Kalamazoo Amp Field Guide:

Modifying Tube Guitar Amps


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.


These mods are all things I have tried, someone I know has tried, or are recommended by people who work on amplifiers for a living. 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 amp!

Most of these mods will work for any of the following Kalamazoo tube guitar amps: Model One, Model Two, or Model Twelve. They will probably work with the bass amp as well, but I've never touched one of those. Many of them will work for any tube guitar amp.


[Justin's Hot Rod] [Recording!] First up is Justin Belshe's <JBelshe@AOL.com> hot rod (safety, standard revamp, speaker, standby switch, solid state rectifier). Click on the photo for a 1156x823 JPEG (about 190kB).

Then we have Justin's Kalamazoo being mic'd in his home studio. (550x378, 42kB JPEG).

Then we have some photos from Steve (Steve762us AT-SIGN yahoo DOT com). of his Model Two. Links are to 640x480 JPEGs of about 60-75kB.

[back of amp [handiwork [circuitry [speaker out jack
Full shot of the back of the amp. It's in beautiful shape. Note the foil shielding at the top of the amp. Closer view. Nice cap job. Note speaker out jack on L bracket and quick connects on speaker lugs. Yes, that's a standby switch by the L bracket, with vacuum line over the handle. Insider information. Note the hot glued power supply caps, Orange Drops everywhere, and heat shrink. Close up of the speaker out jack with the top panel in place. No holes drilled in the panel, no grubbing around in the amp's guts!



Special thanks to Justin Belshe <JBelshe@AOL.com> (who would like to thank Tim Swartz <TimTube@AOL.com>) for lots of ideas on rebuilding these amps.

Last updated: 23 March 2006

Copyright Y2K, 2004 Miles O'Neal, Austin, TX. All rights reserved.

Miles O'Neal <roadkills.r.us@XYZZY.gmail.com> [remove the "XYZZY." to make things work!] c/o RNN / 1705 Oak Forest Dr / Round Rock, TX / 78681-1514