Ok if you have seen my question about MultiSim and that subject matter. The reason I am playing with a SIM program is to see if I can, or if it one can, mix and match pre-amps and power amps. I have found a few schematics I like the Pre-amps in. And some schematics I like the power amps in, and want to mix or match these together for my use or benefit. But the Sim program MultiSim is dead to me for this. LTspice will take me way in another direction, taking too many days to learn how to use it. I'm in a bit of a hurry, working against some personal dead-lines here. I have been on this site for a couple of 3-4 days, browsing, reading and searching and learning??? Yes, I have found many schematics that show similar designs and are already up and running. I have quite a few Schematics downloaded and studied to the max. But I have some other Ideas I want to incorporate that are not in there. Which will be other questions for later as I go. So hear goes the question. Looking at a schematic, lets say it is a 3 valve medium gain pre-amp with the third valve being a cathode follower feeding a james type tone stack. Now I have a Long tail Pair phase inverter feeding a Push-pull power amp, from another totality different amp schematic. What has to be math-ed out to meld these two together as far as Impedance and or coupling caps and / or things I do not know about yet? This may sound way to easy but I am just not sure of this, is it a cut and glue thing?