So voila, it's a can within a week I instaled the little "small lights" on my JMP 2204. In fact I read that the lamps (preamp) equipped with large plates such as LPS offer a better attack, one can bite. Well, I quite agree. For my part I would say that these lamps give a better definition of the saturation of the preamp when we want it to be important and they actually give a little more aggressive. Atention! do not expect to transform your old Marshall Mesa! I could compare the 12AX7 WA has the same brand, but chages, although subtle, are exactly what I wanted: I play a Fender Tele and two boosters (Seymour Duncan and mxr) to boost the signal from the grate without altering the personality. Result, 12ax7WA struggled to manage the level of output generated by the huge boost '(low CRADA). LPS seem perfectly handle it, so much so that I can mount the preamp knob to 9 without vomiting in my rooks (impossible with the WA).

In short: Ideal if you like the old vintage sound very full and you are a fêllés may like me to want the power of a LessPaul with the personality of a Teloché. I put 9 because I can only element of comparison.

So sorry my case is not too general but it's experience!