Anyone got plans, or is it time to dig into my archives?

Bueller?

Guitar Recording: Combining Virtual and Physical
 
Amp sims and physical amps aren’t an “either/or” situation. Both have features that can make it easy to use the two together.
 
For example, some guitar players like the flexibility of amp sim effects, but want to feed an amp and speaker that actually pushes air. You can send the amp sim out to an external effect insert, drive the amp (or optionally, its effects loop input to bypass the internal preamp and tone stack), and then mic the amp. Or if you like the amp simulation but not the cabinet emulation, you can bypass the sim’s cabinet (virtually all amp sims let you do this), then using the external effect insert, drive a clean power amp that feeds your cab. Because powered speaker monitors have more or less taken over the world, it’s not too hard to find second-hand clean power amps.
 
Similarly, if you like the sound of your amp’s preamp but want the flexibility of using your sim’s amp and cabinet, you can take the amp’s post-preamp effects loop output (send), feed it into your computer’s audio interface, and run the signal through the sim’s amp and cabinet. If you want to use hardware effects, they can insert between the effects loop output and audio interface input.
 
Yet another option is to split your guitar into two paths (e.g., with a Y-cord). One drives a guitar amp (which you can mic), while the other goes “dry” into the computer. This has two big advantages. First, you’re playing through your amp, so you’re getting the “feel” of the amp and no latency as you play. Second, when mixing you can process the dry track through amp sims to get entirely different sounds. If you like these better than the miked sound, you can use them instead...or combine them with the miked sound.
 
Amp sims are so convenient, and so well-suited to working in a small home studio, some guitar players have forgotten how much a good, small amp can contribute to recording. You don’t have to record at super-high levels; you might be surprised how little difference there is coming out of a microphone at different amp volume levels. Even a practice amp can give tones that belie its small size...
 
Another trick is that if you have an open-back cabinet, you can lay it down with its back against a rug on the floor, mic it from the top pointing down, and essentially have a closed-back cabinet. However, if it’s a tube amp, make sure you’re not messing with the ventilation for the tubes. This may be something you can do for only a few minutes at a time, if at all.
 
Finally, don’t forget that the guitar sounds heard on classic recordings weren’t just about the guitar and the amp, but often took advantage of studio-quality rack mount effects to polish the sound even further. Don't be afraid to bring your full sonic arsenal to bear on creating the ultimate guitar sound.
 

Y-cord question:

I had always thought that when you use a plain ole "Y-cord" to split the output from the guitar to two different sources, that this would alter the impedance going into your amp.

What are your thoughts on this Craig?
Or anyone else's thoughts?

I'm not Craig, nor do I play him on tv (yet), but I can wax on splitters, if you don't mind.
 
Short answer, yes, impedance gets changed a bit. The resistance of the guitar coil (assuming passive pickup) gets halved (half to each split), so the ratio between guitar out and amp in gets changed. Modern amps (not line-level, whole 'nother story) expect a wide range of resistance values from the myriad pickups out in the wild, however, so there's not danger to circuitry or anything, but there could be some coloration changes depending on the ratio between guitar out and amp in. That said, you (or whomever is the guitar player) may or may not notice any sound change caused by the split other than slight decrease in gain, which is easily solved. (Or there may be no sound change at all if you ask an oscilloscope, but the player may go ahead and notice it anyway! We're like that.)  If one is using a bunch of effect pedals as part of the scenario, then coloration by a split is classed as least-of-worry. Heck, using a "budget" 30' guitar cable on stage can cause a guitar pickup to get, um, picked up differently, too. (Through capacitance change more likely than resistance change.) There's a lot of links in the signal chain that can affect the outcome, point is not to fret (haha) over all those links, but just to know about them in case you don't like the sound you are getting and you want to "fix" it. A Y split is the easy/inexpensive link to get two outputs from one instrument. If the guitar player is noticing a sound change with a splitter, then a DI with multiple outs is called for. (Although a change in sound is what the player/recording engineer is after in the first place!)

Thanks czyky.

Tip of the Week: More than You Ever Wanted to Know About Guitar Splits
 
Well since it's Friday, no one has posted a tip (but if anyone has one, feel free to post it), and I have played myself on TV, here's some more info about splitting, guitars, impedance, etc. to add to what czyky said.
 
First, as he mentions splitting affects only passive guitar pickups. If you split after effects, or an active guitar pickup, the subsequent impedance doesn't matter because the effect or active guitar pickup will have a low impedance output. This means it's only minimally affected if followed by a high impedance input, like from an amp, DI box, or well-engineered effects.
 
Second, lowering impedance will attenuate high frequencies more than low frequencies, so we're talking about a frequency-dependent level issue - not just level in general. In fact some guitarists like to feed a low impedance to take off more highs and give a "creamier" sound with distortion.
 
To my ears, following a passive pickup with a 100k impedance produces a noticeable dulling of the sound. At 250k, it's a very slight difference. Over 500k, you're not going to hear much difference, if any.
 
So why not make all direct inputs as high an impedance as possible? With really high input impedances, your cable is more likely to act like an antenna and pick up noise. A 1 Meg impedance is fine, and I wouldn't go above 2-5 Megs personally.
 
Now, about how a split affects guitar. We'll cheat and consider the impedances as equivalent to resistance, because that's close enough and I don't want to make anyone's brain explode. When splitting, the guitar sees two resistances in parallel. The formula for the value of two resistors in parallel is:
 
(R1 x R2)/(R1 + R2)
 
So let's suppose your amp has a 220k input impedance, and your interface's DI input is 1 Meg. Your guitar is seeing (1000 x 220)/(1000 +220) or 180k - not that much different than the amp by itself.
 
So the bottom line is splitting won't cause any significant degradation if:
 

• The split goes to two high-impedance inputs
• The additional split has a significantly higher impedance than the other input
• The split occurs after an active device like an effect
• The instrument has active pickups

 
 

Thanks Craig. You and czyky have helped a lot.

Now next question: What is the best way to split? A simple cut, twist, tape? Or a more elaborate soldering job?

Sounds like you need some soldering tips.

 

I saw what you did!!