Welcome to the fantastic world of tube amps. First of all a word of warning: modding tube amps is a lot of fun as long as you know what you are doing. Tube amplifiers contain potentially lethal, high voltages even after they are unplugged, that may cause personal injury or death. Do not attempt to repair, modify, or work on any amplifier unless you are absolutely certain you know what you are doing. Most of the mods here are very simple to do but very helpful, so we are sure you will have fun with the stuff here.

 Adding a speaker-out jack to any amp (PDF, 10kb)

If your amp has no speaker-out jack it is a good idea to add this option. It will give you the freedom to also plug in an external speaker cab. Thanks to MEO for working out this things.

 Adding an external speaker-out jack to any amp (PDF, 15kb)

This is a quite better solution because you donīt have to disconnect your internal speaker to plug in into an external cab. Thanks to MEO for working out this things.

 Adding an additional "line out" jack to any amp (PDF, 119kb)

If you have an amp with no "line out" or "preamp out" jack but it does have an "external speaker out" jack you can use this simple circuit to build your own "line out" system.

 Adding a standby-switch to any tube amp (PDF, 16kb)

If your tube amp has no standby-switch this is an interesting project for you. A standby-switch makes some things easier and can help you to extend the lifetime of your power tubes. Thanks to MEO for working out this things.

 How to cascade several amps (PDF, 11kb)

The technique of "slaving" amps allows you to use the same amp for every situation (studio, all kind of stages ...). Here is how to do it right.

 Get that classic Fender tone out of any Fender tube-amp (PDF, 111kb)

Do you have a Fender tube amp and want this classic Fender sound ? Here is what to do .... It works for all Fender, Music Man and similar tube amps from all decades, give it a try.

 Modding a Fender 59ī Bassman reissue amp for vintage tone (PDF, 33kb)

The Fender 59`Bassman (5F6A model) is for sure one of the holy grails of tone. The original units are very expensive but worth the money. Fender also released a reissue model of this amp which is a fantastic sounding guitar amp, but not at all a 1:1 copy of the original. Here is a step by step guide to mod the reissue for a big, warm vintage tone, very similar to the original amp. All the necessary circuit drawings for this can be downloaded here.

 Getting more distortion from an old two-channel tube amp (PDF, 43kb)

This is a very effective and simple way to get a lot of distortion out of any old-style two-channeled tube amp without any fancy stomboxes or internal modifications of the amp.