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Changing Input Voltage on a Roland HP107e-RW Electric Piano

Making a keyboard from the UK run on USA power

Electrical power grids around the world provide electricity to their end users at a handful of different voltages and frequencies. For example, consumer electronics in the USA typically operate on 100-120 V @ 60 Hz while in the UK most everything runs on 220-240 V @ 50 Hz. In addition to the voltage and frequency variations, there are a handful of power cable plug shapes that various regions use too. People generally don’t have to concern themselves with all this information unless they are traveling or moving abroad and taking their electronics with them.

Friends of ours recently gave Katie a Roland HP107e-RW electric piano they had purchased while living in the UK. When they moved back to the USA, they brought the piano and quite a few other items with them that all ran on 230V. To power those items on the US electrical grid, they purchased a step up converter.

rear product label with model number and serial number

This particular model is the HP107e-RW. There are probably several other similar models for which this modification would work.

Instead of buying a bulky step up convertor to run the piano at our house, I wanted to convert the piano to run natively on the US electrical grid. In order to make this possible I needed to do 2 things:

  1. Change the shape of the power cable plug from UK style (Type G) to NEMA 1-15 ungrounded (Type A)
  2. Change the input voltage from 220-240 V to 110-120 V

Changing the power cable plug was easy. The power inlet on the piano is an IEC 60320 C8. Many of the electronic devices I own use the Type A cable I needed to replace the Type G cable. Swapping out the cable was simple, but that only changed the shape of the plug, not the voltage.

Interestingly, the Type G plug was actually a wrapper around the head of a Europlug (Type C) plug. This was perhaps a cost-saving measure.

an opened Type G plug

A sneaky Europlug hiding inside the Type G plug.

Changing the input voltage was a little harder. Some consumer electronics have little voltage switches next to the power inlet that are easily accessible on the outside. I didn’t see one of those, but sometimes the switch (or jumper) is inside the chassis on the power PCB.

To get a look at the power situation I opened up the top of the piano. That required removing 8 screws grouped in 4 pairs along the top rear of the piano, then sliding the top board forward and lifting it off. There are no wires or other connections made to the top board.

rear of piano with arrows schowing locations of screws to be removed

The blue arrows indicate the 8 screws that need to be removed to take the top off the piano.

After opening up the top I found this beefy power transformer staring back at me. There was no super convenient voltage switch, but surprisingly the input pins on the transformer were labeled—an easy solution! The fix was simple…desolder the black hot wire from the 230 V pin and resolder it to the 120 V pin.

internal power transformer with voltage labels

The label on the transformer indicates what voltages are expected on the input pins.

CAUTION: Before beginning this surgery, I recommend isolating the transformer from everything else. Unplug the input power cable from the wall oulet AND disconnect the output power cable connector from the main PCB. As with all things electrical, you could kill yourself if you don’t know what you are doing. Be safe! Be smart!

Interior look at cable connection from transformer to PCB

Out of caution I unplugged this cable connector before unsoldering and resoldering the cable to the transformer.

After moving the hot wire to the correct input pin, reconnecting the cable connector to the PCB, reattaching the top board, and plugging in the new power cable the piano fired up perfectly.

Let me know if this helped you. If you fried your keyboard or yourself, sorry, I am not responsible for your mistake. Better luck next time! 😉

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The Inception of Keyboard Instruments

Is every new technological development just a deeper dream state?

Sound is basically waves of pressure changes. The exact definition is more complicated, but essentially we perceive sound because our ears decode the frequencies of oscillating movement of particles in gases, liquids, and solids. There are many ways to generate sound waves, such as plucking guitar strings so they vibrate, or hitting a membrane like a drum head.

Woodward Avenue Presbyterian Church pipe organ. Photo: Wikimedia Commons

Pipe Organs

A long time ago, people discovered that sound could also be made by blowing air through a pipe with a opening on the side, thus inventing the whistle. They also found that a range of tones could be produced by assembling a group of whistles with varying lengths and diameters. Then they attached a controller (called a keyboard or manual) so that one person could “play” this collection of pipes. Their invention is what we now know as the pipe organ.

