Home Built 6L6 SE Amplifier

I built this Home Built 6L6 SE amplifier.  The output is rated at 10 watts.  It was built from a PC board circuit, a toroid power transformer, EDCOR SE output transformers and a Hammond chassis and cage.  The sound is remarkably good and there is minimal hum and noise at the speakers when you put your ear up the the speaker.

Speakers

The amplifier drives Cerwin Vega E-310 floor speakers.  The sensitivity of these speakers is 95dB.  The preamplifier is a home built unit with a tube buffer with unity gain that is connected to the power amplifier.  A Logitech Transporter is connected to the preamplifier. I added a RIAA phono peamp so I can play my record collection.

The 10 watts of tube amplification sounds really good.  It is plenty powerful and has that rich tube sound.

This was an incredibly fun and rewarding project.

Update

I changed the Chinese 6L6 tubes to JJ 6L6GC and the Chinese 12AX7B tubes to EH 12AX7 tubes.  To change the amplifier to Ultra-Linear operation. I connected the Ultra-Linear tap on the EDCOR output transformers. The toroid power transformer passed noise from power line LAN adapters I had to the speakers. I replaced the power transformer with an EDCOR power transformer. And I installed an EDCOR 10H choke.  With the addition of the choke, there is absolutely zero hum in the speakers with my ear at the speaker.

Toroid Transformer

It seems that a toroid transformer can pass some line noise through to an amplifier.  I was using some power line networking adapters for the Logitech Transporter that were generating noise that the toroid transformer passed through.  Because of the line noise I got rid of the power line network adapters. I hard wired the Logitech Transporter to the LAN.

I’ve learned that the key to low hum and noise in a tube amplifier is a good grounding scheme (not as simple as it sounds), a power supply choke, and proper filtering.

 6L6 SE Amplifier Specifications

• Power Output 10 watts per channel.
• Ultra-Linear operation.
• 23 dB voltage gain.
• Power Gain 200.
• Input sensitivity 500 mv.
• Input Inpedance 1M ohm.
• Output Impedance 8 ohms.

This Home Built 6L6 SE Amplifier was a joy to build.

Contact me if you want a radio or tube tester restored.