Vintage Tube Compressor/Limiter Model 670

IK Multimedia's Model 670 is a meticulous digital emulation of the Fairchild 670, the variable-mu tube limiter that defined transparent compression for mixing and mastering engineers. The plugin reproduces the hardware's dual-channel architecture faithfully, allowing independent processing of left and right channels or, via built-in M/S matrix decoding, mid and side components of a stereo mix - a capability particularly valued in mastering workflows where selective control of the stereo image is essential.

The sonic signature reflects the original's tube circuitry and gain reduction topology. Rather than operating as a traditional threshold-based compressor, the variable-mu design produces gentle, musical compression curves that become more aggressive as signals exceed the knee point. This character lends itself well to program material; drums naturally cohere into a unified instrument, while vocals acquire presence and harmonic richness without obvious compression artifacts.

The attack time proves extremely fast, making the Model 670 effective as a peak limiter, while its variable release times allow engineers to dial in everything from transparent dynamic control to more pronounced limiting action without the pumping characteristic of less sophisticated designs. The tube emulation contributes warmth across the frequency spectrum.

Best suited for mastering applications and stereo bus processing, the Model 670 also excels on drum submixes and vocal tracks where its gentle compression characteristics enhance musicality. For studios seeking the Fairchild sound without the considerable expense and maintenance demands of vintage hardware, this emulation delivers legitimate utility alongside its reputation value.