Hi! I just finished a micro JMP : 1959 preamp and then micro-JCM PI and power section (thanks rob for your website!!!) It sounds really good but something's strange though. Presence control has little to no effect at all... On this amp NFB is fed from the 16ohms tap and attenuated by a 22k. My guess is that with 22k the amp has about no NFB at all because of the very small output voltage (only 1W so maybe 1 or 2 V RMS?) I will experiment with lower NFB value but i'd like to hear what you think ?