WARNING! - Please Read this Information Carefully:

Effect Pedal modifications disclaimer

By downloading any of our mods, how-to's, guides, or videos you agree to comply with this disclaimer statement and fully realize any risks that may be involved with performing any of our modifications.

Our DIY mods should only be used by individuals that are 18 years of age or older unless accompanied by a supervising parent or guardian. 

Soldering Guns can cause serious injury if not used properly. Always take the proper precautions when soldering. Always unplug power from the pedal when performing these modifications. We cannot be held responsible if you hurt yourself, hurt someone else or destroy property. 

Please also know that we cannot be held responsible if you ruin your equipment. These mods are safe and error free when performed as indicated in their respective guide. If you follow the instructions exactly as indicated you will have no problems.

Boss®, Ibanez®, Marshall®, Diezel®, Bogner®, Danelectro®,Visual Sound®, Hughes & Kettner®, Fender®, Strat®, Stratocaster®, Tele®, Telecaster®, OLP®, Dunlop®, MXR®, and Fulltone® are registered trademarks of their respective companies. All rights reserved. All materials Copyright 2002-2006. Please contact us if you wish to reprint any of our articles or guides first. Indyguitarist.com/Brian Wampler and it's affiliates and partners have no affiliation with any of these companies.

These modifications are recommended for persons over the age of 18. If you are under 18, you should have adult supervision before attempting modifications. Please use safety precautions when modding, using tools and soldering. We are not to be held responsible if you get hurt, hurt someone else or destroy property. By viewing any of the links below you comply with the above statement and fully realize any risks that may be involved with performing any of the modifications listed. Always wear safety protection and follow safety guidelines and directions on products. Solder can pop in your eyes, burn skin, etc. Some materials used in guitar pedals can be harmful if inhaled. Batteries can explode acid on your skin and clothing. USE PRECAUTIONS, READ DIRECTIONS AND ALWAYS WEAR SAFETY PROTECTION.

Amp Modification Disclaimers

High Voltage Warning

The projects described in these pages utilize POTENTIALLY FATAL HIGH VOLTAGES. If you are in any way unfamiliar with high voltage circuits or are uncomfortable working around high voltages, PLEASE DO NOT RISK YOUR LIFE BY BUILDING THEM. Seek help from a competent technician before building, working with, or looking at any unfamiliar electronics circuit. While efforts are made to ensure accuracy of these circuits, no guarantee is provided, of any kind!

USE AT YOUR OWN RISK: THE STAFF OF INDYGUITARIST.COM, IT'S AFFILIATES AND WEB SPACE PROVIDER EXPRESSLY DISCLAIM ALL LIABILITY FOR INJURY OR PROPERTY DAMAGE RESULTING FROM THIS INFORMATION! ALL INFORMATION IS PROVIDED 'AS-IS' AND WITHOUT WARRANTY OF ANY KIND.

SOME BASIC USER TIPS

This document is not intended to be inclusive of everything out there, nor is it a substitute for common sense. Think of it as a starting point of some do's and dont's that one should keep in the back of your mind.

STANDBY - The standby switch on an amp serves 2 purposes. The first is that it allows the tubes to warm up before it is hit with the high voltage they need to operate.

The second purpose is that it will keep the tubes warm, yet allows you to mute your amp and save the tubes further by relieving them of some stress while you are not using it temporarily. It is there for a reason. USE IT whenever you fire your amp up. Turn on the amp, let it warm up for a few minutes, then flick the standby. You THEN are ready to go! When powering the amp down, however, most will agree that it is best to just power the amp off without going into standby first. It lets the capacitors in the amp drain gracefully. Note that this doesn't apply to solid state amps.

RETUBING - ALWAYS change your power tubes before they go on you. When a power tube fails it can harm other components at the same time.

How often should a person retube? There is no set-in-stone amount of time they last, since there are many factors affecting tube life. A rule of thumb, however is if you gig more than a few nights a week, you should retube your amp once a year. If your amp doesn't seem to have the power that it used to have or just sounds dull and lifeless, chances are its time to retube. Preamp tubes tend to last much longer. I recommend purchasing your tubes from Bob @ eurotubes.com, this way you won't have to rebias your amp. If you purchase tubes elsewhere, you will get better performance by rebiasing your amp. You may need to take your amp to a qualified tech for this (should cost $30-50 or so).

