Instrument Review - Casio DH-100

Casio will always have a special place in my heart. Their synthesizers always seemed to straddle the categorization between toy and professional instrument. The Casio DH-100 is no exception. Casio's wind synthesizer looks like a toy, sounds like a toy, and sometimes feels like a toy... But it is elevated by some really basic features and is surprisingly a very capable device.

Build 

What can I say? The plastic looks like the typical cheap plastic used on the Casio synths of that era Soni wouldn't want to drop this device but apart from that the thing feels well built. 

First, the keys are metal and playing it feels natural to a wind musician, with all plugs and buttons feel secure and functional. My only complaint would be that the keys can be very sensitive and if operating without the breath control you can have some moments where you accidentally sound a different note as you change fingering.

The battery compartment door doubles as a thumb rest and neck strap holder and there is no reason for concern that either would snap off like a cheap knife from its handle - both are part of a solid piece of metal providing stability and giving the instrument some added weight. 

There are some electronic issues that arise with these synthesizers that I will address later but I wouldn't fault the device for that and it is really an easy fix for anyone with even a basic knowledge of electronics and soldering.

Cosmetics

This device looks like a toy. While synthesizers like the Lyricon, which came out a decade earlier, closely emulated the appearance of a flute, and other Japanese wind synthesizers had more angular and futuristic appearances, the DH-100 looks like a toy. The device is simple looking (especially the key layout) and while it features its own sound output unlike it's competition, it accomplishes this by giving this a saxophone-like shape and placing a speaker in the bell.

Sound

The sound of the DH-100 is very simple. With only a few tones, they are of the generic 80s variety, like what you would find on some of their cheaper square wave synthesizer offerings. The portamento is a nice touch and easy to implement, with pressing the narrow key with your knuckle as you play and feels completely natural. 

The breath control uses a rudimentary method of providing some dynamic playing by first sensing the tone-on velocity and then if the note is sustained, the aftertouch value is changed. It gets the job done.

What makes this device interesting is the MIDI out so that you can use this to control whatever you want. I have heard this play with some synthesizers that have some excellent wind sounds and with various effects this seemingly simple device can be a pretty expressive controller that givers non-keyboard players accessibility to the sounds of a synthesizer at a value price.

Features

This synth doesn't have much features. It has 6 tones that sound very close, portamento, volume, transpose, breath control, MIDI out, and audio out (as well as a speaker). Casio also provides for a couple different fingering methods - one a simple recorder style of playing and another that uses various fingerings that help provide for a greater octave range, but with added playing complexity.

Overall

I think that taking into consideration everything about this synthesizer, from its lack of advanced features and simplistic appearance to it's surprising functionality and ease of use, this can be a beast in the right hands. Considering wind controllers are still rather expensive, this 30+-year old synth and controller gives you some bang for your buck.

Issues

If you Google the Casio DH-100 you may see websites and forums detailing a "squeal" due to the result of a dried or leaky capacitor. My DH-100 had this issue. The "squeal" sounded like a sustained digital hiss and squeak, with the faint sound of the note as each key is depressed. 

After a quick search online, I had ordered a replacement capacitor - 33 uf 6.3v (I believe you can go higher on some of the values but the closest value I had found was a 16v capacitor). 

I removed all the screws carefully, as with old plastic sometimes the housing for each screw can break. As others noted, there is also a screw in the battery compartment. 

Once open the synth separates with a ribbon cable attaching the PCB for the keys to the main PCB. There in a spot labeled C39 was the offending capacitor. I had pulled the capacitor gently from the board using tweezers and then unsoldered the legs.

Located just off to the side of the capacitor are two holes. You can see the traces lead to the capacitor. Making sure the polarity is the same (there is a plus sign in a circle on the positive end).

Place the new capacitor in the holes, solder it into place, and then clip the legs. 

You should be done with the repair and after assembly the synth should be good to go sans squeal.

Hear are some pictures of the process:

Now after I had fixed this the squeal was gone and the synth played... But very softly and the breath control did not seem operational. This may be a result of low batteries, as I had later discovered from the manual that low batteries can result in a dim power light, low volume, and "malfunctions."