At the start, pipe organs had only one timbre – a basic whistle sound, but over the next several hundred years, smart inventors and musicians made improvements in the technology. They found ways to emulate lots of other instruments, like brass, woodwinds, percussion, and even human voices. Their hope was to fully replicate those real life instruments.

a pipe organ console

Organ console at the United States Naval Academy chapel. Photo: Wikimedia Commons

As features were added, pipe organs evolved into enormous, elaborate, and expensive installations, increasingly more complicated to play and maintain. While these pipe organs were truly amazing inventions, capable of creating complex and beautiful music, they were actually quite poor emulations of the real life instruments they were intended to replace.

Still, we humans are adaptable and we fell in love with the sound of pipe organs, learning to appreciate the instrument for what it was, not what it wasn’t.

Electric Organs

a Wurlitzer organ

Wurlitzer 4100 BW Electronic Spinet Organ (1959-1963). Photo: Wikimedia Commons

Eventually, we discovered electricity and began to harness its power to create electromechanical instruments. Creative minds developed things like vacuum tubes, tone wheels, and transistors. Companies like Hammond and Wurlitzer implemented tone wheels to generate sounds approximating a pipe organ.

However, similar to the pipe organ, this new technology was a brilliant invention that poorly emulated its predecessor. These new organs were affordable alternatives to pipe organs, so in spite of being a bad imitation they became popular with smaller houses of worship. Traveling musicians took advantage of the portability of these smaller organs too, making their sound common in popular jazz, blues, and rock music.

Once again, our ears grew accustomed to the sound of the imitation, developing an affinity for the quirks of its particular aesthetic.


keyboard on table

Yamaha DX7. Photo: Wikimedia Commons

As the march of progress continued, electronics became smaller and more powerful. Engineers found ways to replace the delicate mechanical parts in electric organs, which were subject to wear and tear, with completely electronic sound generators. Lightweight, all electronic keyboard synthesizers used a variety of methods in attempts to replicate the sounds of their heavier electromechanical ancestors.

But just like before, history would repeat itself. The new emulators were incredible technological achievements that fell short of their goal of replacing the old technology. Though they lacked the ability to fully replicate the previous generation, they possessed attributes that eventually found an audience of connoisseurs that valued them not just in spite of their glitches, but because of their unique properties.


Today, we synthesize the sounds of the old technologies with computers and keyboard MIDI controllers. While initially computers could only crudely imitate the old masters, DSP technology is progressing rapidly. CPU speed and available RAM are no longer the main limitation factors. As the computational power ceiling continues to rise higher and higher, software programmers are able to provide increasingly nuanced emulators that can easily fool the listener into believing that the software is actually the real thing.

The Inception

official Inception film poster

Inception poster from IMDB.com

At this point, if you’re still reading, then you probably can see how this history correlates to the plot of the film Inception. Each new technological breakthrough has been like a deeper dream state, where the simulation moves further and further away from reality.

Real instruments
→ Pipe organs
→ → Electric organs
→ → → Keyboards
→ → → → Software

However, just like in the film, while each level becomes more strange and abstract, the deepest level — Limbo — actually approaches something most like the real thing or maybe even better. Today’s emulators delve into such detail and are able to control even the most minute aspects of the sound, that it won’t be long before they easily eclipse the believability of the old technology. In fact, we may already be there.

A few years ago (when the emulators weren’t half as good as they are now), a friend of mine (who has very good ears) dropped by the studio to hear a song I was working on. When the B3 organ kicked in during the chorus, he declared, “That organ sounds great. There’s nothing like the real thing!” Muwhahaha! The smoke and mirrors of software emulation had worked.

Inspiration for This Article

This idea of how keyboard technology relates to Inception came about through a discussion with my friend Hoss. Over the weekend we were working on the keyboard parts for our band Rudisill’s next album Take To Flight. In between takes of an organ part we marveled at the realization that the software he was using was an emulation of an emulation of an emulation — a truly strange scenario.

Follow Rudisill to hear about the new album when it is released later.

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