X-Gain Kit

Easily add gain to your Plexi, Marshall, or Marshall-style amp! Tones like Van Halen, Dokken, Motley Crue, Whitesnake, etc. can be dialed in with our X-Gain modification. Our X-Gain Kit is the same X-Gain circuit we offer with our M50 Plexi (stock) and M100 SuperPlexi (add-on) amps. It is a switchable modification (via Push-Pull potentiometer that replaces the existing pot) that increases the gain/overdrive in most 1987 (JTM45/JMP50/1987x/50 watt), 1959 (Superlead/100 watt) circuits, or any Plexi/British style amp that has Bright and Normal channels. No chassis modifications are necessary, and no solid state components are used. Your signal path remains “all tube.”

All necessary components, wire, step-by-step instructions (via download), and wiring diagram (PDF) are provided.

DISCLAIMER: User assumes all risks. Performing these modifications will most likely void the warranty on your amplifier. Working on amps can be deadly if you do not take proper precautions. Read and follow the diagram or instructions very carefully. Basic soldering skills and basic user-supplied tools are required. If you are at all unsure of your ability to perform these modifications STOP and take your amp to a professional to be modified. You can also send your amp to us for modification. Contact us for pricing.

Beginning in 2018, instructions for modification kits are now online for your convenience. This allows us keep our prices competitive, and helps all of us reduce paper waste. Links to PDF files will be included in the order status email when the order ships, and always available in your order history. Please add grangeramp.com to your email whitelist to ensure you receive our emails. Download links can be used up to five (5) times within sixty (60) days. Please save the file to computer or similar device.

DIFFICULTY LEVEL: ADVANCED [Follow safety guidelines for working with electricity. Advanced soldering skills and knowledge of working with AC/DC circuits. Identify all terminals of electronic components using data sheets. Read resistor color codes and capacitor values, as well as identify PNP, NPN, JFET, MOSFET semiconductor devices. Measure and connect high and low voltage AC and DC. Understand advanced working of vacuum tubes. Use all functions of a multimeter. Understand Ohms law and apply to basic and advanced circuits. Work with advanced hand and power tools.]