Review: Warm Audio WA-2A

How does this more wallet-friendly reimagining of the legendary LA-2A Leveling Amplifier compare with UA’s reissue? Simon Allen gets his hands on both…

Well that’s a familiar model name. The excitement around the release of this product at NAMM 2016 was significant; designed to be an affordable replica of the well-known Teletronix LA-2A, I couldn’t be more intrigued to test one. If there were a list of Holy Grail pro-audio equipment, the LA-2A would certainly be up there.

Warm Audio has already made replicas of other famous pieces of audio equipment, such as the EQP-WA Pultec-style tube EQ, the WA76 discrete compressor and WA-12 preamp. It doesn’t take much effort to guess the influence for these devices either.

What’s important for me, however, is that Warm Audio didn’t release the WA-2A first. Now that its other devices have been well received, it should be ready to take on what is one of the ultimate pieces of hardware. The WA-2A is Warm’s most expensive product yet, which is to be expected, but equally the most anticipated.


The WA-2A is a 2U rack-mountable unit, unlike the original’s 3U requirements. While this seems like a convenient space-saving benefit, Warm Audio recommends leaving 1U space above for keeping the unit cool and extending the life of the tubes. I would urge that any new owner thinks carefully if rack mounting the WA-2A as it does indeed get warm. I also assume that the 2U casing is a cost-saving measure.

The front of the device is as you would expect. There’s not much to say here as there isn’t anything the original units do or don’t have. The only addition they’ve made are variable indented potentiometers for the output gain and peak reduction, so that settings can be recalled when mixing. Having up to 40dB of gain on the output almost permits the WA-2A to be used as a mic preamp, or at the least offers another stage of amplification for low sensitivity mics.

On the rear of the unit, besides the XLR and balanced jack connectors, there are three knobs. The pre-emphasis control and meter adjust are two settings the original units would have required a screwdriver to operate and were sometimes found on the front panel. I like the dedicated controls but in my opinion, it does mean access to the rear panel shouldn’t be restricted when installing in a studio. A range of characters can be achieved via the pre-emphasis control, which changes the frequency weighting on the side-chain input to the compressor.

Inside is where all the important decisions were made in order for the unit to stand up against such an icon. Component-wise CineMag input and output transformers were chosen and, true to form, there are four vacuum tubes. Interestingly, you can see through the grille on top a spare valve socket. According to Phil Skins at Nova Distribution, this allows the owner to swap one of the valves for one that requires a different connection. Warm Audio says it has sourced modern valves that are as close as possible to the spec and sound of the original’s, but purists have the opportunity to replace one for an older model that might be more to their taste. I am pleased to see that they’ve thought about this.

The other highly important component is the opto-cell – sometimes more commonly known as the photocell or optocoupler. This is believed to be key to the character of an LA-2A, directly affecting parameters such as the attack and release times. When Universal Audio reissued the LA-2A, there was a lot of fuss made about the opto-cell and they even researched manufacturing it with the old production methods. To the best of my knowledge, they still produce them in this old-school fashion. Inside the Warm unit there is an ‘off-the-shelf’ component, the Kenetek opto-cell, which is considered one of the best available today. In my eyes, even if it doesn’t match the true LA-2A sound, this would still be a very worthy addition to any studio.

In Use

Living with the WA-2A for a few weeks meant that I was able to use it in several scenarios. One of these was during a vocal session where I used the U87 and 1073 that I commonly employ in that studio. The signal was then passed through the WA-2A and out to the ADC. There is a valve mic available in that studio that I have started to use more readily, but I purposely didn’t when using this tube compressor as it might have over-colored or misguided any opinions. In hindsight, both the WA-2A and the valve mic aren’t overly colored, and it could have worked well.

Engineering with the WA-2A is an absolute joy. Dialling in the appropriate settings on these things is straightforward and more a case of whether or not the compressor is doing what you need. Alternatively, just running audio through tools such as this can add some character without any gain reduction occurring and the WA-2A certainly added something to the very clean sound of the U87.

