69 Blue Line Bass
Headrush Amplifiers

69 Blue Line Bass

Inspired by Ampeg SVT 300w

The model 69 Blue Line Bass is an amplifier designed for electric bass, inspired by classic vintage amps with large headroom, designed to offer:

  • Clean, powerful and defined sound
  • Deep but controlled lows
  • Perfect for funk, rock, jazz and fusion

Includes advanced EQ controls such as Mid Frequency and Ultra Hi/Low, for precise sound shaping.

RockJazzFunkPopCountryBassFusion

Controls

Bright

Activate or deactivate the high frequency boost:

  • Y → brighter and more defined sound
  • N → warmer and rounder sound
  • Useful for slap and definition on the high strings
Treble

Control the high frequencies:

  • Low → smooth sound
  • High → bright and punchy
  • Adjust presence and attack
Mid

Controls the mid frequencies:

  • Low → scooped sound
  • High → more presence and definition
  • Fundamental for standing out in the mix
MidFreq

Select the frequency on which the

Mid control acts:

  • Low (200–400 Hz) → body and warmth
  • Medium (400–800 Hz) → presence and punch High (800–1.5 k
  • Hz) → definition and attack Allows a very precise and musical EQ
Bass

Control the low frequencies:

  • Low → tighter sound
  • High → full and deep
  • Be careful not to overdo it to avoid a “dough” sound
Ultra Hi

High frequency boost:

  • Low → light effect
  • High → very bright and defined sound Ideal for slap and percussive technique
Ultra Low

Low frequency boost:

  • Low → control
  • High → deep, powerful bass Adds weight to the sound
Volume

Controls the overall level of the preamp:

  • Low → clean
  • High → more presence and drive
  • Does not introduce significant distortion
Output Level

Controls the final volume:

  • Negative → attenuation 0 d
  • B → neutral level
  • Positive → final boost Does not alter the timbre, only the volume

Pro Tips

BEHAVIOR OF THE AMPLIFIER

  • Clean, powerful sound with great headroom
  • Very flexible EQ thanks to MidFreq and Ultra Hi/Low
  • Excellent definition even with high low frequencies
  • Volume + Output Level → balance the overall level

Advice:

  • Mid + MidFreq → essential to stand out in the mix
  • Ultra Hi → for slap and attack
  • Ultra Low → for depth and weight
  • Bright → adds immediate definition

Final advice:

  • Mid + MidFreq → key for definition and presence
  • Ultra Hi → perfect for slap and modern technique
  • Ultra Low → adds depth without losing control
  • Bright → immediate attack on high frequencies

Setup Examples

Clean / balanced sound

BrightN
Treble50%
Mid50%
MidFreq500Hz
Bass50%
Ultra Hi30%
Ultra Low30%
Volume50%
Output Level0dB

Funk / slap

BrightY
Treble60%
Mid45%
MidFreq800Hz
Bass55%
Ultra Hi65%
Ultra Low40%
Volume55%
Output Level+1 dB

Powerful rock/bass

BrightN
Treble55%
Mid60%
MidFreq400Hz
Bass65%
Ultra Hi40%
Ultra Low65%
Volume60%
Output Level+2 dB

Flea – “Funk Punch”

BrightY
Treble60%
Mid50%
MidFreq700Hz
Bass55%
Ultra Hi60%
Ultra Low45%
Volume55%
Output Level+1 dB

Description: Funky sound with strong attack and midrange punch. Perfect for energetic Red Hot Chili Peppers style slaps and grooves.

Marcus Miller – “Slap Hi-Fi”

BrightY
Treble65%
Mid40%
MidFreq900Hz
Bass60%
Ultra Hi75%
Ultra Low50%
Volume55%
Output Level+1 dB

Description: Modern slap sound, very bright and defined, with deep lows and crystal clear highs. Ideal for slap and fusion techniques.

Geddy Lee – “Prog Rock Growl”

BrightN
Treble55%
Mid65%
MidFreq400Hz
Bass60%
Ultra Hi40%
Ultra Low55%
Volume60%
Output Level+2 dB

Description: Aggressive and mid-range sound, perfect for melodic lines and progressive rock. Maintains definition even in dense mix.

Quick tip:

  • Flea → more punch and groove
  • Marcus Miller → modern and hi-fi slap
  • Geddy Lee → highlighted averages and presence in the mix