Neo Instruments – Ventilator II REVIEW

A Leslie rotary simulator may sound like something that should be used exclusively with a Hammond organ, but guitar players have long jumped on board, and for us bass players, there are a couple of very good reasons to take a much deeper look into this territory as well…

One of the significant ‘organ-related’ sounds that spring to mind in a bass context is Roscoe Beck’s characteristic tone when plying chords and root notes simultaneously, adding some rather heavy chorus to emulate a rotating Leslie sound. You can hear the concept and sound I am talking about in this video. It’s the song You Cut Me to the Bone from a concert with guitarist, Robben Ford, and drummer, Tom Brechtlein. It’s a great performance from beginning to end, but if you are in a hurry, fast forward to around 3:40 where you can see and hear how Roscoe Beck backs Robben Ford the ‘organ way’.



neo-instruments-ventilator-2-control-knobsThe Ventilator II offers 5 knobs, 3 footswitches and 3 LED indicators on the top panel surface. Each of the knobs have a primary function and a secondary function, which causes this section to be expanded a bit… If you are familiar with keyboards / synthesizers or digital outboard equipment, this function is equivalent to the ‘shift’ level many digital units have. You access the ‘shift’ mode by pressing the BYPASS and SLOW/FAST footswitches simultaneously.

The first knob from the left is FAST SPEED and SLOW SPEED (shift mode). As expected, this knob sets the speed targets when you stomp on the SLOW/FAST footswitch. The next knob controls BALANCE and ACCELERATION (shift mode). The Ventilator II actually has two simulators going on. Just like on a real Leslie, the low rotator and the horn rotator works independently, and the BALANCE knob simply allows you to favor one above the other. When in shift mode, this knob sets sets the acceleration for when you switch between slow and fast rotation.

The third and middle knob allows you to add DRIVE, or when in shift mode, it lets you choose between GIT and KEY mode that are different in terms of the frequency response with GIT having the Leslie 122 cabinet simulation off and KEY having it on.

The fourth knob is named MIX/DIST LO and blends your clean signal and the lower rotator simulation, while also relating to the simulated distance of the microphone. In shift mode, this knob allows you to set REMOTE control option.

The last knob does the exact same as the previous one, but for the horn rotary, hence the name MIX/DIST HI. When in shift mode, you can set the overall master output level of the pedal.



white headphone with rhythm symbol

There are 5 rounds of sound clips in this review:

  • Slow
  • Fast
  • Acceleration
  • Drive
  • Various settings


NOTE! Please use headphones or ‘real’ speakers. You simply can’t judge low-end material on laptop, tablet or phone speakers…!

NOTE! If you are on a mobile device, please turn it to landscape mode to see the knob settings of the pedal for each audio clip.





This pedal is wildly versatile. It is the tweakheads dream with super detailed control over just about any parameter you could ever wish for. Having said that, though, there are some limitations to the user interface that makes this amount of control less than intuitive. But then again, tweakheads usually prefer absolute control over intuitiveness. The shift mode is necessary to offer this type of versatility, but it also means that the physical knob positions will only reflect half the story. More on this on the next section.

As you can hear in the sound clip sections, this pedal is a rotary beast, but it is also a great-sounding pedal when you want it to substitute for more conventional modulation effects, such as chorus, flanger or phaser. Not that it sounds like that exactly, but it can be set up to serve the same kind of ‘musical function’ or feel and vibe if you will. For instance, it can easily add subtle, pleasant shimmer to a solo bass part with overtones.

It should also be stressed that the versatility dimension also covers the fact that you not only have immense control over the sound, but also how the pedal behaves in terms of for instance latching modes. This does involve the manual and some LED signal decoding, but it is something you would most likely only have to do once.



The quality seems right up there with the very best. It’s quite heavy (not that it is automatically a sign of quality), and the overall first impression is that it would survive most world tours and types of boots stomping it. The knobs are firm and all connectors feel solid.

As for the design, I have already touched upon certain sides of it in the Control and Versatility sections, but to wrap up the design decision to have a shift level, I actually see it as a good compromise. The alternative would probably have been a set of dip switches only accessible by removing screws. The REMOTE and MODE functionalities could have been handled this way, but the SLOW SPEED, ACCELERATION and LEVEL are crucial parameters to have access to in an easier way.

In fact, I would have preferred to have ACCELERATION and BALANCE reversed, as the balance between the lower and horn rotator emulations is probably a set-and-forget parameter for most, while the acceleration would be great to have direct access to at all times. One thing is setting the general acceleration time, which in my case would be somewhere in the middle, but the one other setting I find very useful is an ultra-short acceleration time where you can go almost instantly from slow to fast and vice versa – even for emphasizing individual notes.

One final thing to mention is that the Ventilator II should be powered by 12V. However, it comes with its own dedicated power supply as part of the package, and today many multi-out power supply units offer one or two 12V or 18V outputs, as 9V is no longer the only standard around. So at the end of the day, this is not an issue, but I felt it should be mentioned in case it would influence your ‘power chain’ structure.



Today (2016), a new Ventilator II is available at $499. That is a lot of money for any pedal, but it does give a zero-compromise solution on tone as well as functionality, which is bound to come at a certain cost. Even considering the fairly high price tag, I would say that there is decent value for money to be found here. Also, consider if it might be able to replace a couple of your traditional modulation pedals to justify the investment.



If you are looking for this particular type of sound, you should definitely consider the Neo Instruments Ventilator II. It gives you total control and an amazing Leslie rotary sound. The only drawbacks are the fairly big footprint (and maybe the weight if you have a big board) and the price tag. Not that the price is too high, as this kind of versatility and quality is expected to come at a cost.



Sounds amazing

Very high quality

Super versatile

Decent value for money



A few key control parameters ‘hidden’ in the shift mode

Fairly big (and heavy)











Find the Best Price




Leave a Reply

Your email address will not be published. Required fields are marked *