IMPEDANCE -- ALWAYS follow the rated impedance of your amp. If you have a selector switch, make sure it is in the proper position for the speaker load you are using. The only exception to this is if you have an amp that uses 4 power tubes and you want to reduce the power by pulling 2 of the tubes. ALWAYS double the speaker load compared to what the setting says. For example, if you pull 2 tubes on your Marshall (either the inside pair or the outside pair, never 2 from one side or the other), and you have a 16ohm cabinet, you must set the amp for 8ohms. NEVER UNDER ANY CIRCUMSTANCE RUN THE AMP WITHOUT A SPEAKER ATTACHED. YOU WILL DAMAGE YOUR AMP!

COOLDOWN -It is always a good idea to let your amp cool down for a while before moving it, or messing with the tubes. Your tubes will last longer, and you may avoid some serious burns from touching the hot tubes. Wear welding or oven gloves or use a hotpad if you must handle hot tubes!

LOUDNESS - Your ears are vital as a musician. If you are going to be playing your new creation at loud volumes, wear earplugs and/or use a good quality attenuator such as a Marshall Powerbrake or a THD HotPlate. Permanent damage to your hearing can result from not following this rule!

TUBES -- NEVER use tubes other than what the amp was designed for, unless you know that it is safe. When in doubt, check with a qualified technician.

FUSES – VERY IMPORTANT!
NEVER UNDER ANY CIRCUMSTANCE REPLACE A FUSE WITH ONE WITH A HIGHER RATING.

NEVER REPLACE A FAST-ACTING TYPE WITH A DELAYED-ACTION (SLO-BLOW) TYPE.

NEVER REPLACE A FUSE WITH ONE WRAPPED IN FOIL OR OTHER DEVICE TO DEFEAT A FUSE. THESE ARE HERE TO PROTECT YOU IF SOMETHING GOES WRONG. USE THEM!

VARIAC – Some say Eddie Van Halen made use of a variac to get his tone. A variac is a VARiable AC supply. Running an amp at a higher voltage than it is designed is a sure way to ruin the amp. Likewise running at a lower voltage can cause serious problems due to the heaters in the tubes running too cold, which can lead to cathode stripping, which leads to shorter tube life, which can sometimes cause other problems.

My advice is to not use one.

A variac is to only be used for repair and building purposes as a piece of bench test equipment.

GROUNDING - If your amp has a 2-wire power cord. PLEASE replace it with a 3-wire type! You will save yourself a lot of pain in the future. Likewise, NEVER EVER remove the grounding prong of a 3-wire cord! If you absolutely must use a 2-wire outlet, use a 2 to 3-wire adapter, and run the ground lug to a suitable ground point. Failure to abide by this CAN and WILL cost you your life!!

C. Building and repair safety

All tube amps possess lethal voltages. They CAN kill you! If you are not qualified to work on an amp, then by all means take it to a qualified technician! YOU COULD DIE IF YOU MESS UP!!!

DISCHARGING CAPACITORS - the filter capacitors in an amp will retain a charge for quite some time after the amp is shut off and unplugged. Always make sure your amp is safe to work on. See the next chapter on how to do this properly. NEVER SHORT THEM OUT DIRECTLY!

BE THE ONE-ARMED TECHNICIAN - there will come a time when you have to work on a chassis that is running. When doing so, if possible clip one of your meter's test leads to ground, and use only 1 hand to probe the circuit, keeping the other in your pocket etc. That way if you DO take a shock, your heart is not in line of the path of least resistance -in one arm and out the other. When you ABSOLUTELY must use 2 hands, be EXTREMELY CAREFUL, and use common sense, but PLEASE try to avoid these situations!

NEVER WORK WHEN YOU ARE TIRED/FATIGUED/INTOXICATED - this should go without saying, but I'm saying it anyways. When you are in any of these conditions, your reflexes are slower, and you would be more likely to make a fatal mistake. Ask yourself this test--would you be willing to take your driving test with a police officer in your car in the shape you are in? If you answer no, then DO NOT poke around in your amp!

GROUNDING - Along with fusing your power source, grounding is just as vital an issue. NEVER use a 2 wire cord with the dangerous "ground" or "polarity" switch. A 3-wire cord of at least 14AWG is recommended. The cord should be connected that there is a direct path from the chassis ground to the mains ground. FYI, the GREEN wire is generally the ground wire, WHITE is the neutral, which in MOST electrical systems is bussed to ground, and the BLACK wire is the voltage. Without a ground connection, YOU may become the path of least resistance if something goes awry.

