For those players who love the huge, bold sound of the 1×15” 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 Class A / Class AB power amp wiring for 35, 45 or 60 watts of vintage American tone.

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.

  • Switchable Class-A (35 Watts) or Class-AB (45 / 60 Watts)
  • Independent BASS and TREBLE controls
  • All-tube reverb
  • Output-tube tremolo
  • Tube or Silicon Rectifier
  • 4x 12AX7
  • 1x 12AT7
  • 2x 5881 / 6L6 power tubes
  • 1x 5U4 Tube Rectifier
  • 1 x 15″ Supro TB15 speaker
  • Cab Size: 23 5/8” x 19” x 10 1/2” – 60 x 48 x 27 cm
  • Blue Rhino Hide tolex
  • 52 lbs – 24 kg
  • Assembled in USA
  • Engineered by Bruce Zinky, Thomas Elliott and David Koltai
  • MPN : 1675RT-U  
  • UPC : 00181118090265

Audio MIDI Plus is committed to deliver the best experience for our customers. If for some reason you are not satisfied with your purchase, you may return it for a refund of the purchase price, an exchange or a store credit within 30 days from the ship date. 

In the unlikely event that you received a defective product, a wrong product, or damaged product, Audio MIDI Plus will replace it at no charge of any additional shipping cost. We will send you a prepaid label to return the item, and ship you a replacement. You will not incur any shipping charges. Please notify us of any of damaged, defective or misshipped products within 14 days.

After 30 days, you may request manufacturer warranty if your item malfunctions. Unless otherwise specified, Audio MIDI Plus is an authorized dealer for all the brands we represent.

How to request a return:
Please email us or call us to obtain a RMA number. All returns must be in a re-sellable condition and include all packing materials, accessories and paperwork. We may apply a restocking fee if the returned products fall into these following categories:

  • Missing original packaging, manuals, accessories, or any contents that was included
  • RMA number was not associated with the return
  • Items not in original like new condition

Please send all returns to:
Audio MIDI Plus Returns
3725 Saddle Drive,
Carlsbad, CA 92010

The following items are not returnable, unless received DOA, in which we will send a replacement:

  • Software
  • Electronic Delivery of Software
  • Special orders
  • DVD’s

Items that fall into the in mouth and in ear use category, such as mouthpieces, earphones, ear plugs, harmonicas, cannot be returned due to health regulations

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