Build Quality

The AN1x has a sheet metal base that acts as the foundation for the synth. The one-piece painted blue plastic enclosure mounts onto this metal base. Onto this plastic enclosure are mounted all the internal components, like the keyboard and all the PCBs. For the main board, there is a metal shield that it mounts to. Some of the jacks on this board are reinforced using the metal shield and screws. Also, the pots are reinforced with sheet metal and nuts, which is nice to have.

Other than a small amount of sheet metal inside for reinforcement, this combination of a plastic enclosure and metal base is all what gives this synth structural rigidity, for better or worse. I wouldn't want to drop or bump this synth, as the plastic enclosure would probably easily crack.

Yamaha has provided some adjustment pots inside, for a few of the functions.

According to some websites, you do not want isopropyl alcohol anywhere near this synth, as the blue paint will come off. You can only use a soft cloth dampened with water for cleaning the blue finish. The blue paint also seems to scratch easily.

Due to this synths age, the 1-8 pots on this synth have a reputation to wear out, and they can also skip values. Luckily, you can buy similar replacements. The rotary switch on the right side can develop a wobble, however, a replacement for this switch is hard to find. 

These synths have much better reliability than Roland JP-80x0s. The electronics of the AN1x should last a long time.

There is a software bug that produces clicks when you set the delay to sync with MIDI. I believe there is an updated OS that fixes this. 

The AN1x was made in Japan.

User Interface

The AN1x's keyboard has a light action to it, compared to other synths I own. The keyboard doesn't have a nice solid feel to it, like a Prophet Rev2 does. Also, when the keys return to their resting position after being let go, they make much more noise than other keyboards.  This can be slightly annoying when you are playing the instrument, and the sound seems to be made worse by the plastic enclosure. Some button presses will also resonate within the enclosure. The keyboard is otherwise fine. 

The knobs and pots on this synth are some of the worst I have seen. The black plastic knobs have a weird over-stylized shape that makes them uncomfortable to use for extended periods. I ended up replacing mine with larger diameter rubberized knobs. The pots for the assignable knobs have a lot of slop in them when they are rotated. These same pots also have a surprising amount of side-to side wobble. Both types of slop are normal in these synths, even when the pots are brand new.

The layout of the user interface is organized like a matrix, where you use a button or rotary switch to select the category of functions you want to use.  Knobs 1-8 can be assigned to do almost anything you want on the default category page, for quick access to frequently used functions. 

The interface layout is nowhere near as bad as some say it is. While you don't get one knob per function, the functions are all grouped together with other similar functions. It is kind of like the ribbons/tabs you see on some Microsoft programs. You will need to look at the manual often, however, to fully learn and remember everything this synth can do.

The amount of functions/settings this synth has, and the ways that they can manipulate the basic waveforms, makes this synth stand out from similarly-priced synths. This synth even does some FM synthesis, however it is not as advanced as on a DX7 or SY77.

Patch naming is very well implemented on this synth. No twisting encoders is needed, just press and hold a switch, until you scroll to the character you want.

When knobs 1-8 are pressed, the synth will reveal what the current setting is, and pressing while turning a knob lets you change values in smaller increments.

This synth only has 128 slots for your patches. Because of the large number of ways sound can be manipulated, I find this to be not enough space. You will need to do sysex dumps to move patches in and out of the synth. I wish this synth had a floppy drive or a memory card slot, but it doesn't.

Overall, this is an interface with cheap-feeling components, but with a powerful synthesis engine inside.

Sound

The overall sound of the AN1x tends to be "airy" and "smooth", to me. It is great for trance and other genres where a dreamy, lofty, airy, trance-like sound is needed. The AN1x can also do bass, but due to its naturally smooth and airy sound character, getting a growly aggressive sound is challenging. 

On a initialized patch, the sound can be slightly "digital", "hi-fi", or "glassy". If that's not what you want, the sound can be made to sound more saturated/dirty by using the feedback knob. This can also effect the way the filter sounds.

The AN1x can be made to make a polyphonic supersaw sound, without the need for a supersaw oscillator. 

The effects are pretty good and provide many settings, but the distortion effect is weak on this synth.

The sound of the AN1x can sometimes give a hint of a dated 90s feel to it, but it is only a hint.

Conclusion

If you are looking for a powerful synthesis engine, can tolerate a build quality that feels like Yamaha was cutting down a lot on production costs, and are ok with maintaining a 90s synthesizer, consider a Yamaha AN1x. 

Although it is obvious Yamaha cut down on production costs to provide a powerful synthesis engine at a specific price point, the quality and longevity of the internal electronics is better than some of the competitors of this time period.

The "smooth", "airy", and "dreamy" sound of the AN1x works great with genres where this is desirable. If you are looking for a very aggressive, rough, or growly sound, then there are synthesizers that are better at that, than the AN1x.

PROS

• Lots of parameters to sculpt your sound

• Built-in effects

• "Airy" and "dreamy" sound

CONS

• Can have a 90s hint to it, sometimes

• Plastic housing can get damaged easily, doesn't feel solid

• No floppy drive for patch storage