Universal Audio UAFX Flow Tremolo

The Universal Audio UAFX Flow is a 3-mode tremolo is an evolution of the Californian company’s Astra Modulation Machine pedal. Unlike the latter, it only does tremolo sounds.

The three tremolo voices are emulations of classic vintage units: the Dharma mode draws inspriration from the harmonic tremolos found in Uni-Vibes and Magnatone amps; the 65 mode recreates the classic tremolos found in vintage Fender amps, while Square is a more modern, choppy sounding option.

Two switches on the back panel allow to access Buffered or True bypass and to transform the footswitch into a Tap Tempo controller.

back panel

Here’s the launch video of the Flow.

Universal Audio UAFX Flow Vintage Tremolo, Builder’s Notes

  • Evolved from our flagship Astra Modulation Machine, Flow Vintage Tremolo gives you three flavors of tube-driven wiggle and shake — from old school to modern — in a dapper, compact package.
  • Get three stunning emulations of legendary tube amp tremolo effects, from opto to harmonic
  • Explore rich, authentic tones and effects with perfectly emulated tube preamp section
  • Sync your trem with tap tempo and add boost effects with Volume control
  • Rely on timeless UA craftsmanship, built for years of rock-solid performance


  • Authentic emulations of three tube-driven tremolo effects, captured in a compact stompbox
  • Perfectly captured tube preamp for fat, three-dimensional tremolo tones
  • Three tremolo modes: Dharma (harmonic tremolo), 65 (round, sine wave), and Square (choppier, square wave)
  • Onboard tap tempo for syncing trem effects
  • Volume control and true/buffered bypass
  • Timeless UA design and craftsmanship, built for decades of dependable performance