Eric Beeman gave me his crate tube amp to modify into something a little more palatable(the black amp in the first pic).  The parameters were low cost, small, and light weight.  He wanted to get a warmer clean sound out of it as well as a more usable overdriven sound.  Beside that he gave me free reign.

I looked up mods for the amp online.  I found a good resource at guitarnutz.com.  One of the problems with this crate amp is that it has a solid state pre-amp before the first pre-amp tube.  When you turn up the gain, the solid state section would overdrive before the tube.  This results in a harsh buzzy overdrive.  The guitarnutz page had instructions on how to fix this.

I removed and replaced a few capacitors and resistors, re-routed some wiring and added a pot to control the drive of the power tube.  I also rewired the tone control to work like a normal one instead of the ‘mid scoop’ it actually controlled.

As part of the fix we needed to get a 12AY7 pre-amp tube instead of a 12AX7.  This tube has lower gain properties and will not overdrive the next stage int he amp as much.  Since we needed a new tube anyway, I ordered that one and a new el84 tube from Dave’s tubes.  I got JJ brand tubes which are generally considered good solid dependable tubes.

The next part of the eqation was a new speaker.  12″ speakers are very common for guitar and could definitely give some improved warmth over the stock 6″.  Since price was a factor, we went with a Weber signature series.  It has a ceramic magnet for a little better low end and an overall warm voicing.

Now for the cabinet a small size was necessary.  I used baltic birch for the construction and a semi closed back to tighten up some of the low end. (This speaker does not like closed back)

After an attempt at staining the cab for a natural finish, I decided tolex would be a better option….

The result is great.  While the speaker still needs to break in, it produces much warmer tones.  The overdrive in the amp is very pleasant and highly controllable via the two gain controls.  When the speaker settles in I think this will be a very good amp for the money.