DARKNESS -there are times that you are going to work with the lights out, so as to see arcing, or to notice the glow on tubes. Before you turn out the lights, plan what you are going to do, know your work area, and use a softer light if you have to so you don't make mistakes. To quote something I've seen elsewhere on the net, I think it was coined by R.G. Keen, but it is a statement that sticks with me, and if you can remember it as easily, all the better!: LETHAL VOLTAGES ARE JUST AS DANGEROUS IN THE DARK.

CHILDREN, PETS AND OTHERS - Your workbench is not the place to let the children or the pets play. The lethal voltages will be even more lethal for them! ALWAYS make sure you unplug your work, and even lock the room when you are away from it. Remember, death IS permanent! You wouldn't let your children or pets play in the middle of the freeway, nor should they around an open chassis.

HAIR AND CLOTHING - both can be good conductors of electricity. Keep them away! They also have a hard time dealing with power tools and soldering irons! While we are on the topic of clothing, wear the right clothes. Shorts can be bad when soldering, or other hot items, wear pants, it could save you some grief. As one who's had molten solder splashed on body parts, I know from experience, it is NOT fun. Tubes can be just as hot, USE a rag or gloves, and they too can hurt on the legs. Pants will also give you that extra margin of safety, if say you are probing the plates of your tubes for voltage, and by some freak of nature, the one you had clipped to ground came loose and hit your leg. That probe is carrying the full potential of what you are probing, which in some cases could be over 700volts!! Sure, the pants probably won't help you here, if the tip pierces them, but it will give you that extra chance! Safety goggles should be worn when using power tools. Yes, this is obvious, but many people tend to neglect this! ALSO, your ears are vital as an amp builder and a musician. If you are going to be playing your new creation at loud volumes (even 5-watt amps can be painfully loud!!), wear earplugs!

RTFM! -also known as "Read The Freaking Manual" Your tools and test equipment as well as some chemicals you may use all have warning labels and manuals. For your safety, the long life of the tools, AND the safety of those around you, PLEASE do this!! Also, use tools for their intended purpose!! A butter knife is NOT a good item to use to move insulated wires around in a chassis. Period.

D. Conclusion

Building and maintaining your tube amp can be a fun and a rewarding experience. Have fun, but most of all use common sense!!!

Your Rights and Obligations - DISCLAIMER  - You Must Read This Section
(the fine print)

By entering this site and using any circuit or description or other material presented, then you (meaning the reader of this material being yourself, or any other person that you may subsequently pass any material to) explicitly accept the following. Should you choose not to read this information, this shall be deemed implicit acceptance of these terms and conditions in their entirety.

It is believed by Brian Wampler and Indyguitarist.com and/or Brian Wampler's heirs and assigns (hereinafter referred to as Indyguitarist.com) that the designs and articles presented are either original, in the public domain or may be considered common knowledge or based thereon, and do not violate the Copyright of any other party. This cannot be guaranteed however, and Indyguitarist.com accepts no liability for loss or damages that may be imposed upon you by any Court of Law, statutory or other body, should it transpire that a similar circuit has been simultaneously or previously designed, published or patented by another party. Nor shall Indyguitarist.com be held Indyguitarist.com responsible for the failure of any project described to operate as described, loss or destruction of components or any other loss whether direct or consequential including loss of life or personal injury even if Indyguitarist.com has been advised previously of any error. It is entirely the reader's responsibility to determine the suitability of any design for the intended purpose.

The projects are presented "as is" and are believed to be without error, however this cannot be guaranteed, and it is reasonable to assume that mistakes or other errors will occur from time to time. If errors are found, please contact Indyguitarist.com and describe the error (and its consequences) so that corrections may be made.

No project or other activity referred to directly or by reference in this web site or any other as may be used or linked by Indyguitarist.com should be attempted before checking for updates or additional material that may make a substantial difference to the operation, safety or other aspect of a design, schematic or idea.

All text, diagrams, circuits and any other material presented in these project and articles pages are Copyright © Indyguitarist.com / Brian Wampler unless otherwise stated. These circuits and descriptions are available for personal use only, and may not be used commercially without the author's written consent nor may the projects or articles presented be copied or directly linked to other sites or re-published in whole or in part in any form whatsoever whether electronic or otherwise without the author's written consent. Violators will be vigorously pursued by any and all means at my disposal.

Likewise, Indyguitarist.com will not knowingly use or misuse or otherwise falsely represent the intellectual property or original ideas of others, nor re-publish or link to circuits on other sites without the consent of the author of that site, other than as a reference to my published work.  All references to the work of others is acknowledged in the article or project page where such references are made.  Any omissions should be referred to Indyguitarist.com for correction.

