I recently purchased the IGS 576 and I must say.. At first, I was a somewhat skeptical, Could this 1U-500 module actually produce an authentic representation of the revered 1176 Blue Stripe? Without having an original UREI Rev A 1176 to compare it to… I can't say for sure. However, I can tell you that this thing sounds amazing! This is an incredible value, for a unit of this quality! The 576 has all of the ratios that you’d expect from an 1176 (4:1, 8:1, 12:1, 20:1), and of course the “all-buttons-in mode”. This particular unit also has a 2:1 ratio, that is a lot more useful that I originally thought (especially when using seriel compression). For vocals I love to feed my 1176 output directly into an opto compressor. This tends to help smooth out the vocal with the 1176 first catching any peaks. Using the 576’s 2:1 & 4:1 ratios with fast attack/fast release directly into the IGS LA One 500… is pure magic! I do own other 1176 style compressors and I can say that this unit does have a little more attitude (what the Rev A is known for) than my other units. If you want a clean/transparent comp, look for another unit. Although I can honestly say that the 2:1 ratio will get you the most transparent sound that you'll probably ever get from any 1176 style compressor. This thing is extremely versatile and I would strongly recommend the IGS 576 to anyone looking for a high quality compressor! Especially if you are looking to buy something in the 1176 realm… you cannot go wrong with this little ol’ Blue Stripe!! My only regret is not getting a stereo matched pair!