Its the original Langevin, not the JLM. I am confused by which is better and the positive and negatives of going either way. I always thought a 600ohm pot on the output is best. Then I read that a 1k variable pot on the input is best. Is there any reason why one is better than the other? I'm thinking with a variable pad on the input would give a more consistent sound since you will always be driving the input to its maximum? The JLM versino only gives -20db of variable control. So a -20db pad is still needed. I dont think you can give -40db of control. at least not with a 1k potentiometer.