The material on this Internet site is made available for the purpose of providing information to the general public and is not to be taken as professional advice.

While every care has gone into the preparation of the information on this website, there are some matters of which you must be aware ...

• While we believe that the information within this site is accurate, such accuracy or reliability cannot be guaranteed. This information may change at any time

• Indyguitarist.com may not be held Indyguitarist.com responsible for any errors or omissions in the information provided

• We recommend that you review the information in any article or project and verify it before making use of any such material

• We reserve the right to change prices without notice

Any decision to implement a strategy or recommendation contained in this web site is made solely by you. No claim may be made against Indyguitarist.com or any of Indyguitarist.com's heirs, assigns or agents for any loss or damage (arising through negligence or in any other way) which you may suffer by relying on the information on this web site.

Before relying on the material, users should obtain appropriate professional advice relevant to their particular circumstances to evaluate its accuracy, currency, completeness and relevance for their purposes.

Links provided to other Internet sites are provided for the user's convenience and do not constitute endorsement of the information at those sites. Indyguitarist.com accepts no rIndyguitarist.comonsibility for material contained in any site that is linked to this or any other Indyguitarist.com website.

This book is dealing with mains electricity and is for study purposes only.  Under no circumstances should any reader construct any mains operated equipment unless absolutely sure of his /her abilities in this area. Indyguitarist.com takes no responsibility for any loss, injury or death howsoever caused resulting from, whether directly or indirectly, the reader's inability to understand and appreciate the hazards of household mains or other voltages as may be applicable to any published material.  All mains wiring should be performed by suitably qualified persons only. 

Disclaimer (cont'd)

Please Read this Carefully:

There are POTENTIALLY FATAL HIGH VOLTAGES present in the projects discussed and documented. PLEASE DO NOT ATTEMPT TO RISK YOUR LIFE in case you are not accustomed with high voltages. Look for advice from someone who is qualified. USE AT YOUR OWN RISK: ALL REGISTERED MEMBERS, MODERATORS, WEBMASTER, CONTRIBUTORS, WEB HOST, EXPRESSLY DISCLAIM ALL LIABILITY FOR INJURY OR PROPERTY DAMAGE RESULTING FROM THE INFORMATION FOUND ON our WEB SITE! ALL INFORMATION IS PROVIDED AS-IS AND WITHOUT WARRANTY OF ANY KIND.

*** SAFETY WARNING *** READ THIS FIRST!!!!!

Working inside a tube amplifier can be dangerous if you don't know the basic safety practices for this kind of work. If you aren't prepared to take the time to learn and apply the right precautions to keep yourself safe, don't work on your own amp. You can seriously injure yourself or get yourself killed. This section is not intended to be a complete guide to safety in tube equipment, just to hit the high points as refresher for those of you who have some experience. The best way to learn the requirements and practices for safety in tube equipment is to find someone who will teach you one on one.

BASIC REQUIREMENTS

• UNPLUG IT FIRST Pretty self explanatory. Do not, ever, ever, leave the equipment plugged in and start work on it unless you specifically intend to make some live-voltage measurement. Leaving it plugged in guarantees that you will have hazardous voltages inside the chassis where you are about to work. This is like setting a trap for yourself.

• LET IT DRAIN If the amp has been turned on recently, the caps will still have some high voltage left in them after the switch is turned off. Let it sit for 10 minutes after you turn it off.

• SUCK IT DRY AND LEAVE THE JUMPER WIRE CONNECTED WHILE WORKING ON IT high voltage electrolytics caps can "regrow" voltage like a battery sometimes. Really. ) Remember to remove it when you finish your work.

• TEST IT Take your multimeter and ground the (-) lead. Probe the high voltage caps and be sure the voltage across them is down, preferably to less than 10V.

• BUTTON IT BACK UP FIRST Take the shorting jumper out. Put the chassis back in the cabinet, making sure all of your tools, stray bits of solder, wire, etc. are out of it. You don't have to actually put all the screws and so forth back in if you believe more work might be needed, but make sure that the chassis is sitting stably in the cabinet and won't fall out. At the end of a listening test, either continue buttoning up if you're done, or go back to UNPLUG IT FIRST.

NO GUARANTEE

These mods are all things I have tried, someone I know has tried, or are general informational guidelines. Nevertheless, if you try any of these, you assume all responsibility for anything that happens, whether the amp explodes, you get zapped, or the amp suddenly increases in value because everyone falls in love with it. The glory, the pain, whatever, they're all yours. If you can't live with that, don't mess with the pedal or amp!