Thursday, January 28, 2010
This schematic reflects the changes which I made as I built my project amp. Notice the hybrid rectification method using SS diodes and the 5Y3. Fender didn't see fit to show the 6.4vac feeds to the audio tubes in their schematic, so I added them. My 60hz hum is still present. I tied a 10mfd electrolytic cap in series with the second 8mfd cap in the power supply, just after the choke, and this reduced the hum by 50%. I am now testing an old 20mfd can cap removed from one of the console TVs I scrapped. If this thing is good, I will swap it for the 8mfd that is in place now. The voltage values in red are what I actually am reading with the amp powered on. I will adjust this with resistors later. Don't forget to click on the image to see a larger version, or click on the link below to go to the actual blog.