Hi Charlie,
The 55N-->N+ took me a couple of evenings of soldering (and I tend to work very slowly). Setting the bias was another evening or two (since I check for 55mv quiescent multiple times, to be sure that I've got a stable and repeatable reading). Overall, the N+ upgrade is by far easier to do than the initial Nirvana upgrade. My DC offset was still good, i.e., I did not have to change any resistor values (other than those in the N+ upgrade) to reduce the offset. Break-in is really strange, just as everyone else has said many times.
The sonic impact of the N+ upgrade (in my system, caveat, caveat, caveat) was the least subtle change to my amplification I've heard since I swapped out my old NAD 7020 for my first AKSA 55. The improvement was stunning. To calibrate that statement, sometimes I can hear changes due to speaker wire or interconnects, often I can't. I can usually hear changes in PS caps, and I can hear the effect of soft recovery diodes in the PS.
I think lifting traces can often result from either applying too much pressure with the soldering iron when removing old components, or not getting all the old solder removed... then there is a small solder bridge to the old component, and when you try to remove it, it won't come loose. If you just pull harder, you will probably rip the trace.... instead, gently heat the connection and wick some more solder away. Sometimes the trace can pop when you put the new lead through the PCB... the lead catches the underside of the trace and pops as you push the new part home. The solution here is to feel the part as it goes in, and if it catches, play around until it goes in smoothly. Go slow, feel what you are doing, and--if you can--use a stand-mounted illuminated magnifying glass to watch what you are doing too (these are often pricy, but if you keep looking, you might find a decent one for $25-40).
You can definitely do this. The risk is minimal (if you are patient, the risk can be zero). The sonic reward is huge. Go for it!
Peter
