Maxon AF-9 Auto Filter

The AF-9 is generally easy to adjust. However, it is not easy to see how the three small switches for Filter, Drive, and Peak are set when looking at them from more than a few inches away. Maxon might have made the base of the switches red instead of black to make the position easier to see. You have to try to move them to figure out the current setting; a minor issue. Also, the footswitch does not give any tactile feedback when turning the effect on and off and if you don?t depress it fully the effect will seem to turn on but not stay on after releasing pressure. I?ve never had a TS-9 and I don?t like this style switch. The sensitivity and peak sliders are easy to adjust and their settings are easily visible. However, when playing with single coil pickups of average output I have to max out the sensitivity control to activate the filter on some notes. The sensitivity slider could have been designed with a higher range. Again, more of a comment than a problem.

The AF-9 produces a resonant and vocal auto wah sound in a very compact package. The analog sound is rich and truly impressive, especially when compared with larger units of the same variety. I AB?d this with my 1970s Mu-Tron III. Both units sound great but have different characteristics. The AF-9?s VCF has a faster and steeper response curve than the Mu-Tron, with a more abrupt sensitivity threshold. The filter sweep is wider given the same attack. The AF-9 exhibits more filter jitter in the presence of a decaying signal (i.e. a strummed chord allowed to ring), indicating that it is probably more sensitive that the Mu-Tron. This is not necessarily a bad thing. It is just different. In a quick blindfold test, my drummer son preferred the vowel-like quack of the AF-9 to the more subtle and wispy sweep of the Mu-Tron, but he said they sounded almost the same. There are 12 (3 x 2 x 2) switch settings alone before beginning to adjust Sensitivity and Peak slider, so there are lots of sounds in this box. These settings mimic the Mu-Tron?s exactly, making it obvious that Maxon?s engineers had their sights set on providing the same capabilities. Setting Drive to ?down? produces synthesizer type sounds that are interesting but I would generally not use this setting. Also, I find the ?high? setting on the Range switch too thin for my uses. So for me two of the three switches are fairly moot, but the choices are there. With the Mu-Tron, I use these same settings in conjunction with the low pass (LP) filter for its rich sound. But the AF-9?s LP setting is a bit too dark for my taste, so I quickly adapted to the band pass (BP) setting which has the most vocal and liquid quality of the three.

Maxon makes quality effects. The box is solid. Don?t step on the switches or the sliders.

This is a high quality compact effect. I bought it for live use, where my Mu-Tron III is a pain due to its size and oddball bipolar power supply. Size and convenience notwithstanding however, the AF-9 holds its own and then some when AB?d with the Mu-Tron III. Overall, it?s a sweet sounding box. If you like VCF effects, this box will make you want to sit and play, it sounds that good, especially with clean guitar tones. With both boxes in front of me, I ended up playing through the AF-9 more. Turning them both on was rather intense, but that?s another story ?