Supro S6420P Thunderbolt Plus

by Supro
SKU S6420P

The Supro Thunderbolt Plus amplifier adds switchable power amp topology to the legendary 1964 Supro Thunderbolt.

This gives you the original 35-Watt “Class A” Cathode bias sound as well as beefy 45-Watt and 60-Watt Grid bias modes for additional headroom and tonal variation. This unique design is implemented via a three-way selector switch on the front panel.

Normal and Extra-hot input options, combined with a wide range of available gain on tap, allow you to fine-tune the texture and response of this amp’s massive sound. Turned all the way up, the Thunderbolt exhibits nearly zero self-noise, yet it puts out enough volume to be easily heard on large venue and theatre stages, with overdrive completely controlled by the guitar’s volume knob. The 35-Watt and 45-Watt modes both deliver the sag and bluster of the 5U4 tube rectifier while the 60-Watt mode uses a silicon rectifier to unleash maximum Thunderbolt power. The 60-Watt mode’s faster transient response and ample headroom is wonderful for pedals, and brings the Supro sound loud and clear to any size venue.

Massive custom transformers and lightweight, vintage-correct cabinetry—combined with the best sounding 15” guitar speaker money can buy—put the Thunderbolt in a class of its own. With the amp turned all the way up, chords ring with exceptional clarity and definition amidst copious amounts of tube overdrive and output-stage saturation. The variable power switching found in the Thunderbolt Plus model is an over-the-top hot-rod custom luxury guitar experience, decadently brought to you by Bruce Zinky and Dave Koltai.



All-tube Supro circuit
Normal and Hot inputs
Unique Switchable Wattage
35-Watts “Class A” w/ Tube Rectifier
45-Watts “Class AB” w/ Tube Rectifier
60-Watts “Class AB” w/ Silicon Rectifier
1×15 Supro TB15 speaker
5U4 Tube Rectifier
Blue Rhino Hide
Assembled in USA
Vintage design by Valco
Re-engineered and Modified by Bruce Zinky & David Koltai


Tube Complement

2x 12AX7EH
2x 5881 / 6L6WGC
1x 5U4GB


Cabinet Dimensions

23 5/8” x 19” x 10 1/2”
45 lbs