GreenMachine Amp II

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Check out this cool little software amp simulator from Wurr Audio Engineering.

In the heat of the recent "amp modeling" wars, which started in the hardware realm has begun moving to the software arena. Wurr Audio Engineering like many others, has introduced a software based modeler to the market. It's entry is known as GreenMachine Amp which, unlike many software modelers, sits in a comfortable price range of $89.00 USD. Very modest compared to many of it's competitors, which often charge several hundred for their packages.

On November 6th they released R1.1 for the second generation of GreenMachine, logically named GreenMachine II. The R1.1 release cleared up some bugs with unregistered versions compatability with some VST hosts as well as some minor GUI changes.

System Requirements


  • PIII 500mHz processor
  • 800x600 video resolution
  • Windows 98, ME or XP
  • The sound has to be at least 16-bit/44.1 sample rate.


  • P4 or AMD Athlon XP
  • 1024x768 video resolution
  • Windows XP

GreenMachine II is a VST plugin, and therefore requires a VST host to use it, and preferably ASIO drivers for the best performance for real time processing.


GreenMachine II is a VSTi, as such, it's a small download and the install is pretty straight theory. In practice I had some problems as GreenMachine II installs itself into a subdirectory of the systems default vst folder, which is generally c:Program FilesSteinbergvstplugsGreenMachineII or something like that. In some cases (as was my case with Sonar) you need to move the .dll file out of that folder and into the parent, or, the vst root. This issue caused me some problems with Sonar's VST adapter and WaveLab, as neither would start as it was choking on that dll.

After that mess was worked out, I had quite a hard time getting any sound out of it, much due to signal pathing or gain staging on my part, but, considering my level of experience in the field, if I had problems, odds are others do as well, perhaps some tutorials or better documentation would be nice.


GreenMachine II come with two basic preamp models, American and British style, three different amplifier models: Tube50, Tube100 and SolidState and 3 different "stack" tones and open or closed cabinet simulation and backward reflection cabinet simulation. There is also a mix control for speaker simulation.

After the modeling there is a 5 band EQ that has adjustable range bandwidth and output levels and a 3 band parametric EQ in the post path. Wah wah, delay, chorus, reverb, rotary/vibrato effects are available. There are also 5 VU meters to monitor the gain staging at the most critical points of the signal chain.

There are guitar and bass input selections as well as a bypass if you wish to use it for vocals or synths. It has a noise filter and 80 presets of some very good models that can get you up and running very quickly, at least one is bound to be close to the sound you are looking for. The presets are a very wide range of models for almost any situation and style. Minor tweaking from one close to your desired sound should dial you in quickly.

The Interface

The first picture is the "front face", the picture below that is the "back face". At initial install and looking at the product, I found the front and back thing to be quite "cute", for lack of a better word. However, in use, I found the flipping from front to back quite annoying. While I appreciate a designers thought process in making plugins like this (a few have done it), because it gives it a vintage appearance and a comfortable analog feel, in the usability category I find it troublesome. I would much rather have my plugins be software, not a throwback to hardware, and have all my controls on the front panel.

That said, after getting up and running, my whining about the back and front pretty much ceased, or at least was drown out but fun, laughter and excitement of the product itself. The front face is the primary control surface, and is very easy to understand and get around in. Toggling between preamp models, amp models and speaker configuration is a breeze, and the differences between them are very nice.

When judging modelers, I never judge by accuracy, but by quality. By that, I mean, I can't say that the US preamp model sound just like a US preamp, or that the vintage openback speaker sounded like a vintage openback speaker cabinet. However, what I can say, regardless of the accuracy of the model, the sounds were very good, and the range of sounds that are able to be achieved with the different settings, mixing and matching preamps, amp and speakers, is very impressive.

Control Panels

The "drive" panel of the app has a single US or British preamp model. After that you have an option for a single or dual tube simulation. Each tube has drive and volume control plus a boost switch on each tube. The difference between single and dual tube is pretty stunning, and the boost switch really does. The distortion/overdrive is a bit thin and would be well served with some additional hardware produced distortion, but then, I have not yet found a software produced distortion that in anyway simulates a good hot tube. That said, the distortion on this plug is better than most any software-produced distortion I have heard yet.

The tone stack is a a standard pre with EQ controls as well as bright, presence and shift, The 5 band EQ with range and Q controls can be enabled or disabled according to your needs.

The speaker simulator is probably my personal favorite, as it gives pretty extreme control over the sim. You start out with a basic vintage, modern or lead cab with open or closed back. From there you can tweak the resonance and reflection qualities of your cab and mix to taste. After that you can enable the rotary on your cabinet with speed and depth tweaks and then even set up a simulation of miking your cabinet including the distance the mic is from the cab and the angle at which it is placed and mix that to taste as well.

There are VU meters available to you at various stages of the signal path for nice control of the gain staging.

Built in Effects

The GreenMachine II also comes bundled with a few effects in its arsenal.

  • Delay - Pretty standard delay effect with the usual delay controls, those being feedback, width and damping as well as the speed of the delay and the mix. The sound quality of the delay is nice and clean
  • Chorus - Chorus is clean and distinctive and very spacious. Everything you would expect from a chorus
  • Reverb - Very nice reverb. I very much like the smooth reverb GreenMachine II produces. Also, pleasantly, in standard quality the CPU usage does not add as much as I thought it would, but bounding up to the highest quality tended to jump CPU usage by a few percent. That said, ANY decent reverb does, and GreenMachine II does have a more than decent reverb.
  • Wah - The wah is fun, it's clean and does what it's supposed to do, no more, no less.


The market for software based amp simulators has become quite saturated as of late, everybody is getting into the game, but most are charging astronomical prices for their product.

GreenMachine II is a very high quality amp sim. It offers great control over the tone at all levels of the simulation and bundles in some very nice effects as well, my favorite being the reverb, personally. My only real complaints are the front and back design, as stated earlier, I would rather have all the controls up front. In addition, the installation hassles I previously mentioned were annoying, but not insurmountable.

GreenMachine II also, unlike much of their competition, sells for a more than fair price. $89 is all they are asking for this very creative and functional software amp sim.

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