Joule Electra preamps and amps. What is your impression?

My older Sound Labs are very difficult to drive, but newer ones are easier, so I am not best to opine on that.

Just a FWIW, sbank, there are some simple mods to the Sound Labs that make them a lot easier to drive and also better sounding regardless of the amplifier. Or you can just get the new backpanels for them.

My speakers have a nomibal impedance of 8 ohm and I have no idea of the curve. Audiokinesis makes interesting speakers, I think, never heard them, though. Audio Note, Harbeth, Spendor are not for me, I guess.
Powerful SET sounds good to me.

If you have a question about a speaker, just let me know what it is and I can let you know. The requirements for our amplifiers are similar to the Joules.

 Thank you, Atmasphere. It is Michael Green Audio Revolution 80i free resonance speakers. 
You know, though it is difficult to assess while listening to youtube, that set-up - Classic Audio speakers, your amps, Purist Audio cables and some turntable sounded really good, I think. I would improve the source, though, but it's a guess. It's the video posted on Purist Audio website.

I have owned the Joule LAP 150 II, paired with VZN 100's, for 8 years. Speakers are Merlin VSM MMX. The sound is rich, warm, fast, detailed, immediate. Preamp, including phono stage, is very quiet. Amps have slight hum that is not noticeable as soon as music starts to play. Original output tubes. Replaced a couple of driver tubes. Cost of tubes is reasonable. The amps are very easy to bias. Heat from the amps is considerable - another A'Gon member commented once that the amps "could melt an igloo". Joule gear is special - the urge to upgrade melts away too!