Log in
Log in

Create an account

Add this product to
  • My former gear
  • My current gear
  • My wishlist
Positive Grid Bias FX

Review Positive Grid Bias FX

Written test
1 comment
A review of Positive Grid Bias FX Professional modeling plug-in Amps and Effects on the Grid
Share this article

The competition in the amp-and-effects modeling market is fierce, and there is no shortage of excellent products. Positive Grid, which established itself on the iOS side with JamUp and JamUp Pro, and then moved into the Mac/PC world with Bias Desktop, now has released Bias FX, an amp and effects modeling application that has versions for both your computer and your iPad, and is mostly the same on both.

The Mac/PC edition of Bias FX comes in two versions, which have the same GUI, but different amounts of amps and effects: Bias FX Desktop and Bias FX Professional. The Desktop version, like iPad version, comes with 12 amp models 30 effects. Bias FX Professional has 32 amp models and 52 effects. For this review, I’ll be focusing on Bias FX Professional, but other than the number of amps and effects, both Mac/PC versions have the same feature set and GUI. The iOS version is mostly the same, with a few exceptions.


The user interface for all three versions features a graphically depicted signal path across the top half, in which you can add and remove amps and effects, and move them around in the signal chain order. When you click on a component, it becomes selected, and a much larger version of its controls appears in the lower half of the GUI, known as the Control Panel, and that’s where you make adjustments. For the amps, you get a front or top view, depending on where the controls are on the modeled amp.

The amp defaults to the “Head” view, which features parameters Gain, Bass, Middle, Treble, Presence, and Master controls. All the models feature this identical control set, which means in many cases, you’re not getting parameters that exactly match those on the modeled amp. On the other hand, it’s consistent from amp to amp, which is useful for settings comparisons. On at least one of the acoustic amp models, the Gain control is not active.

You can choose between a single amp configuration and a dual one by clicking on the appropriate button in the Signal Path. Dual configurations use a splitter to divide your signal to two separate paths, featuring whatever amps and effects you want. The two signals are then combined before the output in a Mixer module that offers Level, Pan, and Delay. The latter lets you delay either side up to 30 ms, allowing you to get greater stereo width, and it works great.

You can also select the “Cab” option, in which you’ll see a graphic of a cabinet with a mic in front of it. The amps all have matching cabinets, which can be interchanged with the Cabinet Model drop down menu. You get only two mic models: an SM57 (dynamic) and a condenser (C414). You can move the mics side to side and front to back. And can only have one at a time. Contrast this with Native Instrument Guitar Rig, which, when using its Control Room module allows for seven different simultaneous mic types, although you can’t individually position them. IK Multimedia’s AmpliTube 3 lets you put two mics on at a time, position them where you want, and it gives you 16 different mic choices.

I was disappointed in the lack of change in the sound when moving Bias FX’s virtual mic back and forth from the cabinet. I noticed more change moving it side to side than front to back, but the sonic changes were much more subtle than they’d be if you were moving a real mic on a real amp.

An alternate view, Pedalboard View can be selected from a button at the top. It shows you all the same components you had in the other view, but on a virtual pedalboard. The amp (or amps, if you choose a Dual configuration with the Splitter and Mixer modules), are smaller than when expanded for editing in the standard view, and they don’t expand in this view. The effects are shown as larger than in the standard view, however, and can be edited directly, rather than having to select and expand them first. If you want to expand an effect in Pedalboard View, you can doubletap it..

Going global

All the way at the bottom of Bias FX is a thin strip with some key global controls on it. These include Input and Output level knobs, which are important on an amp modeling plug-in to avoid clipping and to maintain good gain staging. A noise gate, also essential on a amp modeler, can be switched in and out, and features Threshold and Decay knobs. It works very efficiently.

You also get a four-band EQ section called Output Setting, which gives you an additional EQ stage at the output. It offers Bass, Middle, High and Resonate. The latter is not explained in the Bias FX online documentation, (which are quite underwhelming in terms of depth), but it appears to add some sort of high-end boost when turned up to the upper half of its setting. Overall, the EQ section is handy for additional tone shaping, although I didn’t find it necessary on most of the amp tones, which sound good without additional equalization.

Lineup the amps

Bias FX Professional’s model collection offers a lot of choices. It’s broken up into five categories: Low Gain, Crunch, Hi Gain, Acoustic and Bass. For both the guitar and bass models, Positive Grid also gives you some of its own models. For a complete list of amp and effects models in both Bias FX Desktop and Bias FX professional, click here.

