The Koch Studiotone 20 Combo: 

Three Channels of Pure Expression Designed as a versatile, go-to amplifier for players of all styles, the Jupiter Junior features three foot-switchable channels:

  1. Cool (Clean): Delivers a bright, chimey clean with rounded warmth and exceptional headroom. Crank it up to experience a snappy, bluesy edge-of-breakup bite.
  2. Hot (Overdrive): Serves up a thick, singing overdrive with rich mids—perfect for classic rock riffs and warm, expressive lead playing.
  3. Hot Gain Boost: Adds extra saturation, compression, and grit, pushing the amp into heavy, high-gain hard rock territory.

Smart Tools for Stage, Studio, and HomeDespite its classic 1960s-inspired aesthetic, the Jupiter Junior is loaded with modern utility tools:

  1. Built-in Power Dimmer: Seamlessly scale your output power anywhere from 20 watts all the way down to 0 watts. Enjoy cranked-amp power-stage saturation at whisper-quiet bedroom volumes.
  2. Passive Speaker-Emulated Recording Out: Connect directly to a DAW interface or front-of-house mixing console with a highly convincing, mic'd-cabinet emulation filter.
  3. Speaker On/Off Switch: Easily turn off the internal speaker for silent recording or late-night headphone practice.
  4. Jensen Falcon C10-40 Speaker: Loaded with a premium 10" Jensen speaker in a resonant, partially closed-back cabinet to ensure punchy, tight, and remarkably focused low-end projection.
  5. Professional Routing: Features a custom-voiced spring-emulated reverb, an extension speaker output, and a fully buffered serial effects loop to keep your modulation and time-based pedals sounding pristine.

Boutique Hybrid Tone Without Compromise

If you are looking for authentic, touch-sensitive tube dynamics in a highly reliable, compact, and affordable package, the Koch Jupiter Junior 20 Combo is the ultimate solution.
Based on its iconic big brother, the Jupiter 45, this 20-watt vintage-style hybrid combo proves that you don't need a massive budget or a back-breaking rig to capture true boutique guitar tones.

At the heart of the Jupiter Junior is Koch’s proprietary ATR (Authentic Tube Response) technology. By placing one 12AX7 tube in the preamp and another 12AX7 in the power amp stage, we bridge the gap between tube warmth and solid-state reliability.
The high-end MOSFET power section behaves exactly like a full-tube amplifier, delivering natural compression, organic sag, and incredible touch-responsiveness at any volume.

TAke A CLOSER LOOK

ATR Athentic Tube Responce

At the heart of the Jupiter Junior is our proprietary ATR (Authentic Tube Response) technology. By placing a 12AX7tube in both the preamp and power stage, this hybrid design delivers the organic sag, natural compression, and touch-responsiveness of a full-tube amp at any volume—perfectly blending genuine tube warmth with solid-state reliability.

Jensen C10-40

A very successful and versatile 10”, the Falcon 10 adds a new dimension of openness to the classic, fat and warm tone The seamed cone membrane delivers an unexpected bass response for its 10” size and it is balanced perfectly with its sweet, yet cutting and present high end. 

Featherweight Build, Heavyweight Performance

Weighing in at a mere 12 kg, the Jupiter Junior 20 is a lifesaver for the gigging musician. But don't let its ultra-portable footprint fool you—this compact combo packs more than enough punch and stage volume to hold its own in a live band setting. It’s a common sight on club stages today, proving you don't need a back-breaking rig to deliver a massive, room-filling tube performance.

SPECIFICATIONS:

Amp configuration 

  1. 20W Hybrid ATR amplifier (ATR = Authentic Tube Response)
  2. 1x 12AX7 tube in the pre-amp
  3. 1x 12AX7 tube in the power amp
  4. High Voltage Mosefet power control

The TONE

  1. Three foot-switchable channels: Cool (clean), Hot (overdrive) and Hot Gain Boost
  2. Volume control for the Cool channel and separate Gain and Volume controls for the Hot channel
  3. Passive Bass-Mid-Treble tone controls for both channels

Connectivity and OUTPUT

  • Spring emulated reverb with Volume control
  • Dimmer (power Control) for continuous control of the output power between 0W and 20W
  • Buffered serial effects loop
  • Recording output with passive speaker emulation filter
  • Speaker on/off switch for silent recording
  • Extension speaker jack
  • 1x 10” Jensen Falcon C10-40 speaker

HARDWARE & HANDLING

​-Two button footswitch (not included) with:
* Channel select
*  Gain Boost 

COMBO DIMENSIONS & Weight

  • Dimensions 45(w) x 42 (h) x 23.5 (d) cm
  • Weight ca. 12 kg