Gamma PreQ
Acoustic Guitar Preamp, EQ & Boost
Designed for Acoustic Guitar
The Gamma PreQ was designed specifically for acoustic guitar, although it will work for any acoustic instrument (but not bass). It has plenty of clean gain as a preamp, a plethora of EQ options, and a dedicated boost.
It's quieter than most acoustic preamps and offers more EQ options. It's not as great as Grace Designs' ALiX (which is awesome), but it's close!
This is a DIY assembly you put together yourself. While this shouldn't be your first build, there's nothing particularly challenging about it other than its size (~150 total parts). Read the BOM and Build Notes carefully to comprehend the scope of this project.
Features
- Gain, Volume, Boost: +25 dBu, +17 dBu, +6 dBu respectively
- -∞ for Gain , Volume
- HPF / Notch: 68–440 Hz (Butterworth 2nd order)
- High Pass @ -12 dB/octave
- Notch: 5 < Q < 15
- Low Control: @ 100 Hz +/- 12 dB
- High Shelf: @ 4 kHz +/- 12 dB
- Parametric Mid: +/- 9 dB
- Low Range: 103 – 880 Hz, 0.5 < Q < 5
- High Range: 435 – 3700 Hz, 2 < Q < 20
- Frequency Response: 68 Hz – 20 kHz
- THD: < 0.02 %
- Input Power: < 200 mA @ 9 VDC
- Internal: +/-15 VDC — for plenty of headroom
- Input Impedance: 3.3 MΩ (user defined)
- Bypass: True Bypass or Mute
- Internal switch
Pricing
- PCB set only (see pictures above): $25 + $8 shipping
- Parts kit (no enclosure/knobs): $100 + $10 shipping
- + $10 for 1 - LM4562
- + $10 for 3 - OPA4134's
- Payment via Venmo or PayPal
Documentation
Reference documents for building and tuning the Gamma PreQ.
Interested?
If you have any questions about the build, OR
To order PCB set or a parts kit: