The Warm Audio WA-412 4-Channel Microphone Preamp is an exciting offering to the pro audio world! Warm Audio is a brand that I have liked for a long time. At my old studio, I used their EQP-WA and 1176 clones often, so I was excited to get my hands on this mic pre-amp! I often recommend Warm Audio gear to friends who are looking for fairly priced, great sounding gear, so my expectations for this preamp were pretty high!

Warm Audio is a relatively new player in the pro audio space, founded in just 2011. In that short time, they’ve become a great option for engineers who want top quality products at prices that don’t totally destroy the bank.
If you’ve been using the stock preamps from your interface, upgrading to a nice outboard preamp is a quick way to improve the sound of your recordings. Let’s dive in to the Warm Audio WA-412 and see what it has to offer!
What are the specs?
The Warm Audio WA-412 is a clone of a famous API preamp, with 4 XLR inputs and outputs, plus a balanced output option. Each channel has phantom power, making it compatible with condenser microphones, and a pad, polarity, and hi-z button. It also has a tone button, which switches the impedance of the signal when engaged. The DI inputs are useful and save you from having to climb around to the back of your rack when recording a 1/4in source.
Warm Audio is not reinventing the wheel with this preamp, but considering it comes in at a price much lower than the preamp that inspired it, that’s to be expected.
How does it sound?
The WA-412 is a great sounding preamp for the price. I don’t have any API preamps around to compare it to, so I won’t be comparing it directly to the API unit. On its own, however, the WA-412 is a nice sounding preamp with plenty of fairly clean gain for any recording application. I’d describe the sound as classic and punchy. It really reminds of the best recordings of the golden ages of rock.
Check out DigitalDrums comparison of the API and Warm Audio preamps to get a feel for how it sounds on various drums!
The WA-412 can certainly introduce some color to your signal, especially when you switch on the tone button. If you’ve used the Slate VMR US A emulation, that is a good comparision for the type of color you can get from the WA-412. Considering both are API emulations, even though one is hardware and one is software, it makes sense that they would share similar tonal characteristics. I didn’t find the tone button to alter the sound in an extreme manner, but it does give a nice subtle change to the tone, more-so when you are really pushing the gain into yellow/soft clipping territory.

Favorite features of the WA-412
I love that the WA-412 has packed some serious tone into a single rack space. To me, something like the Warm Audio WA-412 is much preferred to something like an API Lunchbox or using four separate pre-amps. Having all four preamps in one unit makes setup easier, makes your rig more portable, and keeps you from needing a ton of extra rack space.
I also love that all four DI inputs are on the front of the unit. It makes it super quick to record scratch instruments or keyboards in a flash.
Best Uses for the Warm Audio WA-412
A 4-channel preamp like the WA-412 is especially useful for recording live instruments. For example, if you’re setting up to record a drum kit, a unit like this would be great for your main kick mic, snare mic, and two overheads. Alternately, you could run all of your shell mics though this preamp (kick, snare, two toms). It’s also great for stereo micing an acoustic guitar, or using two mics on an amp.
If you often find yourself recording bands, this is a great way to add some color and punch to your signal chain and improve the sound of your source that’s going into your DAW.
Is the WA-412 for you?
Considering the slim form factor of the WA-412, it’s a great option for someone who wants that analog sound without filling up an entire rack full of preamps. If you’re a bedroom producer with lots of synths you like to keep plugged in, someone who records drums or guitars often, I can’t recommend this preamp enough. Getting four channels of discrete mic preamp for this price, in this small package, is certainly commendable.
If you currently don’t have any external preamps, and have been using your interface’s built in preamps for recording, this is a great option to really step up the tone of your signal. A unit like this will grow with you, as even if you choose to upgrade your interface in the future, this will be compatible with whatever new interface you get. For this reason, I’m a big fan of upgrading external preamps rather than buying moderately better interfaces every time you can afford a slight upgrade.
The Warm Audio WA-412 is not for you if…
If you’re more of a singer-songwriter who realistically only records a channel at a time, there are single channel options that might better suit your needs, like the WA12. If you primarily record vocals, I’d suggest spending your budget on a single-channel preamp that brings more to the table for a similar price. Sure, you’d only have one channel of top tier preamp, but if you’re just recording vocals and acoustic guitars, that’s all you need.
Should I buy the Warm Audio WA-412?
If you’re looking to get a great drum sound, kick your guitar recordings up a notch, or expand your selection of preamps, then the answer is undoubtedly yes. Does it nail the API tone? I can’t say for certain without doing a proper A/B test, but they sound very similar in the Digital Drummer comparision.
I can say that it’s one of the best sounding multi-channel preamps when you consider the dollars per channel ratio, and it would be a great addition to any studio that’s looking to up the quality of their recordings!
If you found this review helpful, feel free to check out the rest of my reviews here!