Realistic Musideck
We acquired our first Realistic Musideck because the chrome legs reminded us of Wurlitzer legs. We didn’t know anything else about it, and we did not have high hopes for the sound quality. But it turned out to be very cool, and it’s now one of our favorite keyboards!
First of all, this was obviously not intended to be a high-end keyboard. It’s from the 1960s, it’s feather light, and it kind of looks like a toy. However, unlike present-day cheap keyboards, it does have a lot of fun details: dramatic mirror-finish cheek blocks, a lid that pops up and down on hinges, and leg storage built into the bottom of the case. The reverse-colored keys on the left are bass notes, and there are a handful of (fairly subtle) preset switches on the right.
Historically, companies that dumped lots of money into their organ designs ended up with a slate of unbearably heavy instruments bloated with cheesy sounds and useless features. (Apologies to anyone who still uses their organ’s built-in cassette input.) Today, you can’t give those organs away, although they cost thousands of dollars when they were first released. Still, to maximize profits, companies needed to fill out the low end of their catalog with simple, lightweight, low-cost offerings. The Wurlitzer electronic piano was one of the cheapest instruments Wurlitzer sold; the Realistic Musideck was even more bottom-shelf. The design was apparently even licensed to different companies: in addition to the Realistic Musideck, we have seen this same organ branded as a Whippany Melo-sonic.
Certain aspects of the Musideck’s design are so cheaply engineered that it seems almost spiteful. Instead of one oscillator per note, divided down into lower octaves, the Musideck has one oscillator for every three consecutive notes. If you play two notes simultaneously within the same oscillator, only the highest note will sound. Since all of the bass keys share one oscillator, the entire reverse-color section is fully monophonic. The contacts that trigger the oscillator are just thin wires, and, if you hesitate in your playing, the pitch will warble as the contacts slide into place.
Despite all this, the Musideck has a great analog sound, and the simple design has upsides that more complicated organ circuits do not. Because it doesn’t have thirty sound effects and a cassette player, the organ is portable and lightweight. Also, although it is 50+ years old, every component inside of the amplifier is still readily available. Because there is no power amp, nothing gets particularly hot, so everything tends to work fairly well—except, of course, for the resistors that set the intonation. They have drifted out of spec over the years, and replacing them is complicated by the fact that their color scheme is completely inscrutable. Normally, resistors have between three and six bands, which are color-colored so that you can tell the value of the resistor at a glance. The color code is the same today as it was in the 1960s, so you can always tell the value of almost any resistor no matter when it was manufactured. Musideck resistors have one band, or sometimes two. What does that mean? Who knows.
To tune the Musideck, we clip out each intonation resistor, leaving the leads in place so that we can attach alligator clips to them. Then, we can either use a decade box, or manually substitute different resistors until we find the value that gives us the correct pitch for each note. (A decade box is a device containing a series of switches that allow you to dial in specific resistor values.) In every Musideck, the highest note in each oscillator is controlled by a potentiometer. Some models use a potentiometer for every note, so tuning doesn’t require changing resistors—but there’s a catch, of course. New resistors will last years, while potentiometers are prone to shifting, so the tuning pots may need light adjustment whenever the keyboard is moved. But it’s easy to open the lid, and, with a little practice, adjusting the potentiometers is as simple as tuning a guitar. The tech just needs to watch out and not touch any part of the circuit while it is energized—particularly the power supply components, which are typically found wired point-to-point underneath the lid, on the left.