Conrad johson versus lamm

I guess you meant are NOT powerful enough...right?

I believed you must have tried the two impedance settings in the back of the Lamm M1.1. 1-6 and 8-16 impedance settings.

I have a Revel Salon 2 and tried it with the LP 140 and it didn't work quite well. Now I have the Lamm M2.2 that works great with the Salon 2. I know that the Confidence is a bit more efficient than the Salon 2, but it still dives deep to around 3 ohm. I doubt you would gain a lot with the LP 140 with the Confidence.

Perhaps the LP275 monos work better with the Confidence.

I found the CJ Prem 140 to be very solid state sounding and I never could connect with it.

You will need more power to effectively drive C4's with tubes. I'd consider a good solid state amp or a better and more powerful tube amp.

Have you had problems with clipping, or does it just "seem" like a logical change? I've owned the Lamm pair and used them to drive Dynaudio Evidence Temptations and never felt that they gave out of steam. But I'm not a headbanger.