(3 customer reviews)




Classic Bass Overdrive



GENZLER® AMPLIFICATION proudly announces a “redux collaboration” that brings Jeff Genzler and engineer Andy Field back together again — developing a new line of bass effect pedals under the Genzler Amplification brand.  Both forces have shared design passions that date back to the early 1990’s while working together at Jeff’s previous company, Genz Benz.   Andy, Jeff and current Genzler Amplification principal engineer Scott Andres were responsible for the products that put Genz Benz on the map, so many years ago.  After parting ways after Genz Benz, Andy was soon brought-on at Mesa Boogie to develop their flagship line of Subway bass products.  Eventually Jeff  and his wife Catherine decided to jump back into the game, starting up Genzler Amplification along with Scott Andres as principal engineer.  Jeff and Scott working together again developed such innovative products as the Bass Array cabinet designs, the Magellan series of bass amplification, the Acoustic Array combos, and recently the Nu Classic series bass cabs.

While Andy remains at Mesa designing new Mesa specific products, with the blessings of management there, this new “gig” brings back the fun and collaboration of working closely with good ole’ friends and compadres. “When you’ve worked so long together in the trenches over a few decades, having this team back together just feels good all over again”— Genzler states.  Andy Field comments: “it’s like getting the band back together, again”.

And now, the GENZLER® AMPLIFICATION pedal line will explore a variety of pedal concepts based on their decades of collaboration together, looking back into hundreds of pages of their old design ideas, and to explore interesting circuits that were started but never used, blending them with new innovations.  A retrospective of sorts, this is a chance to dig into their collective pasts to develop what they feel players would use and appreciate, going forward.

The first pedal in the line is the 4 ON THE FLOOR, CLASSIC BASS OVERDRIVE, offering 4 separate “gears” of variable analog overdrive textures and harmonic content to SHIFT through, along with a clean blend feature. HPF and LPF controls are included to shape the overdrive engine’s signal path. This pedal offers touch sensitive asymmetrical and symmetrical overdrive characteristics, variations of compression and overdrive complexity, along with a true bypass.  The versatility allows this to be used as a clean boost, along with the various overdrive gears, up to all out heavy saturated drive.  This pedal also offers another level of versatility as it accepts nearly any power supply; 9 – 18 Volts, either polarity. (Power supply not included).


SKU: 4-OTF-PEDAL Category:


The 4 ON THE FLOOR™ Classic Bass Overdrive is an ALL ANALOG bass overdrive pedal that gracefully emulates 4 different overdrive types found in classic tube circuit topologies and then gives the player additional control over drive/gain, overdrive path (only) with high pass and low pass filters and separately a clean blend. The result is the ability to tailor and fine tune the overdrive to fit with a wide spectrum of music and playing techniques, without the loss of touch sensitivity, musicality, or the addition of induced excess noise.  This versatile pedal can be used as a clean boost, an “always on” tonal enhancement, or offering varied overdrive textures to shift through, for selected performance requirements.

Drive Select “Gear” Descriptions:

1st GEAR: Reminiscent of a tube amp’s clean channel (including natural harmonics) with a bit of overdriven tone when driven hard. A nice “always-on” selection.

2nd GEAR: Emulates a tube amp’s mildly overdriven tone, with a small amount of dynamically compliant clipping asymmetry. This is a natural feeling, touch sensitive algorithm with very mild compression that responds with more texture and complexity, the harder you dig in.

3rd GEAR: A more aggressive up-shift from 2nd gear, this moderate, asymmetrical overdrive is less compliant, with greater compression for a tighter feel.

4th GEAR: This is the most aggressive gear of all — a heavier, symmetrical, low compliance overdrive that can enter distortion territory when driven hard. While there are a lot of harmonics and compression present, this gear does not give up tone or feel.

With the versatility in overdrive algorithms and tonal options, the 4-OTF-PEDAL is an excellent compliment to either of our MAGELLAN 350 or MAGELLAN 800 bass amps.


    • Lightweight Aluminum Chassis
    • Rugged Stomp Switches
    • Low-noise, Silent Switching Circuitry
    • 4 Position Overdrive “Gear” Selector Switch
    • High-Pass and Low-Pass Filters (Overdrive Engine Only)
    • Parallel Clean Signal Path
    • High/Low Drive Sensitivity Switch
    • Accepts Power Supplies From 9VDC – 18VDC (low noise type), Either Polarity (auto detecting) 40mA Max — (Power Supply Not Included)
    • Dimensions: 5”W X 4.1”D X 2.3”H
    • Weight: 1 Lbs.