The Low Gain category features three Fender amp models, all of which I really liked: 59 Tweed Lux (modeled from a ’59 Blues Deluxe), and the 69 Duo Verb (’69 Twin Reverb), ’67 Blackface (’67 Bassman). Here’s an example of the DuoVerb with some digital reverb on it.


Among the other Low Gain amps are PhD Z (Dr. Z Maz 38 Sr), ’94 Match DC (Matchless DC30), and ’66 AC Boost (Vox AC30). The PhD Z was one of my favorites, offering a clean and present sound with the Gain set low, and a nice fat distortion with it set high. On the other hand, the Vox model was underwhelming. It lacked the versatility of sounds that the real amp has, and paled in comparison to the AC30 models in most other amp modelers.

The Crunch category offers two models of Orange amps, British OR30 (Orange AD30) and British Rock 50 (Orange OR50), and while both sound good, the former has more of that big-sounding distorted tone that Orange amps put out. There are two Marshall models in this category: 69 Plexiglass (JCM 800) and Modded Plexi (Marshall JCM 800). Plexiglass gives you nice clean or crunchy tones, and Modded Plexi sounds impressive when cranked. Here’s an example of the Modded Plexi.


In the High Gain category there are eight different models, including 92 Treadplate (Mesa Boogie Triple Rectifier), Modded Mark IIc+ (modded Mesa Boogie Mark IIc+), German Fire (Engl Fireball) 04 Insane 5153 (Peavey 5150), and Ecstasy 101 (Bogner Ecstacy 101). You also get three models created by Positive Grid: High Gain EL34, Insane Satan, and Snake’s Lead 800.

My particular favorites from that bunch were the two Mesa Boogie models, which sound good both with the Gain cranked and with cleaner, low-gain settings. I also really liked Insane 5153 for its high-gain sound. Here’s an example:


The Acoustic category consists of one Positive Grid acoustic simulator, and two acoustic amps. All three sounded good on electric guitar, although the simulator, despite having a pleasing tone, was not as convincing as others I’ve heard. I also tried the acoustic amps on an actual recorded acoustic (tracked DI through a piezo pickup). I got good results going through the model Acoustic Amp, with some EQ from Studio EQ (Manley Massive Passive) and the Digital Reverb pedal. Here’s how it sounded: first just the dry piezo sound and next with Bias FX on.


Then there’s the Bass Amp category, which includes five choices: ’69 Blue Line (Ampeg SVT Blue Line), 700 RB (Gallien-Kruger 700RB), GK800 (Gallien Kruger MB800) Bass 360 (Acoustic 360), and Positive Grid’s own Supra Bass model. The GK800 and the Bass 360 provide nice clean bass amp sounds. The ’69 Blue Line dirties up a little with the Gain up high, and the 700RB and Supra Bass models give you a lot of distortion when cranked.

Here’s an example of a Fender Precision Bass recorded direct. First you’ll hear the dry direct sound. When it repeats, it’s going through the 360 Bass model with the Tube Compressor (Urei 1176) effect on it.


As a whole, I found the amp models sounded excellent. I compared a number of them to similar models in AmpliTube 3 and Guitar Rig, which sounded a tad more authentic — not in terms of how closely they captured the tone of the original amps, but in how much they sounded like unprocessed amps recorded through a mic. They had a more raw quality, whereas the Bias models had a more “finished” tone to them. If you’re going for pure authenticity, you might not like that, but if you’re trying to get good sounding, instantly usable amp tones, you will. Remember that listeners want to hear great sounds, and aren’t judging whether that JCM 800 is exactly accurate to the original.

One small problem I encountered was that the volume levels varied pretty significantly when switching between amp models. In those cases I had to change the controls quite a bit to get a similar volume. I wish PositiveGrid could have balanced the stock settings of the amp models to achieve better parity in volume when switching between them.

One other annoyance was that every time you switch models, the plug-in resets the amp browser back to the Low Gain category. This added an extra step when, say, comparing amps from the High Gain category. Everytime I’d go to switch, I found the browser was back on the Low Gain section, and I had to navigate back to the High Gain section. This doesn’t happen with the effects. The browser stays in the category that you last chose from, which is as it should be.

Foot on the pedal

Bias FX Professional’s effects collection is very impressive. It’s divided into eight different categories, each with multiple effects choices. The categories are: Gate, Comp, Boost, Drive, EQ, Mod, Delay, and Reverb. Effects are either stompbox or rack-processor emulations.

The Gate category has three different noise gate or noise reduction emulations based on pedals from MXR and ISP Technologies. Somewhat surprisingly, the noise gate that’s in the bottom global section of the GUI was much more effective at getting rid of hum and amp noise then the choices in the Gate category.

