This gives the CLA-3A more flexibility in terms of how much compression is applied to the signal. variable ratio: The CLA-2A has a fixed compression ratio of 4:1 (but the ratio will fluctuate depending on the source), while the CLA-3A has a variable ratio that can be adjusted from 2:1 to 10:1. This gives the CLA-3A a faster attack time and a more aggressive sound, while the CLA-2A has a slower attack time and a more gentle sound. electro-luminescent gain reduction: The CLA-2A uses an opto-gain reduction element, while the CLA-3A uses an electro-luminescent (EL) gain reduction element.