Fender · Amp

Fender Blues Junior IV Settings Guide

The entry-point tube combo from Fender. 15W of American clean headroom with beautiful spring reverb.

The best Fender Blues Junior IV settings start with: Volume at 5/10, Bass at 5/10, Mid at 6/10, Treble at 6/10, Master at 5/10, Reverb at 3/10. Adjust from there based on your amp, guitar, and room volume. For Blues: Volume 6/10, Bass 5/10, Mid 7/10, Treble 5/10, Master 4/10, Reverb 3/10.

What Each Control Does

Volume
Silent
Loud
Increases preamp gain and output. The amp starts to break up naturally around 6-7.
Bass
Thin
Warm
Low-end body. Cut at high volume to prevent boom in small rooms.
Mid
Scooped
Nasal
Midrange presence. Higher values = more cut-through.
Treble
Dark
Bright
Sparkle and edge. Fender clean sparkle lives between 6 and 8.
Master
Silent
Full
Output volume without affecting preamp gain. Use Master high and Volume low for bedroom.
Reverb
Dry
Wet
Spring reverb. 3-5 is musical; above 7 becomes washy.
FAT Switch
Off
On
Engages a mid-boost circuit — adds warmth at the cost of clean headroom.

Recommended Starting Settings

Safe starting positions for any style. Adjust from here based on your amp and room.

5
Volume
5
Bass
6
Mid
6
Treble
5
Master
3
Reverb

All values on a 0–10 scale. These are starting points — fine-tune by ear.

Settings by Genre

Blues
Volume6
Bass5
Mid7
Treble5
Master4
Reverb3

Push the Volume so the amp breathes. FAT switch on for rhythm work.

Country
Volume4
Bass4
Mid5
Treble7
Master5
Reverb4

Bright and clean. High treble, lower mids. Compression pedal in front.

Jazz
Volume4
Bass6
Mid6
Treble4
Master5
Reverb2

Darker, warmer sound. Pull treble back. Minimal reverb.

Artist Settings

Documented settings used by professional guitarists on this unit.

Volume7
Bass5
Mid6
Treble6
Master4
Reverb3

Mayer runs Blues Juniors loud with volume pushed into natural breakup. Treble slightly cut.

Tips & Common Mistakes

  • The tonal sweet spot is with Volume at 6-7 — the amp starts to breathe and the tubes compress naturally.
  • Use the Master volume to control stage volume while keeping Volume (preamp) high.
  • The FAT switch adds warmth but reduces headroom — keep it off for spanky clean Strat tones.
  • The Blues Junior doesn't have a bright cap on the volume control — it's voiced brighter at lower volumes. This is by design.

Fender Blues Junior IV — Common Questions

Best starting settings for Fender Blues Junior IV: Volume at 5/10, Bass at 5/10, Mid at 6/10, Treble at 6/10, Master at 5/10, Reverb at 3/10. Adjust from there based on your guitar, room, and playing style.

For Blues: Volume 6/10, Bass 5/10, Mid 7/10, Treble 5/10, Master 4/10, Reverb 3/10. Push the Volume so the amp breathes. FAT switch on for rhythm work.

For Country: Volume 4/10, Bass 4/10, Mid 5/10, Treble 7/10, Master 5/10, Reverb 4/10. Bright and clean. High treble, lower mids. Compression pedal in front.

Volume: Increases preamp gain and output. The amp starts to break up naturally around 6-7. (Silent to Loud). Bass: Low-end body. Cut at high volume to prevent boom in small rooms. (Thin to Warm). Mid: Midrange presence. Higher values = more cut-through. (Scooped to Nasal). Treble: Sparkle and edge. Fender clean sparkle lives between 6 and 8. (Dark to Bright). Master: Output volume without affecting preamp gain. Use Master high and Volume low for bedroom. (Silent to Full). Reverb: Spring reverb. 3-5 is musical; above 7 becomes washy. (Dry to Wet). FAT Switch: Engages a mid-boost circuit — adds warmth at the cost of clean headroom. (Off to On)

The tonal sweet spot is with Volume at 6-7 — the amp starts to breathe and the tubes compress naturally. Use the Master volume to control stage volume while keeping Volume (preamp) high. The FAT switch adds warmth but reduces headroom — keep it off for spanky clean Strat tones. The Blues Junior doesn't have a bright cap on the volume control — it's voiced brighter at lower volumes. This is by design.

John Mayer settings: Volume 7/10, Bass 5/10, Mid 6/10, Treble 6/10, Master 4/10, Reverb 3/10. Mayer runs Blues Juniors loud with volume pushed into natural breakup. Treble slightly cut.