The Summit Audio TLA-50 is a tube leveling amplifier with a small footprint, a simple layout, and a very big sound. This is perhaps the best bang-for-the-buck piece of equipment in my entire studio. I find myself using it during tracking on nearly everything, including vocals, acoustic and electric guitars, bass, and just about anything else that could use a little warmth and gentle control before hitting my AD converters. The compression is extremely smooth, even at fairly high levels of gain reduction, and the tube stage really helps to warm things up and add a nice sense of weight and size to anything you put through it. I have tons of very good classic compressor emulations from Waves and other developers, but I still find myself routinely running things back through the TLA-50 during the mixdown stage if I feel they need to be a bit warmer and/or bigger. I think this is important to point out, because with most compressors under $1K, I might use them for control while tracking, but I seriously doubt I would ever choose them over a software compressor during mixing...the TLA-50, however, is in an entirely different league.
I can't comment on how this unit compares to its big brother, the TLA-100, but I have heard several people say that the TLA-100 is one of their favorite compressors for rap vocals, and I can vouch that the TLA-50 excels in this area as well. With the attack set to medium and the release set to fast, the compressor helps keep rap vocals very focused and in your face, which is usually exactly where you want a rap vocal to be. On sung vocals, a medium release proves perfect for gently controlling any exceptionally dynamic passages without destroying the natural feel of the performance, while a faster release adds urgency and excitement without any noticeable artifacts. On acoustic guitars, the TLA-50 really helps to glue a performance together and adds a wonderful sonic polish to the sound, while controlling the boominess you find on some instruments (such as a Martin HD-28). Also, unlike many other compressors, the TLA-50 is very low frequency friendly...bass guitars and kick drums sound huge through it, although you will likely need to use at least a medium release on certain bass guitar parts to avoid distortion. The TLA-50 also works well on drums and other percussive sounds, and can add a lot of energy and attitude to room mics when pushed hard. Surprisingly, it compares very favorably to something like the Waves CLA-76 in this application, with perhaps just a touch more distortion, which is sometimes exactly what you want.
Don't be fooled by the seemingly utilitarian layout of this unit...it is extremely flexible, and can handle just about anything you might throw at it. It is also built like a tank...I don't see it falling apart anytime in the next 20 years or so. If there is a downside, it's that the unit doesn't have quite as much headroom as I might like, but if you record to digital and are already being cautious about recording too hot, this should pose no problem. The unit can also be a bit noisy if you are pushing the gain past the middle point on the dial, but in most applications, I rarely find myself turning the Gain knob past 3, so the noise level never really becomes an issue except in cases where I am applying extreme amounts of compression. I deducted a couple of points from the Features rating due to the lack of a ratio control or infinitely variable attack and release controls, but honestly, you don't need them...this thing will almost always sounds great no matter where you set the controls.