Today, 6-20-2010, I took the amp to church to test it out in the real world. My main concern was the heat from the LM317 TO-220′s. I used the chassis as the heat sink because without a large heat sink, the LM317′s would go into thermal shutdown which caused the heaters to drop out, which effectively makes the amp stop working.
My goal was to get at least 1 hour of continuous use. I played the amp from 7:45am to 8:45am, 10:30am to 11:30am, and 4:45pm to 6:35pm. The amp was very hot, but never cut out. This is good news.
The amp circuit is a pre-version 1.2. It still has the 50 ohm power supply resistors, and it hums very loudly at volumes above 50% [volume pot at halfway mark]. I don’t expect to receive my resistors until the end of the week. I ordered them from someone on eBay so I could get them without spending a lot of money on shipping from the big suppliers.
The amp sounds great. The tone works well, and I need more time to learn the tweaks. So far I have learned that turning the high pot all the way down makes a dark distortion. I’ll need to make some video of me playing this later on down the road. I’ll apologize ahead of time for not being a very good guitarist.
(9-6-2010) I’m having issues with the tone and distortion when playing with different guitars. I’m no longer happy with my design. I am going to revise the schematic later as I experiment. I think that the AX84 project will help me determine where I went wrong. The amp has too much highs and sometimes the distortion is dirty.
(8-12-2010) The tube amp is where I like it. Check out this video to hear how it sounds. My playing is not all that, and I apologized months ago for that.
(9-5-2014) The tube amp has been changed several times since this video. Check out the latest schematic on this page: Tube Amp Builds…all in one place!