BIAS Desktop

This week has seen the arrival of something I’ve been eagerly anticipating for awhile: Positive Grid’s BIAS Desktop. Put simply, BIAS Desktop is the most powerful amp and cabinet simulator I’ve seen or heard. It’s more than just a deep, powerful simulation, it actually sounds great too!

BIAS was originally created for iOS and the same basic premise of that app (top-notch amp and cabinet simulation) has been ported to the desktop version. But on the desktop BIAS doesn’t run as a stand-alone application. Instead it’s built as an audio plugin in many popular formats (AU, VST, RTAS and AAX), so it’s accessed inside of a host DAW application like Logic Pro, Pro Tools or even GarageBand.

Core Competencies

The core of BIAS is its top-notch amp and cabinet simulation. BIAS lets you dig deep into the virtual construction of your amplifier giving you the ability to tweak every imaginable parameter that would otherwise require a soldering-iron in the real world. This feature alone sets BIAS apart from just about anything else I’ve seen.

BIAS comes with a great set of presets to get you started

BIAS comes with a great set of presets to get you started

Out of the box, BIAS comes with a nice set of default presets grouped into different categories like “Clean”, “Blues”, “Crunch”, “Metal” and so on. These are all great starting points for getting a tone that’s close to what you’re looking for. From there you can dive into every component of the signal path (preamp, tone-stack, power-stage, rectifier) and tweak to your heart’s content. You can learn more about how this works on Positive Grid’s YouTube channel (my oh my, who is that handsome fellow doing the demos?)


Positive Grid has built a service called Tone Cloud that allows people to share their patches for free. Looking for a killer SRV tone? Just open up the ToneCloud tab, search for “SRV” and you’ll probably end up with about a dozen results. Since the patches are crowd-sourced, some are a little better than others, but just like the factory presets, these can make great springboards for further tweaking.

A quick search for “SRV” yields over a dozen community-sourced results

A quick search for “SRV” yields over a dozen community-sourced results

Unlike Pod Farm or Amplitube, BIAS is just focused on amp and cabinet simulation. While it does provide some ambient room settings and a noise gate, you won’t find a full selection of virtual effects pedals here. Honestly, that’s okay. I’m a big fan of single-purpose tools that do one or two things really well instead spreading itself wide with a thin layer of mediocrity. The fact that BIAS is focused solely on great amp simulation means the engineering team is focused on making the most crucial part of your tone (aside from your fingers) as good as it can be.

Since audio plugins can be stacked in any DAW it’s no problem to combine the amp tones from BIAS with other effects, even other guitar amp simulation plugins. While I find most of Logic Pro’s amp simulators unusable, the effects pedals sound pretty good and are easy to use with BIAS amp tones.

Amp Matching

One of the most ambitious features in BIAS is called “Amp Matching”. It samples an existing amp tone and applies changes to a BIAS preset to match the live sound. So let’s say you have a Marshall JCM-800 that just screams. Maybe you can only get its killer tone when the tubes are red-hot. We can’t all blast out family and neighbors in the middle of the night, so Amp Matching will let you capture that great tone for later use with nothing more than your DAW, a guitar and some headphones.

Amp Matching only works as well as the source material you give it. First, you need to start with a preset that is close to your amp’s sound. Choosing a shimmering clean preset and then forcing it to match a balls-out 5150 is not going to give you the results you’re looking for (though that might be an interesting experiment).

Secondly, putting a mic on a guitar cabinet takes some time and attention. Guitarists are often surprised at how different an amp sounds with a mic compared to what they hear in the room. Big-budget professional recordings can spend quite a bit of time on mic selection, room configuration and mic placement to get the guitar tones to be just so.

All of which is to say that Amp Matching isn’t a miracle worker, but it is an impressive feature and could be a very handy way to catalog all of your live amp sounds digitally. If you can only get that killer tone by cranking up a live Fender Twin Reverb, “bottling” it in BIAS could be a great way to replicate the tone and still be able to play and record with it without waking up your family or the neighbors in the middle of the night.


BIAS is an impressive feat of engineering. While the iOS version is “expensive” by iOS standards (meaning it costs a few cups of coffee), the desktop version is more in line with professional desktop plugins. Is it worth it? In my book, yes. There’s nothing else like it on the market. To my ears, the amp tones are better than anything else out there. Having the ability to capture your own amps’ tone is icing on the cake.

While I can use my Mesa CabClone for recording the amps I have, BIAS gives me access to amps I’ll never own and it does a damn fine job making me think I’m playing the real thing.