Revered for its tight, fast response and wide tonal flexibility, the GAMMA preamp takes the beloved AG sound and places it in a compact pedal. The GAMMA preamp features a 4-band EQ and foot-switchable broadband“deep” and “bright “controls for added depth and presence. Its 18-volt operation provides plenty of headroom ensuring your sound stays clean and transparent. It also features a built-in headphone out and aux in, for silent practicing, as well as a DI with pre/post and ground lift controls. The GAMMA preamp is a must-have for any bassist looking for a clean and transparent preamp with all the controls needed for sculpting their sound.

Analog preamp circuit inspired from the AG 700 amplifier

• 4-band EQ with treble, bass, low midrange, and high midrange controls

• Foot-switchable, broadband “Bright” and “Deep” EQ controls

• DI out with pre/post and ground lift controls

• 1/8” aux-in and 1/8” headphone out for silent practice

Functions:

Top Panel:

Gain - Controls input sensitivity level

Treble - +/- 14 dB @ 4 kHz

Bass - +/- 17 dB @ 40 Hz

High Mid - +/- 14dB @ 800 Hz

Low Mid - +/- 15 dB @ 300 Hz

Volume - Controls output level

Engage - Toggles between on/bypass (blue LED indicates on)

Bright/Deep - Toggles through broadband “Deep”, “Bright”, or “Deep + Bright” (blue LED indicates on) The

frequencies for the boosts are:

Deep: +6 dB <250 Hz, shelving Bright: +6 dB >3 kHz, shelving

Headphone Mix - Controls mix of bass signal and aux-in in headphones

B. Top Side Panel:

In: 1/4” input

Aux In: 1/8” aux input for music device

Out: 1/4” output

Headphones Out: 1/8” headphones output

DC IN: 18v. This is a standard 2.1mm DC jack. The center terminal polarity is negative.

 

C. Left Side Panel:

DI Out: XLR balanced DI out

Pre/Post Control:

 Pre: Your signal goes to the D.I. XLR output before your Gain and EQ settings

 Post: Gain, EQ, and Master settings will be sent to the D.I. XLR output jack.

Ground Lift Control: If there is a hum when using the D.I, there may be a ground loop. In many cases,

pushing in the Ground/Lift button can fix this problem.

 D. Specifications:

Current consumption:............................. 36 mA

Input impedance: ..........................................1mega Ohm

Output impedance: .........................................1k

External DC Power: ………………………18v DC

 E. Headphone out:

The AG Preamp features a headphone out for silent practice. Use the Aux-In 1/8” for connecting your

laptop, phone, or audio source and the Headphone Out 1/8” out for your headphones. To adjust the

overall headphone volume, use the main Volume control. To adjust the balance of your aux-in to

headphone mix, use the Headphone Mix control just above the Volume control.