Maxon OD9 Overdrive

Maxon OD9 Overdrive Pedal

While the OD808 may have been the first overdrive circuit of its kind, it was the Maxon OD9 that cemented this sound in the history of Rock & Roll guitar.

• Maxon’s version of classic TS-9 Tube Screamer
• More Drive and Output than OD808
• NJM (JRC) 4558 Op Amp
• True Bypass Switching
• The tone that made Stevie Ray Vaughan famous

OD 9 original circuit

Looking at the OD9’s circuit, you’ll realise this is the original, not a redesign with some clever marketing

It is the OD9 (TS-9) circuit, yet with the addition of true bypass switching.

Even the PC board is the same one that Maxon’s been using for the past 30+ years, complete with empty slots where parts for the FET switching circuit have been left out!

Original components

Like the original, the current production OD9 features the NJM (JRC) 4558D Op Amp – an essential component for authentic “TS” tone.

The NJM is smoother sounding and less compressed than other Op Amps, offering superior sound quality with low noise.

The absence of the FET switching circuit gives the OD-9 some added output and a slightly more open sound than the OD808, making it perfect for the classic rock tones that it helped to define.

If your future plans include a meteoric rise to rock & roll stardom, then rely on the legendary tones of the OD-9 to fuel your ascent.

The Maxon OD9 is a true-to-spec reissue of the legendary 1980’s OD-9/TS-9 circuit, with the addition of true bypass switching for clean, uncolored tone when bypassed.

TECH TALK:

Input is fed into a 2SC1815 emitter/follower transistor to optimize the signal’s impedance structure.  From here it’s on to the first section of an NJM 4558D Op Amp.

NJM is the company formerly known as the Japan Radio Corporation (JRC). The legendary manufacturer that designed and built tons of these components in the late 70’s/early 80’s.

In this non-inverting Op Amp there are diodes in the feedback loop that clip the signal gradually.

It is also a High-Pass filter that keeps low frequencies from being distorted as much as high frequencies. This is the classic “808” configuration that creates the tone we all know and love.

After this is a passive LP filter and then an active tone stage. This uses the other half of the Op Amp to create a HP filter that brings back frequencies cut by the inter-stage LP filter.  After the tone stage, it’s through the volume pot, another E/F 2SC1815. This provides a low impedance output and then the true bypass switch.

Maxon 0D9  Features

• Mechanical True Bypass switching via a Fujisoku 4PDT switch – input signal is sent to ground when bypassed.
• 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: -114 dB or less (input shorted IHF-A weighted)
• Maximum Output Level: 0 dBm
• Maximum Gain: +40 dB (at 1.5 KHz)
• Controls: Drive, Tone, Level
• 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: 6 mA (9 V) / 7 mA (10 V)
• Dimensions (whole): 74 mm (W) x 124 mm (D) x 54 mm (H)
• Weight: 580 g
• Full features manual
• Accessories: 9V Manganese dry cell battery (S-006P) x 1