michaelhanson
Herb,
 
One of the things to watch for on the Sims is your input signal.  Make sure that your getting a strong signal but not clipping.  That seems to very from amp model to amp model; how strong your pickups are and adjustment to the input on your sound card.  
 

That there is the key. For example, when you plug into an amp or even a hardware guitar pre, the input is buffered...meaning pushed a little. This changes the game dramatically and where *most* of the problems come from. There is no way to do this with a sim unless there is hardware that literally pushes the input stage of the sound.
 
The other thing to consider.....being in the guitar plug side for many years with a few companies, there are more bad guitar sims than good ones. They are so easy to make, a homeless dude that knows some code can whip up a plug, throw out a few ads that get seen by the right people, and the next thing you know, he sells 50,000 copies for $25 and he's not homeless anymore. How can you not try something with a good ad that's $25? Heck, drop that to $19.95 and that 50,000 copies thing may have just went up to 250,000....times $19.95.
 
So the quality you are getting is quite bad in some of these. Now, I seem to mention this about two times per year....so I'll mention it for the first time here again for the new people that may have joined us. Because most guitar sim programs do not give you a buffered signal going in before it even hits the plug tone stack, they are going to fall short. Let's assume that the plug we are working with today is a good one like say, Guitar Rig.
 
The first thing I do when I work with ANY plug, is to put something first in my signal chain that boosts the signal a little. Let me tell you what this fixes....
 
The first thing before we even go here though....you need a nice DI signal. Whether you go into a console or have some sort of pre or whatever into a DI or whatever you use, it has to be a good, strong, clean signal if at all possible. We can dirty it up later...but we have to start with the good stuff in the front end.
 
Keep in mind, this can be a POD set for DI with all the settings bypassed, another guitar pre-amp where you can bypass the entire unit as long as it has DI capability, dedicated Direct Boxes (which is what "DI" stands for) your interface.....whatever can get you a good signal going into the computer. Ok....moving on...
 
Ever notice these guitar sims have loads of gain, but very little sustain? Those that don't know the difference.....sustain is what allows your notes to hold out longer. This helps you to play using legato techniques as well as making for a smoother playing experience. In a hardware device, upping the gain gives you more sustain just about always. Not so for the sim plugs. You can crank the heck out of the gain and get a killer sound...but it will die out in 2 seconds.
 
The fix for this is of course a buffered input...which we don't have, so we have to sort of make one. I like to use compressors or a drive stomp box because of a few reasons. I'll explain...
 
Compression at this stage of the gain gives us a conditioned signal going into the computer/interface/sim plug. The good thing about this is, you can really get some nice sustain effects from this....but you HAVE TO have the right compressor to do this, and you'll of course need to know how to use it. Once you get the compression setting right, you open up the output a little on the compressor.
 
When you add in the sim plug and set your amount of distortion, you'll most likely start to hear some hiss unless the plug has a good gate. Even there, if you ever use a gate to the point of where it chokes off your sound and the sound dies off too fast, you are using too much gain and too much gate. It shouldn't work that way. But anyway, at this point...if the noise is hot, you back the compressor output down until the noise goes away. This along with the gain int he plug should get you some really good results as long as the plug is a good representation of what guitar tone really is.
 
Next, a simple drive stomp box. I say drive because we don't want loads of gain here. A drive/overdrive or even a Tube Screamer or Boss Compressor Sustainer can give awesome results here. The key is to not use any of the gain on the pedal at first and jack up the output knob. Same thing as the other example....lower it as soon as you get hiss. Now if you happen to need a little gain boost, you CAN turn the gain on the pedal up a little...but I've never had to do this. The output has been enough for me while using the Boss I mentioned and a Tube Screamer. (not at the same time of course lol)
 
I also recommend having any tone knobs on the pedals set for up the middle at 12 o'clock for starters. If you happen to need any of that coloration you can add it or take it away....but start up the middle.
 
You can also use tube pre-amps or any other signal boosting device. There's no way to determine what will work or what won't until you try a few things. For me so far....these are all the things I've tried to where I've been successful with good sounding plug sims.
 
Compressors: Hardware, pedals, comps built into pre-amps like a POD where everything on the POD was bypassed other than the compressor, and I've even used my 2101 (it has lo-Z outs and works as a great DI with everything bypassed) with a little compression that was in a patch while bypassing everything else.
 
Pedals: Ibanez Tube Screamer, Boss Compressor Sustainer, Boss Over-drive, Distortion (this one was a bit edgy but it worked), and a Turbo Overdrive.
 
Consoles: I've even pushed my console pre-amps a bit while using effects in-line while going into the computer with great results. My current Midas M-32 has an awesome front end that gives me some really great stuff for pre-sim processing.
 
So in my personal opinion, we always need a little something to make these things sound closer to a real guitar sound. It's also been my experience that the only cheap plug that has ever given me a good sound was the Acme Bar Gig stuff. I honestly don't say that because I worked for them....they really did give me a killer plug for free with the first versions of Shred. Other than that, the name brand stuff has been the best for me when I've had to use sims. Hope some of this helps. :)
 
-Danny