20 WPC Vacuum Tube Amplifier

I made the following updates in June 2020:

• Replaced LED with Bivar MPC5ADW6.0 and 820 ohm (I think) resistor
• Replaced power entry jack with Schurter 5120.0303.0 PEM filter
• Removed volume control
• Moved bias select switch from back to front (where volume control used to be)
• Replaced signal wire with Mogami W2330