Fender Blues Junior IV Review: The Best Small Tube Amp You Can Buy?
The Fender Blues Junior has been one of the best-selling tube amps in the world since it came out in 1995. It's not hard to see why: 15 watts through a 12-inch speaker, all-tube signal path, reverb and master volume built in, at a price that's stayed reasonable despite decades of inflation. The IV version, released in 2018, made real improvements to the voicing and component quality. But is it still the best small tube amp at its price?
We spent three weeks with the Blues Junior IV at home, in a rehearsal space, at a small club gig, and in a recording session. We used a Strat, a Les Paul, a Telecaster, and a hollow-body archtop. Here's the full picture.
Specs and What Changed in the IV
The Blues Junior IV runs three 12AX7 preamp tubes and two EL84 power tubes, the same setup as a Vox AC15, which gives it a slightly different character than EL34 or 6L6 powered amps. The IV update revised the voicing by changing the tone stack values, giving it a slightly brighter, more present clean tone than the III. The speaker is a Celestion A-Type, a real upgrade over the generic speaker in earlier versions.
Controls: Volume, Middle, Bass, Treble, Master Volume, Reverb, and a Fat switch that kicks in a mid-boost for a thicker, warmer sound. The Master Volume matters a lot here. It lets you dial in power-tube breakup at lower listening volumes, which the original Blues Junior never had.
The Clean Tone
The Blues Junior IV's clean tone is excellent: warm, slightly glassy, and responsive to how you pick. At low volumes with the volume control under 4 it stays clean and clear. Single-coils sound especially good here. A Telecaster through this amp at moderate volume is one of the most satisfying tones in all of guitar. The reverb is simple spring-style that sounds natural and musical at moderate settings.
The Fat switch deserves mention here: engaged on the clean channel, it adds a mid-warmth that transforms the tone from "chimey Fender" to something closer to a Vox-style richness. It's a meaningful tonal shift, not a subtle one. Most players will end up deciding which setting becomes their baseline and staying there.
One honest limitation: clean headroom is modest at 15 watts. At higher volumes it starts breaking up, which is great for blues and classic rock but limiting if you need crystal-clean tone at stage volume. If clean headroom matters most to you, get a higher-wattage amp instead.
Drive and Breakup Character
The Blues Junior IV's natural breakup, when you push the volume between 6 and 9, is one of the best things about it. The EL84 power tubes give you a compressed, harmonically rich breakup that sounds distinctly different from 6L6 or EL34 amps. It's tighter and faster, more "chimey crunch" than "raunchy blues." For blues and classic rock it's superb. For heavier styles it runs out of gain before you get anywhere near useful.
As a Pedal Platform
The Blues Junior IV is one of the best pedal platforms at its price, with one caveat: it responds best to pedals at low-to-medium gain. High-gain distortion pedals can sound harsh through it because the amp's natural EQ is already on the bright side. The sweet spot is light overdrive and boost pedals pushed into the amp's natural breakup. That combination produces genuinely great results.
Specifically great: TS-style overdrives (TS9, SD-1), clean boosts (EP Booster, Xotic RC Booster), and transparent drives (JHS Morning Glory). Reverb and delay pedals also shine through this amp, since the clean tone is a flattering platform for time-based effects.
Gigging With the Blues Junior
For small-to-medium venues, the Blues Junior IV is a genuinely great gigging amp. At 15 watts through a 12-inch Celestion, it gives you enough volume for most club settings without needing to drive it so hard the tone suffers. The single-channel design with master volume means you're working with one tone per set, which can be limiting, but most players who buy a Blues Junior already know this and lean on pedals for variety.
The amp weighs 31 lbs, which is reasonable for a tube combo. The carry handle position isn't ideal, but it's manageable solo. For larger venues or outdoor stages, 15 watts starts showing its limits even with mics on it, though a good FOH engineer can work around that.
Pros
- Exceptional clean and light-breakup tone
- Excellent pedal platform at moderate gain
- Celestion A-Type speaker is a genuine upgrade
- Built-in reverb is musical and natural
- Good value at ~$650
- Portable at 31 lbs
Cons
- Limited clean headroom at stage volume
- Single channel limits live tonal flexibility
- Breaks up early with high-output humbuckers
- Can sound harsh with high-gain pedals
- No effects loop
Fender Blues Junior IV Score: 8.8 / 10
The Fender Blues Junior IV remains one of the best small tube amps you can buy for the money. The clean tone, the breakup character, and how it responds to light overdrive pedals are all genuinely excellent. Its limits (modest headroom, single channel, no effects loop) are real but well known going in. If you play blues, country, indie, or classic rock in small-to-medium venues and want a reliable, great-sounding tube amp that fits in the back seat of a car, the Blues Junior IV is the obvious answer.