Unlike some designs, which simply have a valve in the circuit, a Vari-Mu compressor uses the valve for gain control. As pointed out by Case (2007) a circuit is sent to a valve by the level detection unit to alter its gain, which results in compression of the audio signal. Vari-Mu compressors do not have a ratio control and increasing amounts of gain reduction are achieved with louder levels (Izhaki 2008). Due to the use of a valve for gain reduction, Vari-Mu compressors are not as fast as the transistor-based units.
This can make them a suitable choice for drum busses and full mixes when preservation of transients is desirable. The classic Fairchild 660/670, Altec 436 and modern Manley Variable Mu are all examples of compressors that use valves for gain reduction. Optical compressors (more commonly known as Opto) use a light and a light sensitive resistor to alter gain (Case 2007). A bulb, illuminated by the level detection circuit, shines on a photo-resistant material to control the amount of gain change. As noted by Izhaki (2008) despite the fact that light is used, Opto compressors are slow to respond to rapidly changing musical dynamics making them a poor choice if quick clamping on transients is required. The classic UA LA-2A and modern Tube Tech CL-1B are examples of popular Opto compressors. VCA Compressors are arguably the most common design. These compressors use a transistor based voltage-controlled amplifier. When using a VCA in a compressors circuit the control voltage is derived from the input signal and any gain reduction is related to this level. In simple terms, more level, more voltage more gain reduction.
This is a seriously good compressor at a very reasonable price.” Pre-used models in excellent condition should cost around £300 – £400.VCA compressors are considered to be the most transparent of the hardware-based designs. Launched in 2013 but now discontinued, Lindell Audio produced the 17XS MkII which we described as “a thoroughly modern take on the classic UREI 1176 compressor with several useful features that make it an extremely versatile single-channel dynamics controller. Current cost is £609 for a single unit or £1,499 for a stereo-linked pair (Nova Distribution 02). The use of an external wall-wart power supply might put off some however, this means that Warm Audio has spent money on the components that really matter. Designed to offer the character of the much-loved Revision D, the WA76 delivers all of the 1176’s legendary performance and sound at a fraction of the price of the hand-wired UA 1176. It features a fully discrete signal path and uses superb CineMag transformers. This attention to detail does come at a price, though, with a genuine UA 1176LN costing around £1,999 ( For a more affordable, yet still great-sounding take on the original, check out Warm Audio’s WA76.
0 kommentar(er)
