Upgrading the

Epiphone Valve Junior Guitar Amplifier

"From least to beast"

by Gearscore.com

This is a set of articles provided by GearScore.com about applying modifications to the Epiphone Valve Jr.
In other words, how to take a cheap little tube amp and turn it into a boutique like
beast of an amp, using readily available kits and minimal electronic skills.

Table of Contents

Introduction

1.1 -- What and Who?

1.2 -- Basic Safety

1.3 -- Tools

1.4 -- Audio Samples

1.5 -- Video Clips

1.6 -- Pictures

1.7 -- Very Basic Electronics

1.8 -- Basic Amplifier Theory

Mod 1 -- Re-tubing experiment

2.1 -- Sound Sample Process

2.2 -- Baseline Samples

2.3 -- How Does a Tube Amp Work?

2.4 -- Installing New Tubes

2.5 -- Mod-1 Samples

2.6 -- Mod-1 Costs

Mod 2 -- Installing the BitMO TRIO mod

3.1 -- BitMO TRIO Stage 1

3.2 -- Preparation

3.3 -- Stage 1 Installation

3.4 -- Testing the Stage 1 Mod

3.5 -- BitMO TRIO Stage 2

3.6 -- Preparation

3.7 -- Stage 2 Installation

3.8 -- Mod 2 Summary and Samples

3.9 -- BitMO TRIO Wrap Up

Mod 3 -- Installing the BitMO 10-Uator

4.1 -- What is the 10-Uator?

4.2 -- Building the 10-Uator

4.3 -- Using the 10-Uator

4.4 -- Summary

4.5 -- BitMO 10-Uator Wrap Up

Mod 4 -- Installing the Mercury Mod Kit

5.1 -- What is a Transformer?

5.2 -- Basic Circuit Changes

5.3 -- Preparation

5.4 -- Building a Shunt

5.5 -- Removing the PCB

5.6 -- Modifying the PCB

5.7 -- Installing the PCB

5.8 -- Installing the Transformers

5.9 -- Mod-4 Summary and Samples

5.10 -- Mercury Magnetics Upgrade Kit Wrap Up

Mod 5 -- Installing Mercury's 6V6 Mod

6.1 -- So What is the 6V6 Mod?

6.2 -- Circuit Changes

6.3 -- Preparation

6.4 -- Performing the Mod

6.5 -- Mod-5 Summary and Samples

6.6 -- 6V6 Mod Wrap Up

Mod 6 -- Summary and Review

BitMO

Mercury Magnetics

The Tube Store

Epiphone Valve Jr.

References

Suggested Reading