Additional information

Weight 2 lbs
Dimensions 7 × 5 × 8 in



Genzler Amplification


  • Power Supply: 9VDC-18VDC (low noise type), either polarity (auto-detecting), 40mA max (Power supply not included).
  • Input Impedance: >1M ohm
  • Output Impedance: 1k ohm
  • Overdrive Engine Input HPF: 30Hz – 200hz
  • Overdrive Engine Output LPF: 1kHz – 14kHz
  • Input Sensitivity (nominal): -20dBu (high sensitivity), -10dBu (low sensitivity)
  • Maximum Input Level: 0dBu (9V supply), +5dBu (12V supply), +10dBu (18V supply), high sensitivity, DRIVE at 9:00
  • Maximum Input Level: +5dBu (9V supply), +12dBu (12V supply), +18dBu (18V supply), low sensitivity, DRIVE at 9:00
  • Maximum Output Level: +9dBu (9V supply) +14dBu (12V supply), +20dBu (18V supply)
  • Dimensions: 5” (127mm) W x 4.1” (104mm )D x 2.3” (59mm)H
  • Weight: 1.1 lb (0.5kg)

Owner's Manual

Click to View Owner’s Manual

Video Demonstrations



Andy Irvine:


Bass Gear Magazine




Gregor Fris

ReQ + 4 On The Floor

Media Reviews

Bass Gear Magazine:



Bass Gear Magazine


  1. Tyler Wadsworth

    This is a workhorse of a pedal. There are SO MANY ways to adjust the type and degree of OD, from just a subtle touch through full on distortion/fuzz.

    I’ve been looking for the right OD pedal for a while. The ones I’d tried in the past were just not doing it for me. Too buzzy, too artificial sounding, not as sensitive to dynamics as I wanted, or for other reasons just not what I was looking for. I stopped looking for a while, as I was getting a good bit of what I want from pushing the gain on my Mesa WD-800, but there were times when I wanted some different flavors of dirt.

    This thing can burn rubber in all 4 gears! Each gear gives a little different flavor and intensity of OD. The amount of drive in the signal can be manipulated by the Gear selected, Drive control, and Drive Volume. Changing the relative levels of Drive Volume/Clean Volume or adjusting the Drive Control give different ways to determine just how much OD is applied to the signal. An additional way to further adjust the amount of OD is the option to use the Drive Sensitivity switch. My basses are fairly hot, so I’m finding plenty of drive in the low sensitivity setting.

    1st gear is the mildest/lightest amount of drive, but it does get into some nice OD with the Drive turned up some. 2nd gear starts where 1st gear leaves off, and provides a higher amount of OD and a little compression. So far, 3rd gear might be my favorite. It’s the kind of OD that really compliments what I can get out of the preamp of my WD-800 when I push the gain. There’s some nice compression, enough that it dispaced my trusty Markbass Compressore on my board. (I mostly used that for the tube compression and warmth it added to my signal. I think I’m going to get that out of the 4OTF.) But if I want to max it out, I turn the sensitivity to high, throw it up into 4th, and step on the Drive to 3:00 and it is just fuzztastic!

    There is a HPF that controls how much of the raw signal input is fed into the OD circuit, and a LPF just before the output, which can dial out some harshness. These allow even more control of the amount and flavor of OD. I’m just beginning to experiment with adjusting those to even further manipulate the tones coming out of this pedal.

    One of the things I’m really loving about this pedal is the abililty to fine tune the degree and type of OD. It sounds really sweet with the WD. I’ve mostly been playing it with the amp gain set fairly low to let the 4OTF do all the OD, but when I push the gain on the WD, I’m finding even more options to tweak my tone. The WD is famously pedal-friendly, and it’s no surprise that a pedal that was developed by its designer complements it so well.

    I got the 4OTF from Music Makers on Reverb for $229.99 with free shipping. Great buying experience, it arrived a day early, extremely well-packaged in a larger outer box than I expected, well-protected with lots of foam peanuts. The manufacturer’s box it came in is sturdy and there’s plenty of protection in the box. The manual is well-written and straightforward. I’m running it with an 18v power supply. It can run on 9-18v, center + or -, so it is very versatile with regard to power supply requirements. It’s dead quiet. And it can be used for clean boost as well.

    The Genzler 4 on the Floor is a LOT of pedal for a very reasonable price. With such a great range of usable tones, it is going to slake the OD thirst for a lot of players!

  2. Tim

    Fantastic Bass OD Pedal!
    This all analog pedal produces some fantastic OD sounds. Very easy to dial in just the right amount. HP and LP filters along with clean blend ensures the lows stays really tight and the highs don’t get to distorted. Changes between OD gears are subtle but apparent. I love how all gears one through four produce usable tones and the OD tones only gets extreme when cranking the gain towards it’s limit. If I want a more extreme OD I run a clean boost in in front (spark pedal- full size) and it works great. Pedal pairs nicely with my passive and active basses. I’ve had the pedal for a couple of weeks now and i’ve let go of a couple of other OD pedals in favor of this one.

  3. Donnie G.

    Perfect for what I wanted! In decades of playing I mostly thought bass distortion sounded silly and fake, thus no interest. But overdrive is another matter and alternative to the fake buzzsaw some pedals produce. I wanted a little breakup to fill in and add some character. I’m using all tube Ampeg 100w heads, but pushing them to compression and breakup is too loud, but does sound good. This is a perfect alternative. Great (four actually) versions of overdrive in one box. I’ve used it a couple weeks and am still learning, but have been able to get great tone without a lot of knob turning. I love this pedal and only wish I thought to get one sooner. I expected to find this pedal to be just OK, but am really impressed at the natural sounding breakup and overdrive. And the breakup is part of the tone (while not destroying your tone), nor does it sound like overdrive being layered on top of tour signal. It will do distortion/fuzz if cranked, but that is way more than I need or want. My drive is around 2:00 to on occasion near 3:00 for really weak output basses. This pedal is very flexible. Ideal for someone who doesn’t want buzzsaw but does like when a tube amp is pushed getting into compression and break up.

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