I’ve built four WAD 300b stereo amplifiers and serviced many more. One of my own amps is a WAD 300b stereo too, so you can tel I love the sound. An upgrade for the Wad 300b stereo I’ve now done on six 300b stereos is to add an additional choke to the power supply for the input section. This improves an already great amp, providing more bass slam, detail and dynamics. The owner brought along his Pre2 and Phono 2 for upgrades too.
The Pre 2 had been converted to a cathode follower already, which overcomes the original design’s hum issues. So this time I increased the size of the power supply choke and converted the power supply to a pseudo mono set up. For phono 2 I added cathode bypass caps to the first valve.
Overall results are a very nice improvement in SQ for the system.