6DG6GT Tube Amp Design

Rewriting History Is Fun!

In 2009 I decided that I wanted to build a tube amp. Here it is 2013, and I have now decided that THIS AMP needs to be done right.

My original build worked, but it was thrown together without a lot of thought. The circuit board was an okay design, but certainly needed many improvements. The layout of the “iron” of this amp was crappy at best. Not a single transformer was mounted on the chassis! Just imagine the amount of wiring that came out of the back. The big-bottle rectifier tube was pressed against a 2×4 board that held the cabinet together! I used a drill bit to cut a notch out of the 2×4 to keep it from catching on fire. Really, what was I thinking? I’m better than that!

This new design is not exactly the same amplifier. I’m trying out some different ideas such as a master volume, parts placements, parts values, and layout. The chassis layout is based closely on AX84.com‘s P1 layout. I am using a 16″x8″x2″ aluminum chassis from Tubesandmore.com. Some of my parts come from there and others came from Hoffmanamps.com. Some I’ve purchased recently, and others I purchased back in 2009!

I am using a design based on this Instructable (Guitar Tube Amp by GMoon) and on the AX84′s P1. I took a little from each design and changed a few things to make it my own. I have also been using info from The Valve Wizard.

Stay tuned as I work on this amp. I have parts of the turret board completed, and I have the preliminary chassis laid out. I’ve been using the guides in Inkscape to draw the designs out. This takes considerable time to complete, but I believe that it will produce excellent and repeatable results. All of this information will be available for download when I complete the build. While I’m taking great pains to ensure that the build is flawless, things do arise that make changes inevitable. I am just hoping that it won’t happen this time and that everything will be perfect.

The baby is asleep, and the 6W tube amp is quiet…

It’s 12:11am, August 12, 2010, and I just gave up doing my College Physics to replace the first stage preamp cathode bypass resistor as noted in V1.3 schematic. I sure wish it wasn’t half past midnight :). I have it on 10° or less volume, and 45° EQ, give or take a degree. I’m just guessing. I really want to crank it up to see if the tone and distortion sounds better. 9-6-2010 – It does need some circuit tweaking. It doesn’t sound good to me after all.
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