Bass Booster Circuit


Bass Boost is today's sound... whether it's the driving, gut-vibration pulsation of disco, or the solid bass line of soft, hard, or laid-back rock. One way to get the modern bass-boost sound without running out and buying an all-new expensive piece of equipment is to use a Bass Booster between your guitar, electronic organ or what-have-you, and the instrument amplifier. A bass booster strips the highs from the instrument's output signal and amplifies low frequencies, feeding on "all-bass" sound to the instrument amplifier. Naturally, the bigger the speaker used with the amp, the more powerful the bass: use 15-inchers with the Bass Booster and you can rattle the windows. Bass Booster is powered by an ordinary 9 volt transistor radio battery. It can be assembled on a small printed board or on a veroboard using point to point wiring. The booster connects between your instrument and its amplifier through two standard RCA Jacks.

Circuit diagram:

Circuit diagram


  • P1 = 50K
  • P2 = 100K
  • R1 = 22K
  • R2 = 470K
  • R3 = 47K
  • R4 = 10K
  • R5 = 470R
  • R6 = 1K
  • Q1 = 2N2222
  • C1 = 2.2uF-25v
  • C2 = 100nF-63v
  • C31 = 00nF-63V
  • C4 = 3.3uF-25v
  • C5 = 470uF-25v
  • D1 = 5mm. Red Led
  • Q1 = 2N2222
  • B1 = 9v Battery
  • J1 = RCA Audio Input Socket
  • J2 = RCA Audio Output Socket
  • S1 = On-Off Switch

Using Bass Booster:

Connect your electronic guitar or other electronic instrument to input jack J1; Connect output jack J2 to your instruments amplifier's normally-used input. With power switch S1 off, key S2 so the instrument feeds directly to the instrument amplifier. With P2 set full counter-clockwise (Off), turn power switch S1 on, key S2 once, and advance P2 for the desired Bass Boost level. To cut back to natural sound just stomp down on S2 and key the Bass Booster out. Don't worry about leaving power switch S1 on for several hours of a gig. The circuit pulls less than 1mA from the battery, so battery will last many, many months.