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Hi Helmut,

as always, I am deeply appreciative of this group, of your moderation and assistance, and to LT for making it free.

having said all that, I have noticed one thing that I don't think is directly my fault in being a most NON-expert user of LTspice: when I use an outside .asy and .subckt, it sure seems to me that I get a lot more run errors of all kinds.

For example, I had to give up on using TI's TL081 op amp symbol and model, because LTspice kept insisting - but in an oddly random fashion; it wasn't every time - there was a floating node. I examined the .asy in great detail; I examined the .subckt in great detail; I examined the circuit connections in exhaustive detail; nowhere could I find any hint of why LTspice was rejecting the .asy or the .subckt, but I eventually just had to give up and use the "universal op amp" symbol and LTspice's built-in model for it. I would have used an LT op amp, but it was extremely difficult for me to figure out which LT op amp was comparable to the TL081; I eventually gave up on that as well, despite searching over and over again through the LT website (without the help of a cross-reference, of course).

So, it's weird...on the one hand, LTspice is free, this group is free, and why should I complain? I am not complaining. It's just that if I could get a spice that worked really well with a good user interface for $250, where I could use all the devices out there without huge hassle, I would switch in a heartbeat.

I almost went for Beige Bag's spice, but there were too many downsides to it. I am going to look for the "optimizer" you mention; I would gladly pay $45 for anything that would make using LTspice easier.

VB, Maturin