Each of these designs was breadboarded,
The SPP (Simple Push-Pull) board is used to make a simplified push-pull amplifier that uses indirectly heated tubes like the EL84/6BQ5 and the 6CW5/EL86.
The SSE (Simple Single Ended) board is used to make a simplified SE amplifier that uses indirectly heated tubes like the 6L6GC, EL34, KT88 and 6550. This board is used to construct amplifiers from a basic low cost design to a high end triode mode amplifier. The choice of output tubes are all pentodes, which can be operated in triode mode, Ultralinear, and Pentode mode. This can be switch selectable from the amplifiers front panel. The output tubes operate in cathode bias mode, requiring no adjustments. The PC board was designed to be assembled by people of all skill levels. The parts density is about half of the Tubelab SE. The assembly instructions are written with this in mind. There are photographs of every step from the start to final amplifier construction. Screw connections are provided on the PC board. This makes assembly easier and servicing far easier should the PC board ever need to be removed from the amplifier chassis.
The Tubelab SE (or TSE) is similar to the third version of the Simple 45. There are only two improvements since then. A potentiometer is added across the cathode resistor of the 5842. This is used to compensate for tube variations. This allows the bias on the 5842 to be adjusted to put the tube in the most linear portion of its curves. The major improvement is the addition of the MOSFET at the grid of the output tube. This turns out to solve a lot of problems that have been present in vacuum tube amplifiers forever. For a detailed explanation of this issue, see the PowerDrive page. Some component values have been tweaked since the original design. These come from building and listening to seven of these amplifiers with a variety of different output tubes and transformers.
The 845 SE is the evolution of the O2. The SE Amp Board is being used to drive a 211 or an 845 through a PowerDrive board.
The 300 Beast is a 300B push pull amp that I designed and built several years ago. I still have the amp and use it often. It is based loosely on a design that appeared in Vacuum Tube Valley issue number 12 a few years ago. Circuit description and pictures are posted.
The Turbo Champ was the name I gave to a series of single ended guitar amps that I built over a two year period about 6 or 7 years ago. I built 5 or 6 amps, all hand wired. No two were the same, most used surplus power transformers, some from scrapped HP audio oscillators. They were all based on the original Fender Champ design. Most used Chinese KT88 tubes, although one used a 6V6.