TL072 High-Impedance Guitar & Microphone Preamp Module | 1MΩ Input | 10x Gain | 12V Single Supply | Pedalboard Ready

📋 Overview

The TL072 High-Impedance Guitar & Microphone Preamp Module is a compact audio preamplifier designed for electric guitars, bass guitars, microphones, and other high-impedance sources. Built around the Texas Instruments TL072 dual JFET operational amplifier, it delivers clean 10x (20dB) signal amplification with low noise and a flat 20Hz–20kHz frequency response. The module operates on a single positive supply (+9V to +15V DC) and includes an onboard potentiometer for output level adjustment — making it ideal for DIY pedal builds, instrument modifications, and recording setups.

⚠️ Important: This module accepts unbalanced audio input only. The microphone connector uses two pins: Ground (tip) and + Signal. Do not connect balanced audio sources directly.

⭐ Key Features

• High Input Impedance: 1MΩ — ideal for passive pickups and microphones
• Fixed Gain: 10x amplification (20dB)
• Single Supply Operation: +9V to +15V DC (12V recommended)
• Low Noise: JFET input stage minimizes noise (<10µV typical)
• Unbalanced Input: Microphone connector accepts Ground (tip) and + Signal only
• Onboard Volume Control: Potentiometer adjusts output level
• Wide Frequency Response: Flat 20Hz–20kHz with no tonal coloration
• Low THD: <0.01% at 1kHz
• Compact Design: Easy integration into pedals, instruments, and enclosures

📊 Specifications

📌 Pin Configuration

3-Pin Header (Power & Output)

• +VCC/+V: Positive power supply (+9V to +15V)
• GND: Ground/common reference, shared with +VCC and VOUT
• VOUT: Audio signal output (low impedance)

Microphone Connector (Audio Input — Unbalanced Only)

The 1/4" microphone connector jack accepts an unbalanced audio input only using two pins:

• Tip: Ground
• + Signal (Sleeve): Audio signal input

Do not connect balanced (XLR or TRS) sources directly — this module does not support differential/balanced input.

🔋 Power

Voltage & Current

• Minimum: +9V DC
• Recommended: +12V DC
• Maximum: +15V DC
• Current: 5–10mA typical, 15mA maximum

Single-Supply Operation

This module operates on a single positive voltage only — it does not use dual ±V supplies. The circuit creates a "virtual ground" at approximately half the supply voltage. Input and output signals are AC-coupled via capacitors, and DC blocking prevents DC offset from affecting connected equipment.

Power Supply Options

For Guitar Pedals:

• 9V battery (6F22/PP3)
• 9V or 12V DC wall adapter
• Regulated power supply (preferred for lowest noise)

For Instrument Integration:

• 9V battery compartment
• Internal regulated supply from instrument's existing power

Power Quality

• Use regulated DC supplies for best performance
• For additional filtering, add 100µF electrolytic + 100nF ceramic capacitors across power pins
• Avoid noisy switching supplies without proper filtering

⚠️ Important Notes

• Polarity Warning: Verify power supply polarity before connecting — reverse polarity will permanently damage the TL072 IC
• Unbalanced Input Only: The microphone connector accepts Ground (tip) and + Signal only — do not connect balanced audio sources
• Maximum Voltage: Never exceed +15V DC on the power supply input
• Static Sensitive: The TL072 is static-sensitive — use anti-static precautions when handling
• Clipping with Hot Pickups: Active pickups and high-output humbuckers may clip at 10x gain — reduce input level or use a 9V supply

🚀 Getting Started

Step 1: Power Connection

1. Connect ground first — solder black wire to GND
2. Connect positive supply — solder red wire to VCC/+V
3. Optional: Add bypass capacitors (100µF electrolytic + 100nF ceramic across power pins)

Step 2: Input Connection

This module accepts unbalanced input only:

1. Use shielded cable for the input connection
2. Microphone connector: Connect Ground to the tip pin and audio signal to the + Signal pin
3. 1/4" jack: Connect signal to the jack sleeve and ground to the tip
4. Connect the cable shield to ground at the input end only
5. Keep input wiring as short as possible

Step 3: Output Connection

1. Use shielded cable for the output
2. Connect signal wire to the VOUT pin on the 3-pin header
3. Connect shield to ground
4. Route output wiring away from power wiring

Step 4: Testing

1. Visual inspection: Check all solder joints
2. Continuity test: Verify no shorts between power rails
3. Power test: Measure voltage at VCC pin (+9V to +15V)
4. Signal test: Input a test signal and verify amplified output

🎯 Applications

Guitar Pedal Building

• Clean Boost: 10x gain for driving amps and pedals harder
• Buffer: High-impedance input prevents tone loss in long cable runs
• Preamp Stage: Amplify weak signals before effects processing

Instrument Modification

• Passive Guitar/Bass: Install in the instrument cavity with a 9V battery
• Acoustic Guitar: Amplify piezo pickup signals
• Vintage Instruments: Add modern output levels to older instruments

Microphone Preamplification

• Dynamic Microphones: Boost low-level mic signals via the microphone connector (unbalanced only)
• Contact Microphones: Amplify piezo contact mic elements

Recording

• DI Enhancement: Boost signal level before an audio interface
• Re-amping: Amplify recorded tracks for re-amping setups

Other Uses

• Headphone Amp Driver: Signal boost for headphone amplifier circuits
• Multi-Effects Input: Optimize signal levels for digital effects processors

📄 Documentation & Resources

• User Guide: TL072 High-Impedance Guitar and Microphone Preamp Module User Guide
• TL072 IC Datasheet: Texas Instruments TL072 Datasheet (PDF)

Sold and supported by Envistia Mall. Ships from the USA. For wiring diagrams and troubleshooting, see the User Guide link above. The manufacturer and Envistia LLC (dba Envistia Mall) are not responsible for any damages or losses resulting from the use of this product. Always follow proper electrical safety practices when working with electronic components. Specifications are based on manufacturer data and are subject to change without notice.