Caelum Audio released Tape Cassette for desktops, and as their first iOS app. This tape saturation effect is free on all platforms, and supports AUv3 and IAA on iOS. The desktop version can be downloaded here.
Tape Cassette App Store Description:Tape Cassette is an easy to use audio plugin that gives your music warmth, noise and character. Whether it’s an effect on the master for an overall lofi / indie texture, or as an insert to warm up individual channels, Tape Cassette gives you the tools to turn your music into a cosy, nostalgic listening experience. Take the plugin into experimental territory by using the wow & flutter parameters and spin your sounds into a frenzy, or use the saturation parameter to heat up the sounds into a distorted cacophony.
⁃ Saturation (+/-24dB)
⁃ Low Pass Filter (8-22KHz)
⁃ Noise -80 to 0 dB
⁃ Wow 0 - 100%
⁃ Flutter 0 - 100%
Tape Cassette is both a stand-alone application as well as an AUv3 plugin, meaning it works within iOS hosts such as GarageBand.