Nine Series Effects Pedals

maxon nine series guitar effects pedalsSince their introduction in the early 1980s, Maxon Nine Series designs have achieved a legendary status with pedal connoisseurs around the globe. The reasons for this are simple - superior sound quality and innovative features that offer a seamless interface between performer and performance. 20 years later this rule still holds true. Now available with improved circuitry including JRC4558 IC chips and True Bypass Switching, Maxon Nine Series effects remain the standard by which all others are judged.

OD-9 Pro Plus Overdrive


More Info

The Nine Series Overdrive Pro+ takes Maxon’s classic OD-9 circuit and serves it up with two side orders of Whoop-Ass in the form of 9/18 volt operation and a Mid Boost switch.

In 9-volt setting the Pro+ sounds and functions like the standard OD-9 with the added option of a healthy +3 dB of midrange boost at approximately 800 Hz (actual frequency is dependent on Control settings) – great for cutting through a band during solos.

When set to 18-volts the OD-9 Pro+ becomes an 800-pound Gorilla, offering up beefier lows, tighter saturation, improved dynamics and a chunky, aggressive pick attack that will make your amp sound and feel like it just took a Viagra.  Switch on the Mid Boost in this mode and let your solos breathe fire.

Don’t just play like the pros – play with the Pro Plus.

Why Choose Maxon?

The OD-9 Pro+ offers all the classic sounds of the original OD-9 as well as additional features that add increased versatility to its performance.

Tech Talk

The OD-9 Pro+ starts with a jFET buffer which simultaneously offers high input impedance and low impedance into the rest of the pedal – this helps to preserve high-end clarity in the signal.

The first tone stage is the Mid Boost feature:  A switchable Op Amp with clipping diodes in the feedback loop.  When this stage is not in the signal path the pedal behaves like a standard OD9.  With this stage in the path it adds subtle gain and definition to the sound, similar to a cascading gain stage.

From here it’s on to the standard OD-9 circuitry:  A clipping Op Amp with diodes in the feedback loop that clip the signal gradually as well as a high pass filter that keep the low frequencies from being distorted as much as high.  Next there comes a passive LP filter and then an active tone stage.  After the tone stage it’s through the Volume pot, an Op Amp boost stage which bumps the signal 3X and then sends it to the output.

The Pro+ also utilizes an NJM2374A voltage conversion chip that changes the 9V power input into 9V+ and 9V-, increasing the headroom of the Op Amps (9V to 18V swing) and giving a bigger, chunkier sound to the overdrive.

The OD-9 Pro+ features Mechanical True Bypass switching via a Fujisoku 4PDT switch - Input is switched to ground when bypassed.

NOTE ON POWERING THE OD-9 Pro+ - this pedal’s voltage regulator IC requires a high inrush current of approximately 2000 mA upon startup.  When using with a Power Brick such as the Voodoo Labs Pedal Power 2+, this pedal should be connected to a high current power jack when possible

If it is not possible to connect to a high current jack, you can power the OD-9 Pro+ by leaving a battery in the pedal.  Upon initial start-up, unplug the external DC power input cable, engage the pedal, and then plug the DC power input cable back in – the pedal will now power up normally off the external power supply until you power down your pedalboard.

Mods & Mends

Classic 808 Mod

Completely Clean Mod

What Artists Say…

Kurt Fraunfelter

Kurt Fraunfelter

Thy Will Be Done

Kurt Fraunfelter"My Maxon OD9 Pro+ makes my amp sound like a monster! It gives me the extra crunch and beef that I need to my tone where it needs to be. Maxon is the original. Why would you use anything else?!?"

Javier Serrano

Javier Serrano

Guitarist with Alex Campos

Javier Serrano"The Maxon OD-9 Pro+ offers the classic, robust and creamy sound that I absolutely must have on my solos - I cannot go onstage without it!"

Eric Lambert

Eric Lambert


Eric Lambert"I can't play through my amp without turning on my Maxon OD-9 Pro+ first - there's simply no comparison without it."

Jeff Cummings

Jeff Cummings

Sworn Enemy

Jeff Cummings"For years I was searching for pedals that would round out my sound and finally I have found that in the OD-9 Pro+ and SM-9 Pro+ my rig doesn't sound complete without them."


od9 pro plus video 01


Pedal Shootout Demo
od9 pro plus video 02


Tone Talk - Episode 6
od9 pro plus video 03

Dave Weiner

Pedal Shootout w/ David J.
od9 pro plus video 04


Suffocation Band - Gear 2012 Maxon Pedals



Input Impedance: 500K Ohms Input Jack: 1/4 inch standard phone jack Output Impedance: 10K Ohms or less Output Jack: 1/4 inch standard phone jack Outputs: 1 Equivalent Input Noise: -116 dB or less (input shorted IHF-A weighted) Maximum Gain: Normal 43 dB (at 1.5 KHz), Boost 46 dB (1 KHz) Controls: Drive, Tone, Level, Boost/Normal switch, 9/18 volt operation switch Switch: Normal/Effect (true bypass configuration) Power Supply: 9V Manganese dry cell battery (6F22) or special AC adaptor Power Voltage: DC9 V (Battery) / DC10 V (AC-adaptor) Current Consumption:
35 mA (9 V) / 32 mA (10 V) at 18 volts
27 mA (9 V) / 27 mA (10 V) at 9 volts
Battery Life:
Manganese Dry Battery approx. 3 hours
Alkaline Dry Battery approx. 8 hours
AC Adaptor: AC210N (option) Input: AC120V Output: DC9V/200 mA Center - / Sleeve +) Dimensions (whole): 74 mm (W) x 124 mm (D) x 54 mm (H) Weight: 580 g Accessories: 9V Manganese dry cell battery (S-006P) x 1 Warranty Card: x 1 User's Manual: x 1 * All specifications are subject to change for improvement without notice or obligation. All brand names and product names are trademarks or registered trademarks of their respective companies.
  • Overdrive based on classic OD-9
  • Switchable 9- or 18-volt operation (runs on 9 VDC)
  • More Gain and Low-End (18-volt setting)
  • Mid Boost Switch add +3 dB @ 800 Hz
  • NJM4558 (JRC) Op Amp
  • True Bypass Switching
guitar world platinum award


Rate This Product
Not Good Fantastic

Captcha Image

Javier commented on 14-Oct-2014 08:50 AM5 out of 5 stars
Having tested and loved the VOP-9 of my band's mate i decided on getting a similar but a bit wilder pedal, the OD9 Pro + seemed to suit my needs based on the description and the internet reviews. I'm so glad I pulled the trigger on this one, it is amazing. The range of overdrive is larger than I expected, it starts from an almost 100% clean sound and goes to lovely wild overdrive. Playing my Strat without it feels strange now to me. It works very well with other pedals and cleans also very, very well wen you play soft or roll your volume pot off. It feels a bit more organic and less hi-fi than the VOP to me but equally smooth, classy and rich all the way from zero drive to max. The VOP9 has a greater volume boost.
I'll never get rid of the OD9 Pro+. Easily the best overdrive I've tried. As always with all the Maxons I've tested the whole range of the sounds available are top quality and utterly usable, like each one is fine tuned prior to shipping.
I should have got it from the start but on the other hand, 20 overdrive pedals or so after, I really appreciate how perfect this gem is.
Frank commented on 19-May-2014 07:32 PM3 out of 5 stars
Love the sound. However the foot switch is terrible.
OD-9 Pro Plus Overdrive
Maxon on Facebook Maxon on Twitter Maxon on MySpace Maxon on YouTube
46 Marlboro Rd., Clifton, NJ 07012
Godlyke Distributing