show the control's operation more clearly.

My volume control worked perfectly without cleaning, so I left it alone.If you wanted to clean it for some reason, I would be careful not to rubthe resistive track too hard, lest you wear it off and ruin the potentiometer.

When the Clavioline is reassembled, a long, L-shaped lever is mountedon this volume control, so that you can move it with your knee.

Clavioline Keyboard Chassis Restored

This photo shows the fully restored Clavioline keyboard chassis fromunderneath:

All told, I replaced about 50 capacitors and resistors in this chassis, in additionto cleaning the keyswitches, control switches, and potentiometers.

Power/Amplifier Chassis Restoration

The second Clavioline chassis contains circuits for the power supply andaudio amplifier.

This chassis is far simpler than the keyboard chassis and its restorationwas straightforward. Again, in the interests of reliability and longevity,I replaced its resistors as well as the electrolytic and paper capacitors.

Two of the electrolytics are multi-section cans mounted upright on thechassis. I left the cans in place above the chassis, but disconnected theircontents and wired new capacitors underneath. You can read about severalalternative methods forreplacing electrolytic cans in myrecapping article.

This photo shows the power/amplifier chassis after restoration:

As you may recall from earlier photos, this chassis mounts upside downinside the speaker cabinet. Its power switch and green pilot lightprotrude through an opening below the cabinet's handle.

Cabinet Restoration

The Clavioline cabinet is covered with leatherette, a vinyl-coated fabric.When I first got my Clavioline, it had a tear in the front near the speakergrille, and assorted scuffs and scratches.

The first step was to clean the covering with Windex and reglue the flaps ofturn fabric. Next, I used black liquid shoe dye to conceal the scratches andgive the covering a uniform color. In the following photo, I have begunby coloring the strips along the sides.

Notice the narrow band of exposed plywood around the speaker opening. Perhapsthis was originally covered with a thin strip of leatherette, which fell off.I don't have leatherette on hand, but at least I can color the bare wood blackso that it doesn't attract attention.

After coloring the whole cabinet, it looks much better.

You can still see some marks of age, but I wouldn't be embarrassed to bringthe instrument onstage.

Final Thoughts

Here is my Clavioline after restoration:

For this photo, I mounted the Clavioline on an old, heavy-duty camera tripod.I assume that the original tripods were similar, based on pictures inthe magazine ads, perhaps with a wider bracket at the top to steady theheavy keyboard against pushing on its ends.

Of course, in a performance setting the speaker would be aimed outwardat the audience, not perched in front of the keyboard as in this photo.The connecting cable is long enough to place the speaker alongsidethe keyboard.

I haven't yet had time to try out all of the Clavioline's different voicesettings, much less compare its performance to my Solovox. Perhaps when myson comes home for the holidays, we can set up both instruments side byside for comparison, and even record a couple of audio clips to addto this article.

I'm seeking a few minor items. My Clavioline is missing the rightmost controlkey, labeled P. If you have any spare key for sale, I'd be interested in that.A working key with a different label would be better than no key at all.

I'm also missing the knee lever for the volume control. I canuse a makeshift piece of bent metal in the meantime, but it would be niceto have the original article. The following photo shows the knee lever froma Selmer Clavioline, which is similar but not identical to the Gibson lever:

Lastly, as noted earlier, I'd like to find a complete Gibson service manual,as well as an owner's manual. If you have any or all of these items,kindly contact me.