6L6 Stereo Amplifier
I wanted to build a good sounding 6L6 amplifier in the 20 watt range with minimal components. I believe less is more to attain good sound. With only 3 coupling capacitors involved per channel it delivers a solid 17 watts per channel at 1.5V input. Using Sovtek 6L6WXT output tubes, NOS Tung-Sol JAN 6SL7WGT preamp tubes, Edcor transformers, and regulated DC on the 6SL7 filaments.
Here is the amplifier schematic. It is based on an old AcroSound circuit. The PC boards are the same boards that I used in my 6V6 amp and were modified with a tag board posts to accommodate the AcroSound circuit. The original AcroSound circuit was a tetrode configuration which I changed to an ultraliner configuration. The original description describes a circuit that with a quality output transformer and a stable feedback arrangement permits a clean output with excellent distortion and transient characteristics. The original designed load line required a AcroSound TO-280 9K output transformer. I substituted an Edcor 8.6K which worked nicely.
The chassis is a standard Hammond aluminum chassis. After gathering your components you can layout the chassis by leaving the protective peel off plastic on. I use a fine tip permanent marker to layout the holes. You can mark your holes for drilling with a spring loaded center punch. I make the larger holes with a vintage radio punch set which does a nice job on the transformer wiring holes and tube socket holes.