Fender Blues Junior IV: A Beloved Classic Revisited

The Fender Blues Junior has been a staple on stages and in studios for decades. The fourth-generation model — the Blues Junior IV — refines the formula with upgraded components and a tweaked voicing, but does it still earn its reputation? We spent several weeks playing this amp across a range of styles to find out.

Key Specifications

  • Power: 15 watts (all-tube)
  • Speaker: 12" Celestion A-Type
  • Tubes: 3x 12AX7 preamp, 2x EL84 power amp
  • Controls: Volume, Master, Treble, Mid, Bass, Reverb, Fat switch
  • Weight: Approximately 15 kg
  • Channels: Single channel with Fat switch voicing option

Clean Tone

The Blues Junior IV's clean channel is warm, glassy, and thoroughly Fender. Plug in a single-coil guitar and you're immediately rewarded with that chimey sparkle the brand is famous for. The upgraded Celestion A-Type speaker contributes significantly here — it's more articulate and less boxy than the older Jensen C12N that shipped with earlier versions.

Headroom is modest at 15 watts, which means the amp begins to break up at moderate volumes. For home players, this is a genuine asset. For gigging players needing pristine cleans at stage volumes, you may find yourself pushing into breakup sooner than expected.

Overdrive and the Fat Switch

Engaging the Fat switch adds a noticeable midrange thickening — it's not subtle. This voicing pushes the amp into natural overdrive territory more readily and works particularly well with humbucker-equipped guitars. The onboard overdrive sounds organic and touch-sensitive, responding beautifully to how hard you pick.

One limitation: there's no dedicated drive control. You're managing overdrive through your playing dynamics and guitar's volume knob, which purists will love but players who want a simple "crunch" setting may find fiddly.

Reverb

The spring reverb on this amp is genuinely excellent for the price bracket. It's lush without being washy, and the range of the reverb knob gives you everything from a subtle room ambience to a full surf-drip effect.

Verdict

The Fender Blues Junior IV remains one of the most practical and tonally satisfying small tube amps on the market. It's not without compromises — limited clean headroom and the absence of multiple channels will rule it out for some players — but for blues, classic rock, country, and jazz, it's hard to beat at this size and price point.

Pros

  • Exceptional Fender clean tone with upgraded speaker
  • Beautiful, musical spring reverb
  • Lightweight and practical for gigging
  • Touch-sensitive, organic overdrive

Cons

  • Limited clean headroom at 15 watts
  • No separate drive/gain control
  • Single-channel design may not suit all players

Bottom line: If you're after a compact, no-nonsense tube amp with classic Fender character, the Blues Junior IV is still a benchmark for its class.