The Comp category offers seven different choices including models of stompboxes like Red Comp (MXR DynaComp), on which the right hand knob is called “Speed” rather than “Sensitivity, ” which was on the original. Nevertheless, it definitely does a nice job of emulating that classic pedal. There’s also Blue Comp (the Boss CS-3), and the really cool 4K Comp (Keely 4 Knobs Compressor). Add to that emulations of two classic hardware compressors: Tube Compressor (Urei 1176LN) and Studio Comp (Teletronix LA-2A).

Tube Compressor does a decent 1176 impersonation. Like the amp models and some of the effects, it has slightly different controls than the unit it’s modeled from. In this case, it has a Threshold knob, which the real 1176 doesn’t have. This isn’t a criticism, just an observation.

Studio Comp, which like the original LA-2A, can be switched between Compression and Limiting, can really squash your sound if you turn up the peak reduction and the gain. Here’s a rhythm guitar passage through the ’69 DuoVerb model with some digital reverb. It repeats: The first time through Studio Comp is bypassed and the second time it’s on. 


The Boost section offers four different booster types, including Treble boost and a Tube boost. All do a nice job, and I particularly liked the Tube Boost, which is modeled from a Vox v810 pedal. Here’s an example which starts with the PhD Z amp into a digital reverb with the Tube Boost bypassed, and when it repeats, the Tube Boost is on with the gain at around 2 o’clock.


The Drive effects include a who’s who of classic overdrive pedals including 808OD (Ibanez TR808), Guitar Muff (Electro-Harmonix Big Muff Pi), SAB Driver (Fulltone OCD v.4) and the Vintage Fuzz (Dunlop Fuzz Face), among others. PositiveGrid did an excellent job with these effects. I haven’t heard all of the original units, but of the ones I’m familiar with, Bias FX’s models definitely gave the flavor of the original units. The 808OD and SAB Driver, in particular, I found to be very convincing. Here’s an example in which a four-bar passage is repeated twice. The first time is using the Arsenal preset, which features dual Plexiglass (Marshall Plexi) amp models. When it repeats, it’s going through the same setup but with the SAB Driver on.


In the Mod category, you get a huge amount of choices including Tremolo (Dunlop Tremolo); Orange Phaser, a spot on version of the classic MXR Phase 90; Octaver (Electro-Harmonix Micro Pog); Flanger (Electro-Harmonix Electric Mistress); Uni-Vibe; Analog Phaser (Moog Moogerfooger MF-103 phaser), and that’s not all. Here’s an example that uses the ’77 Silvertone amp model (Roland JC-120) with PositiveGrid’s own Stereo Chorus “rack” unit effect along with Red Comp (MXR DynaComp).


Also included are Cry Wah (Dunlop GCB95 Crybaby) and Pitch Shift (DigiTech Whammy 4). But strangely enough, there’s no way to control the pedals on those units, other than manually with the mouse (which is pretty tough to do while you’re playing), because, at least at the moment, Bias FX has no MIDI learn features, and no automation. According to a Positive Grid spokesperson, the company has such features “in development, ” but they couldn’t specify a timeframe for when they’ll be added. To me, these features are pretty important, and should not have been left out of the initial release.

The Delay category has seven entries, including an Analog Delay (Boss DM-3), Tape Delay Unit (Roland Space Echo), Echotape (EchoPlex), Positive Grid’s own Ping Pong and Reverse Delay modules, Deluxe Delay (Electro-Harmonix Memory Man), and Digital Delay (Boss DD-3). Overall, it’s a very nice selection, giving you just about every type of delay sound imaginable. Here’s an example of some chords through the amp model PhDZ and into the Echotape delay unit. 


Rounding out the effects is the reverb section, and again, you get a lot of variety. Digital Reverb (Boss RV-3), ’63 Spring Reverb (Fender spring reverb outboard unit), Ambient Reverb (DigiTech Supernatural Ambient Stereo Reverb Pedal), Dual Spring (Pete’s Place Audio RCM-2R Dual Spring Tube Reverb), and Stereo Reverb from Positive Grid.

I liked them all. The Dual Spring unit sounded very cool, but was a little hard to set because it has no mix control. That’s an instance where adding a control that wasn’t on the original unit would have been a good thing.

I was also quite enamored with the Stereo Reverb, because you can use it to create some very nice stereo guitar sounds. Here’s an example that uses a slightly tweaked version of the Folk 3 preset, which features one of the acoustic amp simulations.


