It’s funny how a group like this can be so in disagreement about the PL400. I am in the the uk, I have a PL400-1 once part of Queen’s PA system that was given to me broken by their road manager. I have used it for home hi-fi since. Some of the comments I have seen are true, they do blow up sometimes, but there is a reason: the original design is quasi-complementary because PNP 250v 16A transistors did not exist at the time. Quasi-comp is prone to oscillation in the 100s kHz range and if the power is high and the load is low the transistors die, sometimes taking speakers with them. But this is an old problem now easily fixed. I recently rebuilt mine with a kit from White Oak Audio to fully comp using the latest MJ21195/6 transistors. It sounds good, clean with tons of bass grip. I have worked in hifi and recording studios using Neve , MCI AND SSL desks so I do know what clean means. My other hifi is vacuum tube Sansui, yes it is better in some subtle ways, but the PL holds up very well indeed compared to that. By the way, the original caps are 5900uF and white oak provide 15000uF caps to fit in the same place. The cap size is not that relevant unless you drive the amp really hard. I have neighbours, so 200W rms NEVER happens, but the transient power is there. The low impedance of the transformer secondary is more relevant than a particular number of microfarads and the PL has a good transformer.
i say, when in doubt about amplifier sound do a double-blind test, get a friend to help. You will be surprised when brand name bias is eliminated how some cheap amps thrill while expensive ones disappoint. It’s the only way to judge sound equipment fairly.
