1675RT Rhythm Master

For those players who love the huge, bold sound of the 1 x 15” Thunderbolt amp, but need a lush, all-tube reverb to fill out their sound, Supro presents the 1675RT Rhythm Master amplifier. Rooted in Supro tradition, this vintage-inspired model is loaded with independent bass and treble controls, six-spring long-pan reverb, output-tube tremolo and switchable power. The Rhythm Master’s 35-Watt Class A (Cathode Bias) mode delivers a more spongy, vintage character while the 60-Watt Class AB (Grid Bias) mode delivers faster transient response with maximum available headroom and volume.

The Rhythm Master’s USA made custom 15” driver is the most accurate and true sounding 15” guitar speaker on the market, with a full, broadband sound that is never muddy. To create this signature speaker, we worked with Eminence to combine the best elements of our favorite vintage 15” speakers (Jensen C15PS & JBL D130) with modern construction methods and materials to achieve a vintage voiced driver with superior power handling and juicy bottom end.

The unique power amp topology of the Rhythm Master not only allows for players to change the texture and output volume of the amp but it also provides two very different, all-tube tremolo effects depending on whether Class A (cathode bias) or Class AB (grid bias) mode is selected. The cathode bias tremolo is vintage Valco/Supro all the way, where the overall depth of the effect changes along with the dynamics of your playing. The grid bias tremolo is gives a much deeper, stronger and more pronounced throbbing effect. Since the tremolo is performed by modulating the bias of the output tubes, the reverb necessarily comes before the tremolo effect, for a mesmerizing combination of pure tube reverb and tremolo when both effects are combined.

Circuit Type: All-tube Supro Circuit
Wattage: Switchable Class-A (35 Watts) or Class-AB (45/60 Watts)
Channels: Single Channel with Bass and Treble Controls
Tremolo: Yes, foot-switchable – purchase here!
Reverb: Yes, foot-switchable – purchase here!
Assembled in New York, USA
Preamp Tubes: 4x 12AX7, 1x 12AT7
Power Tubes: 2x 5881/6L6, 1x 5U4 Tube Rectifier
Speakers: 1 x 15″ Supro TB15
Cabinet Dimensions (in.) 23 5/8” x 19” x 10 1/2”
Cabinet Dimensions (cm.) 60 x 41 x 27 cm
Weight (lbs) 52 lbs
Weight (kg) 24 kg
Tolex Blue Rhino Hide tolex
1675RT Rhythm Master
Blue Rhino Hide Tolex
Supro TB15 Speaker