On this particular session I had several vocalists taking it in turns on the mic and the WA-2A was perfect for the job. Instead of worrying about the levels coming off the preamp, I left the 1073 on the safe side and adjusted the peak reduction and output gain of the WA-2A. Here I found the best sound for each take and easily ensured a strong level to tape. While this isn’t strictly the preferred method of recording, in this fast-paced and dynamic session it was a quick and professional method of approaching the tracking. With the LA-2A-style compression it was often easy to adjust the parameters, sometimes mid-take, as the WA-2A was quite forgiving when delivering more than the desired level of gain reduction.

If I had to find something about the operation of the WA-2A that I wasn’t keen on, it would come down to small details. Firstly, the stepped controls for the output gain and peak reduction are obviously great for recalling settings on a mix, but they are quite large steps. Perhaps I’ve just got used to the fluid movements of the classic gear.

Secondly, with the pre-emphasis control located on the rear it would be virtually useless if the WA-2A were mounted in a sealed rack. I suppose they expect you to set and leave this control and it would look out of place if it were on the front panel. However, I found it very useful to have access permitting a change in color of the compression.

On to the next one

For the most significant test I had the pleasure of taking the WA-2A over to my professional contact and friend Jeff Calvert. I met him at his private facility, Silverdown Studios, with its well-maintained Neve console, Radar and Studer tape machines, a recently renovated EMT plate and U67 to mention just a few of the many highlights. He is also the proud owner of a Universal Audio LA-2A reissue. Although not a model from the ‘60s, these units are renowned for being as close as you can get, which are built by the same methods, so I was keen to hear the differences.

Above: Jeff Calvert adjusting the LA-2A reissue at his Silverdown Studios

We lined up the two units on a previous upright bass recording Jeff had and to be really honest, we found it hard to spot any difference. There are a couple of observations, however. Firstly, it was a wonderful recording, played by a world-class musician with a beautiful instrument. I also felt as if the compression on the WA-2A was slightly more active until I backed off the pre-emphasis control. Doing so led to a setting where the two units sounded almost identical.

We also tried the two compressors in turn on a lead vocal. Again this was an excellent recording with Jeff’s U67 and had initially been captured on tape before being recorded onto the Radar system. The similarities between the two units were immediately obvious, which I find astonishing. However, I found the reissue model to offer a few subtle differences, which all add up to a greater good. For example there was more ‘air’ in the sound with the UA unit and on the bolder long notes of the performance, the color from the different valves was clear. The Warm Audio unit had less character in general, and the character it presented was of a different color. There was a more apparent ‘raspiness’ of the saturation that the UA unit delivered. Obviously all the so-called ‘original’ units, including the reissues in this case each have an individual sound due to the nature of tubes and the optocoupler/photocell. In my experiment, there was a difference, but perhaps it would be less obvious with another unit.


The WA-2A is a well-built unit utilising the best of parts commercially available today. It offers a sound that’s easy to work with and a recognisable 2A compression style. Warm Audio has achieved its goal of developing an affordable clone of one of the most famous compressors of all time. Future owners of these units won’t be disappointed and I believe they will find a use for one in any studio setup.

The burning question, I guess, is how close the WA-2A is to the LA-2A. I believe it’s a case of what you pay for is what you get. Compared to the original hardware units, the WA-2A certainly sits alongside them, but I wouldn’t go as far to say that it’s a replacement. This is of course reflected in the considerable difference in price, which for some will be a very quick deciding factor.

Key Features

  • Premium grade CineMag USA transformers
  • Kenetek opto-attenuator
  • 2U rack-mountable unit
  • Fully discrete signal path
  • Socketed to allow for retro-fitting other opto-cells


Simon Allen is a freelance internationally recognised engineer/producer and pro audio professional with over a decade of experience. Working mostly in music, his reputation as a mix engineer continues to reach new heights.