What do the concentric bass and treble controls do?

The concentric controls let you shape both low and high frequencies simultaneously without taking up extra panel space. You adjust bass and treble independently with a single rotary encoder, giving you precise EQ sculpting for dialing in exactly the tone you need for any session or performance.

What is the Slap Switch and how does it work?

The Slap Switch is a push-pull mechanism integrated into the volume control that toggles between two preset EQ voicings on the fly. Two trim pots on the circuit board let you fine-tune each preset, so you can switch between two distinct tonal characters instantly during performance without adjusting knobs.

Does this work with my passive pickups, and what about battery life?

Yes—the STC-2P is engineered specifically for passive pickup systems and preserves their natural character while adding active EQ control. It runs on a single 9V battery with an included clip; an optional 18-volt configuration is available if you need increased headroom and dynamic range.

Will this fit in my guitar's control cavity?

The circuit is compact and fits comfortably in standard control cavities alongside three control knobs (bass, treble, volume, and blend). It requires space for one 9V battery; measure your cavity depth and width against the circuit's 4.00" W × 1.50" H × 9.00" D dimensions to confirm fit before installation.

What comes in the box and do I need to solder?

The STC-2P includes a pre-wired harness with high-quality potentiometers, knurled black dome knobs, and a battery clip ready to install. You will need to solder the harness to your guitar's existing wiring; the trim pots on the circuit board handle preset adjustments, so no extra soldering is required for fine-tuning.

Seymour Duncan STC-2P 2-Band Tone Circuit For Passive Pickups

The STC-2P is a compact, high-headroom active preamp engineered to unlock tonal control in passive pickup systems without sacrificing signal integrity or introducing noise. Its intuitive control layout—combining concentric bass and treble controls with dedicated blend and volume knobs—gives you surgical precision over frequency shaping during tracking and mixing. The proprietary Slap Switch adds production flexibility, letting you toggle between two preset EQ voicings in real time across multiple takes or sessions.

Electronics & Control Layout

Built on a pre-wired harness with high-quality potentiometers and knurled black dome knobs, this circuit delivers clean, artifact-free operation across the entire frequency spectrum. The Slap Switch—a push-pull mechanism integrated into the volume control—works alongside two trim pots on the circuit board for fine-tuned preset adjustments, giving you instant access to two distinct tonal characters without rewiring or offline adjustments.

Power & Installation Requirements

The circuit runs on a single 9V battery and fits comfortably in standard control cavities alongside three control knobs, making retrofit installation straightforward for home-studio builds. An optional 18-volt configuration is available for users who need increased headroom and dynamic range for high-output pickups or demanding recording scenarios. The included battery clip ensures secure, rattle-free power delivery during extended sessions.

Key Features

High headroom, low-noise 2-band active EQ preamp for passive pickups
Concentric bass and treble controls for simultaneous dual-frequency shaping
Master volume control with integrated push-pull Slap Switch
Dedicated blend control for pickup mix management
Pre-wired harness with high-quality potentiometers
Proprietary Slap Switch with two trim pots for preset EQ adjustments
Operates on single 9V battery; compatible with 18V configuration
Includes battery clip and knurled black dome-style control knobs
Requires 3 control knobs and single 9V battery space in control cavity
Weight: 1.20 lbs; Dimensions: 4.00" W × 1.50" H × 9.00" D

The STC-2P delivers transparent, articulate tone-shaping control while preserving the character of your passive pickups—an ideal upgrade for producers and engineers seeking serious EQ flexibility without a complete electronics redesign.

Condition	New
Country of Manufacture	United States