Plugin Alliance Black Box Analog Designs HG-2 Plugin Review

Publish date:
Social count:


The Black Box Analog Design HG-2 is one of the most widely acclaimed analog processors ever created; it’s a tube-based coloration and saturation unit known for adding richness and depth to full mixes and sounds, while adding punch and glue, and it’s a staple on the mix buss of some of the world’s most respected mix and mastering engineers. The HG-2 is also known for its incredible range of colors and capabilities; it’s multiple tube circuits allow the unit to add slight harmonic enhancement all the way up to brutal saturation and distortion, along with every color in between. Plugin Alliance, a leader in analog modeled digital processors, has released a plugin version of the HG-2 which was developed with Black Box Design; in this review we’ll put it through it’s paces to see if it lives up to the hype of the analog unit.

Buy the Plugin Alliance Black Box Analog Designs HG-2 Plugin at the lowest price on

Setup & First Impressions

All Plugin Alliance plugins are downloaded and authorized using the same system, which is straightforward and easy to get the hang of. PA allows users to authorize hard drives or USB flash drives, which is a nice bit of flexibility many plugin manufacturers don’t offer. Additionally, there’s a fully functional 14-day trial available.

Upon first opening the plugin, it’s immediately clear that this unit offers a wide range of tone shaping capabilities. Large knobs for Pentode and Triode tube saturation are the highlights, but the plugin also offers a parallel tube saturation circuit (with a switchable alternative tube), a frequency saturation selector (Low/Flat/High), an “air” band enhancer as well as input, output, mix, and density (more on this later) controls. Finally, the plugin also models the entirety of the input/output signal path of the original unit, giving you two virtual transformers which make almost anything sound more pleasing.


The pentode and triode knobs are the two you’ll likely use the most with this plugin, as they control the two main tube saturation paths. Pentode tube circuits are renown for their ability to add even order harmonics to a sound, which are very pleasing to the ear. For beginner producer/engineers, it’s important to understand this point: tube circuits are so loved by audio engineers because they add harmonics which are not present in the original signal - this is very different than using an EQ to boost frequencies, as EQ will only boost what is already there. The Pentode circuit is placed in serial with the Triode unit (meaning signal which passes through it is pushed into the Triode tube), creating an interesting effect as you drive the Pentode unit past 50%. Triode saturation produces odd harmonics, which is more typical of overdriven tape circuits; in small doses this can be quite pleasing to the ear, but it’s often used in higher amounts to add considerable grit and edge to a sound.

An unexpected highlight of the plugin is the switchable parallel saturation circuit, which models two distinct 12AX47 tubes; these are known for their clean, modern sound, and can be used to add a lot of clean punch and polish to almost any sound or mix. The parallel circuit is a welcome additon to this plugin, as it really allows for much more modern and clean tones than would be possible without it. The Air enhancer, which expands on the hardware unit with a continuously variable air band, adds shine and additional high frequency polish above 10K.

One of the features of this plugin that is likely to be overlooked is the very useful Density knob, which lives alongside the Mix and Input knobs at the top of the plugin window. Density adjusts the input and output gain simultaneously, essentially maintaining level while allowing you to dial in more or less overdrive and harmonic saturation. This is a great tool for making sure you don’t add too much distortion to single sounds, as well as allowing the user to preview a wide range of harmonic flavors without needing to adjust multiple knobs.

So how’s the sound? Outstanding. I have not been lucky enough to use the HG-2 hardware, so I will try to avoid making comparisons on whether this does or does not sound like the hardware unit, although online reviews of the plugin indicate that many users feel it compares quite well. The plugin is one of, if not the best, in the box saturation options I’ve encountered to date; it can add heaps of saturation and color, even pushing into outright distortion typical of a amp sim or hardware tone pedal, but it also excels at adding shine, polish, and subtle saturation and enhancement to mixes, subgroups, and individual tracks.

I began the demo period of the HG-2 in the middle of a major project I was working on, and I found it to be among my most used plugins as soon as I had gotten my bearings with it. I first used it across my master buss, as the first plugin in my chain, and found that it instantly made the mix far more coherent and tight, taming an unruly low end I had planned to fix in the mix stage and giving a genuine sense of analog depth and width. Even on laptop speakers, there was a clearly audible smoothing of the track (while retaining and in fact enhancing punch), that simply made it sound more like a record that had been mixed with high end outboard gear. I also found it incredibly useful on single sounds and subgroups, adding it to bass, vocals, synths, and keyboards in varying degrees to push them forward in the mix.

This is an outstanding plugin, and well worth the price of admission. Although it might be monstrously complex (and is achievable using 3rd party tools from vendors such as Blue Cat Audio), I’d absolutely love to see a multi-band version of this plugin; being able to apply variable tube saturation to different frequency bands would make this plugin absolutely indispensable, if it’s not already. 10/10.

Check out our sound examples below - all files are level matched.


  • Outstanding sound. Has much of the ‘weight’ of hardware tubes.
  • Beautifully enhances punch, high frequencies, and low end depending on settings and input levels.
  • Parallel 12AX47 tube circuits (with switchable tube paths) add a distinctly modern and clean tube sound.
  • Flexible - capable of everything from subtle high end polish to full on, guitar-amp level brute distortion.
  • Can apply saturation to different parts of the frequency spectrum, which makes it far more versatile than some rival plugins.


  • None, but a multiband version would be nice.