Helix is a small German company that produces high-quality, meticulously engineered products. One example is the B4 Precision, a Class A four-channel amplifier. At 4 ohms, the output is rated as 60 watts to four channels or bridged at 180 watts to two channels.

With onboard variable crossovers ranging from 30Hz to 3,000Hz and a choice of high-pass, low-pass, or full-range, this amplifier can be used for four main speakers, two subwoofers, or two full-range channels with a bridged mono subwoofer. Overall frequency response is rated from 20Hz to 20,000Hz, so the B4 Precision will produce a good, strong signal regardless of the configuration.

One notable feature is the adjustable-speed cooling fan, which is located on the top of the unit. This fan not only has a selectable speed, but it has an adjustable activation temperature. There are separate speaker protection circuits on each channel that detect a ground fault, speaker short-circuit, or low impedance. Although not a very powerful unit, the Helix B4 Precision is a very clean-sounding and (no pun intended) precise amplifier.