Wavestation Upgrade

I have had a Korg Wavestation since, oh, I believe 1991. I love it dearly but one thing has always nagged me. Half a year after I bought it, Korg came out with an upgraded version of it, the Wavestation EX, which added lots of waveforms (an additional 2MB, doubling the original’s waveform ROM) including some sorely missed piano samples. Yes I know that the Wavestation is a synthesizer and not a ROMpler, and it’s great for that, but it was also my only keyboard for a while and sometimes you just need some piano sounds. Korg even offered an upgrade set for a while but I remember it to be rather expensive, and I was a poor student… I made do with the piano PCM card set but that was always a bit of a hack.

Nowadays, I could buy the EX upgrade but of course since the Wavestation was discontinued in 1994 (twenty years ago! ZOMG!), none of these are available anymore.

My Wavestation
My Wavestation

But recently I found out that a site called Wavestation Revival has been collecting data on that fabled EX upgrade (and other things) for a while, and very successfully I might add. They have files for OS EPROMs available that can be used to upgrade the WS to the newest OS version (3.19), and also offer some details on installing EPROMs containing the remaining waveforms. Good times! After I had obtained the OS software and the waveform EPROM data, I was ready to upgrade.

My Wavestation's original OS version, 2.28... pretty ancient.
My Wavestation’s original OS version, 2.28… pretty ancient.

While I was at it, I also replaced the failing battery. It’s a regular CR2032 available at many stores from many vendors.

Tools for the upgrade
Tools for the upgrade

The ICs were obtained at buyicnow.com, who not only sell them for pretty cheap but also offer a burning service for those who (like me) do not have an EPROM burner. I am sure you can buy them at many places that offer the same service but this was the one I used and they did a flawless job.

Bottom of my Wavestation. All screws except the ones inside the rubber feet need to go.
Bottom of my Wavestation. All screws except the ones inside the rubber feet need to go.

The first thing to do is opening the box, of course. I unscrewed all screws on the Wavestation’s bottom except the ones in the rubber feet. Those do not do anything except, well, hold the rubber feet…

After all those screws were gone, I could remove the bottom cover. All the chips that need to be changed are located on the logic board (the green one).

The WS logic board. The four waveform EPROMs go into sockets soldered into the empty spots on the left.
The WS logic board.

The first thing I did is carefully lift out the socketed EPROMs containing the operating system and replace them with the new ones.

My Wavestation's original OS EPROMs, WS900828 and WS900928.
My Wavestation’s original OS EPROMs, WS900828 and WS900928.
OS upgrade successful! We're at 3.19 now.
OS upgrade successful! We’re at 3.19 now.
OS 3.19 does not offer any new sounds, but it does offer some new effects, including pitch shifter and vocoder.
OS 3.19 does not offer any new sounds, but it does offer some new effects, including pitch shifter and vocoder.

So this worked out great. The next step, installing the wave ROM chips, was a bit more involved. Wavestation Revival very sensibly recommends installing IC sockets instead of soldering the ROM chips directly to the logic board. Also, every IC gets a buffering ceramic capacitor of 100nF. To do this installation, the board needs to be removed from the Wavestation. My WS’s logic board had a lot of the holes for the new IC sockets clogged with some black stuff that I believe was solder resist. I had to remove that first; I just used a bit of wire which I pushed through each hole in turn using some needle-nosed pliers. Afterwards I could install the caps and the IC sockets.

EPROM sockets soldered, including 100nF buffer caps.
EPROM sockets soldered, including 100nF buffer caps.

After pushing the ICs into their sockets, I turned over the WS and powered it up. Checking the waves revealed…

Et voilà! The original Wavestation's waves go up to 396, and mine now goes up to 484... including #401 Grand Piano.
Et voilà! The original Wavestation’s waves go up to 396, and mine now goes up to 484… including #401 Grand Piano.

Success! I now have a Wavestation EX. Parts cost was about 30€ for EPROMs and shipping. I am very very content indeed!

I still have some upgrades to do. The inverter powering the display backlight (EL foil) kind of hums in a pretty annoying way. I plan to replace the display with an LED-backlit one as described in this article. While I am at it, I will replace the felt strip that buffers the keyboard keys when they go up, hopefully quieting the otherwise excellent keyboard.

Next upgrade will fix the display whine and replace this felt strip, which should make the keyboard much quieter.
Next upgrade will fix the display whine and replace this felt strip, which should make the keyboard much quieter.

After those two upgrades, the Wavestation will again be my dream keyboard.

If you have any questions on the upgrade please feel free to contact me. I also have one more set of OS and wave EPROMs available (because I wanted to make sure I had a replacement if I screwed anything up) which I am willing to part with.

Building an Ambika

After building several Shruthi-1s, I finally bit the bullet and ordered an Ambika kit from Mutable Instruments. This is the biggest DIY synth project I tackled so far. It is a six-voice polyphonic synth with hybrid sound generation, meaning digitial oscillators and analog filters. Here is it with only one voice card (out of a total of six) installed, I will build the remaining voice cards in the next couple of days.

The kit came with PCBs for the default voice cards (they are based on 24dB/oct filters called SMR4). It is possible to choose from different types of voice cards with other filters. One voice card takes about an hour to build; I estimate a total building time of around eight hours for the whole project. I hooked up the one-card Ambika to the band room’s sound system, and it sounds awesome. Very lush, creamy and rich.

Here is the beautiful case it will end up in:

And two of my Shruthis (the one on the left is a regular Shruthi-1 in one of those beautiful cases, the knobby one on the left is called a Shruthi XT):

I love those little synths to bits, but I think that the Ambika sounds even better.

DIY Parts Sources

This is where I collect links to suppliers of hard-to-find parts.

Potentiometer and Encoder Knobs

Odenwälder Kunststoff-Werke (D)
F.K. Kobler (D)Musikding (D)
Banzai Music (D)
Mammoth Electronics (USA)
Bitches Love My Switches (USA) (Bitches love my switches??? Really?!)
Tayda Electronics (Thailand)
Thonk (UK)
Mony Industrial (Taiwan)
Chia Shin Knobs (Taiwan) (bulk only)

Synth DIY

SynthCube (USA)
Thonk (UK)

To be expanded…

Hello world!


My blog is back up.

I have decided to go back to blogging after quite a while doing Facebook almost exclusively. After a while, that seemed wrong. I have some things that I really want to publish on the whole internet, I want control about what I publish, and I dislike Facebook more and more.

I haven’t bothered with resurrecting my old blog posts since they’re more than five years old. Time for a fresh start!