Surveyor

The Electronic Audio Experiments Surveyor is a compact re-interpretation of the Intersound IVP (Instrument Voicing Preamp), a cult classic and long discontinued rackmount preamplifier. The IVP is best known for its distinctively clangy tone and harsh attack at high treble settings—especially in conjunction with an aluminum neck guitar, single coil pickups, and full range speakers.

The Surveyor features a unique, transformer-based “Tube Voice” distortion generator that is highly responsive to the frequency content of the input signal. This is achieved by placing a two-band Baxandall EQ before distortion is applied—the complete opposite of most drive pedals. Using this method, gain may be selectively applied to a specific frequency band: boost the treble for that signature clang, or maximize the bass for fuzz overload. This variety of saturated textures transcends genre labels.

Controls:

• Level - overall volume, with more than enough range for line level output or to overdrive a tube amplifier

• Gain - amount of overdrive/saturation equally applied to all frequencies; highly interactive with the Bass and Treble settings

• Bass - pre-gain low shelf boost/cut, +/-12dB @ 100Hz

• Treble - pre-gain high shelf boost/cut, +/-12dB @ 3KHz

• Hi/Lo (switch) - sets the range of the gain control. In the Lo setting the gain range is -15dB to +12dB, in the Hi setting the gain range is +9dB to +36dB.

Changelog

• V2.5 (Spring 2024)
  - Minor electrical adjustments
  - Simplified bypass circuitry to remove microcontroller
  - Minor artwork/print adjustments

• V2-V2.4 (2021-2022, incremental changes)
  - New mechanical format (changed enclosure shape, knob spacing, jacks, etc)
  - Added power supply over-voltage shutdown circuit and ESD protection
  - Added Hi/Lo toggle to increase gain range

• V1
  - Original release

Additional specs:

• Bypass: Relay switching with true bypass

  Input impedance @ 1 Khz: 500kΩ

  Output impedance @ 1 Khz: 2kΩ

  Power: 9V DC, 2.1 mm centre negative barrel. The current draw is 75 mA.

  We recommend a regulated, isolated power supply rated for 100 mA minimum. The PSU input is protected against reverse polarity and over-voltage up to 24V. Our pedals do not accept batteries.