Maxon 9 Series Reviewed

Maxon continues to improve and refine its 9-Series effect pedal line. From the company’s early years in the 70’s manufacturing effects as an OEM for Ibanez as well as under its own brand, to now with improvements to circuits such as the inclusion of true-bypass using quiet switches, Maxon’s design and engineering team have continued to explore new territory while never forgetting its roots of early success.

Improving The World’s Most Popular Overdrive? OD-9 Pro+ Overdrive: MSRP $225

The development of the OD-9 Pro+ Overdrive came about by Maxon enlisting an advisory board of professional guitarists who were already well-tuned into the uses and applications of the famous Tube Screamer overdrive. The original OD-9 circuit was used as the base, but for the Pro+ an additional Op-Amp was placed in the output stage to prove a more open and less compressed drive when used in regular drive mode to offer a more balanced frequency response. According to Maxon, the increased output level and true undistorted signal at zero on the drive control are benefits of this p articular Op Amp.

The basic controls on the OD-9Pro+ will be familiar to most guitarists, but the switchable boost feature is new. It bumps up both the midrange as well as the drive level to create a thicker tone that is more compressed and delivers increased sustain.

In use, with the drive control set aggressively and with the boost mode on, the OD-9 Pro+ is ideal against an amp set clean and performed admirably for lead voicings that sang. It’s definitely in the vein of the beloved Tube Screamer here. The mid voicing is very much an “in your face” vocal-like setting where blues rockers often like to be. With the boost off and lighter overdrive voicings selected, the pedal is more reminiscent of a Fender blackface set on mild to moderate overdrive breakup. The tone control is useful with the OD-9 Pro+ and helps compensate for overly bright amps or guitars to help you find your tonal “sweet spot”.

The OD-9 Pro+ has another unusual trick within its circuitry. An internal dip switch, which is accessed under the battery cover, provides a selection of 9 or 18 volts operation through an on-board DC voltage-doubling circuit. When we bumped the 9v signal to 18v, the overdrive and guitar voicing became bigger, more dynamic and generally more open. For those that want a more compressed sound of a typical Tube Screamer, 9v is your setting. However, there’s a lot to explore when engaging the 18v setting. There’s definitely magic within the 18 volt setting and one gets the sense that this is where the pedal should be set to take advantage of the wider frequency range and stronger punch available.

Like Maxon’s other pedals in the series, the OD-9 Pro+ uses a true mechanical bypass 4DPT switch. Unlike many other true-bypass switches that use heavy toggles that “click”, the Maxon design is silent and smooth.

Two Classics Return with a New Name: OOD-9 Organic Overdrive and OSD-9 Overdrive/Soft Distortion: MSRP $260


Before there was the legendary OD808 overdrive, there was the OD880, a lighter gained overdrive unit that was among the most popular in Japan. It offered great dynamic response to a player’s touch and with a mild bit of mid emphasis in the circuit, delivered a creamy overdrive that was pleasant to the ears and fun to play through. With controls simply for drive and volume, the OD880 was as basic of a pedal as you could ask for, but it did its job and earned a spot on many happy guitarists pedalboards.

Maxon’s OOD-9 and OSD-9 are both based on the OD880 circuit but the OOD-9 uses a JRC 4558D Op-Amp, the same found in the majority of the most coveted Tube Screamer OSD9-1overdrives, while the OSD-9 uses the 741-based IC design of the original OD880. The differences in the units are subtle, but clear.

The OOD-9 has its tonal emphasis in the lower mids and feels thicker when the overdrive is pushed. The OSD-9 is more neutral and even in frequencies. Both units have some high frequency cut-off that inherently make them feel warm, and this is probably very likely designed this way originally to compensate for the overly bright guitars and amplifiers offered at the time. I actually found these pedals to be a great match for when I wanted to use them with a Fender amp with its bright switch turned on. With the brightness on and a bit of tweaking to the amp’s tone controls, a surprisingly contemporary overdrive tone can result that has an aggressive, yet smooth edge on the top end. The Fender bright switch allows for a very chimey tone for cleans, but it’s not often that you can mix an overdrive or distortion pedal successfully when engaging it. These new Maxons however work well in this environment.

Running either pedal with the bright switch on the amp turned off resulted in more classic bluesier tones, again, with a little bit of the highs rolled off.

Perhaps where either pedal shined the most was when used as a boost, setting the level control on the pedal to max and the drive control to a minimum. Pummeling a good tube amp in this way always brings out the best in it – the tubes compress and add warmth on the bottom end and the gain structure of the amp becomes dramatically stronger. Because neither of the OD880-based pedals have excessive treble emphasis, they felt especially suited in the role of becoming a boost, and our Fender Super Reverb responded without any harsh, spikiness that can often occur with boosts that may have more high-frequency emphasis.

Our Favorite Analog Delay Circuit Improved: AD-9 Pro, MSRP $375

We’ve always been fans of the old AD-9 delay from Maxon (in either Maxon or Ibanez brand, they were the same) as well as the Boss DM-2. It could be argued that the AD-9 was always a little bit warmer and had the softer decay of repeats that put it just ever so slightly ahead of the old Boss. Our complaints with these units was just if we could only get “just a little bit more” delay time out of them for more spacey effects, they’d be perfect.

Maxon’s AD-9 reissue has been out for sometime, but now they’ve developed the new AD-9 Pro model which improves on the AD-9 by providing longer delay times, lower noise, and a new multi-head tape echo simulator function. Where the old AD-9 could get 300 ms of delay, the new AD-9 pro delivers 450 ms. It may not seem like much, but you can feel the difference when you go for the longer delay time. The dreamy background delays at 450 ms were perfect for space-rock solo lines.

Besides the basic controls for Delay Time, Level, and Blend, a new switch also onboard the AD-9 Pro takes any delay that you set and adds another to it which acts as a second delay set roughly at 50 ms ap art and performs as if you had a second tape delay head. The effect becomes very much like a ping pong repeat, but the ping pong effect can be delivered early (with less delay) or at the 450 ms point (max delay). In this way, the effect helps break up the predictability of single repeats and provides a much richer atmosphere. We loved this new feature of the AD-9 Pro.

With pure analog circuitry, companding noise reduction system, delay times up to 450 ms, versatile multi-head delay feature, and true bypass, all placed in its classic and small 9-series enclosure, the Maxon AD-9 Pro is clearly our new favorite delay unit available and definitely worth checking out.

For information on this series of effects, visit

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