It’s in the cloud

The number of presets that come with Bias FX Professional is just 34. With all the amps and effects, I was expecting to find a lot more. However, you can access plenty of user-created presets via the ToneCloud feature.

Once you register, you can access ToneCloud from within the plug-in. It opens a window with lists of presets grouped by musical style and showing the components used to create it (you can also set it to show you the latest uploaded and the most popular). Here’s the really cool part: you can audition it before you download it, by clicking the preview button. When you do, it temporarily makes the preset active in the plug-in, and you can play your guitar through it, or hit play on your DAW to hear how it sounds. If you like it, just press the download button.

There are lots of presets to choose from, and the quality is generally pretty good, considering these are uncurated presets uploaded by users. You can also comment on presets you try, which is helpful for others browsing.

The iOS version has “artist pedalboards, ” which are settings from such players as Stephen Carpenter of the Deftones, Niel Zaza and others, which are available through ToneCloud. As of now they’re not implemented with the Mac/PC versions of Bias FX, although according to Positive Grid, they’re due to be added as of the week of July 17.

One interesting thing I discovered. If you download a preset from ToneCloud that has a component in it that’s not included in your version of Bias FX (such as an amp or effect from the Professional version that’s not in the Desktop or iOS version) it will successfully load to your device and you can use it in that preset. You can even edit that preset and save it under another name. While you can’t call up that amp from the regular menu, you can copy the preset, add more components, and keep using it. There don’t seem to be that many user presets on ToneCloud that feature the models that are exclusive to the Professional version, but the potential is there.

While on the subject of the iOS version, I was a bit surprised that there wasn’t more integration between the iOS and Mac/PC versions of Bias FX. When you log into ToneCloud, you should be able to sync up your preset collection between your two devices. You can sync the presets you’ve uploaded to ToneCloud, but your User Bank of presets doesn’t sync.

Tweak that amp

For those of you who like to tinker with circuitry, change tube types, and otherwise tweak your amp models, a separate purchase of the Bias Desktop application will allow you to tweak your Bias FX models to your heart’s content. I didn’t have a copy of Bias Desktop for my computer to test it with, but I gather that the integration is similar to what you get in iOS between Bias FX and Bias Amp. There, by simply clicking a tab, the amp model you have open in Bias FX opens in Bias Amp for your tweaking pleasure.

The scoop on Bias FX

Overall, Bias FX Professional ($199) offers users a huge range of extremely usable amp and effects models. It certainly holds its own  nicely with its competitors, both in terms of the amount of sonic choices and the sound quality. Bias FX Desktop ($99), although not as flush with models as the Professional version, still has quite a few, and is a very good value for the money.

The amp models sounded really good, and seemed pretty accurate, for the most part. I’m of two minds regarding the generic controls that Positive Grid elected to put on all the amp models. On the one hand they adds nice consistency, but on the other, they don’t match the control set of the original amp in most cases, which, for some users at least, will detract from the experience.

Perhaps the most impressive part of this application is the effects collection, which gives you almost any kind of guitar effect you’d ever want, many of which are modeled on classic stompboxes or hardware.

My biggest problem with either version of Bias FX for Mac and PC is the lack of MIDI learn and automation capabilities. Hopefully, Positive Grid will fulfill its promise to add these features soon. Until you can use an external MIDI controller footpedal with it, Bias FX is essentially useless for live performance. And while it’s certainly got plenty to offer in the studio, not being able to automate parameters is a significant limitation. I would have given Bias FX Professional a higher rating if it weren’t for those missing features. To me, it seems like Bias released the software before it was really ready. Don’t get me wrong, it’s a very good application as is, but it will be significantly better once Positive Grid dots a few “I’s” and crosses a few “T’s.


  • Lots of "plug and play" amp sounds
  • Single and dual signal paths
  • Large and very well done effects collection
  • Audition patches directly from ToneCloud
  • ToneCloud lets you access user presets
  • Integration with BIAS Desktop
  • Single and Dual amp configurations
  • Mixer with delay function on dual configs
  • Very similar to iOS version
  • No MIDI learn, so no way to control pedals in real time
  • No automation of parameters
  • Moving microphone model has very little effect
  • Documentation very skimpy
  • Amp browser changes back to Low Gain every time
  • Only 34 presets included
  • Uneven volume settings between models
  • gmeades 1 post
    New AFfiliate
    Posted on 06/12/2020 at 20:31:32
    The Link to the list of all BIAS Amps and Effects goes to a page that says "You're not authorized to access this page" when "click here" is clicked on.

Would you like to comment this article?

Log in
Become a member