I am playing through a JTM60, and i like the sound of this amp. a friend gave me a pair of new JJE34L's, suggesting they would much improve the mid-to-low end response. i am running sovtek EL34G's now, which i read negative opinions about, but i have nothing to compare them to, so i will give the JJ's a try (i REALLY liked what JJ's did for my fender). my question: should i rebias with the new tubes? i am familiar with the biasing process from re-tubing my fender, so no biggie there, except i am not familiar with the test points on the JTM are. thanks in advance for any suggestions.