ColonelForbin

Check out Mission Engineering. You going with rack or floorboard Helix? Mission has a toe switch version, but only works for the Helix rack. The regular Mission L6 ep1 works as exp pedal with any Line6 gear, Helix rack & floor, HD500, etc.
 
http://missionengineering.com/?product=ep1-l6
 
http://missionengineering.com/?product=sp1-l6h-line-6-helix
 
http://www.sweetwater.com/store/detail/EP1L6Bk
 
http://www.sweetwater.com/store/detail/SP1L6H

That is the same way I connect my rig with my band; we use the M20d to record our rehearsals and do sound for our gigs. I only have the mixer and two L2's for the monitors, so we have to run the main outs to a PA or house sound, but works pretty well.
 
Here's the key: the DT25 XLR out is MIC level. You need to go to the channel in the M20d and increase the gain. Easiest way to do that is tap the little icon that shows channel level ,and it will pop up the various options - took me a while to discover that one - and the red one is trim ( I think brown is panning?)
 
Increase the gain a bit- treat it like a mic signal, which requires some gain to get up in level.

Yes, should be pretty straight forward. Make a two amp model patch, make both amp models approximately the same, and pan them hard left and right in the mixer block. Put the pre amp model FX you intend to use on both before the amp models. Make sure if you use any FX after the amp models to put them before the mixer block.
 
The mixer block needs to be the last thing (before the looper), thus preserving the left / right panning.
 
You could try some basic tricks like, use a delay set to 100% mix on one of the amp models, after the model before the mixer, and set the time to the shortest possible amount. You can do a similar trick using a pitch shifter, by adjusting the pitch up or down a few cents.
 
Anything to take the same basic sound and make it slightly different.
Record the two outputs from the HD500 as dual mono, rather than as a stereo file.
 
Others will likely have some other good ideas for what you can do to fatten up the sound. But that's the basic concept.
I run dual amp models into dual amps, same basic concept.
 
One note, you can place stereo effects after the mixer block If you place mono effects after the mixer block, it sums the stereo signal to mono, which defeats the purpose of panning hard left and right.

I *think* I figured this out; while driving to work today. It just occured to me that, if you have a patch which:
 
1. has no FX in the slots before the amp models
2. has two amp models, panned hard left and right
3. set the input settings to different sources; as I did...
 
Then, it sees two amp models and two input sources, and one of the input sources in my case was empty (I had nothing plugged into the guitar in)
 
I had set input 1 to variax, and input two to guitar - old habit from running single amp models...
In doing so, I muted one amp by not sending it any signal!
 
:)

I'd have to say "maybe"... I think what the L2m would offer you, without substantially changing your current rig, is a dedicated floor monitor for your HD500, because you could still feed the FOH mix with the stereo XLR from the HD500 - while connecting the L6Link to the L2m. I haven't messed around much with using my L2t as an amp with my HD500; but with that route I would lean more towards adjusting some of the EQ as the other posters suggested, and maybe use a combination of your in-ear for the band mix, and the vocals, and use the L2 as your primary guitar monitor. I would imagine if your patch cuts well and sounds right coming out of an L2, it should also sound pretty good in the main mix.
 
For me, I realized I liked the more 'traditional' guitar amp sound as my monitor. The sound of actual tubes and power amp interaction, paired with a nice Celestion speaker. Nothing against the full-range, flat-response that the HD500 is capable of; it just "felt" right coming through the DT25, in ways that I didn't get previously. It may just be due to laziness on my part; instead of spending the time sculpting my HD500 patches, I just let the DT25 do what guitar amps do, which in a lot of ways, creates a natural pleasing to the ear sculpting of the tone. Alot of the "high def" audio we get used to hearing in live broadcast, studio recordings, live concerts - much of that is occuring way, way "post" - it's not originating on stage, it's from behind the mixing console, with plugins, multi-band compression, stereo expanders - all of the stuff you can do with Pro Tools to make your mix pop, is what professional audio engineers are doing to a mic on an amp, and a vocal, and a snare mic, kick mic, bass DI - if the stage mix was that hi-fi, I think it might be a bit of a mess. That's to me, why there are two mixes - main and monitor.
 
A total aside to that, at some point along the way, Phil Lesh decided it would be a cool idea, along with the board recordings they were making (Betty Cantor, best of the best at making that mix!) Phil decided they should record the monitor mixes. Very interesting side-by-side listening experience. Two different world of sound.
 
Which sort of comes full circle, to my take on it, which is - the pairing of the DT25 + HD500 is a heck of a powerful amp switching tool. First and foremost, that is the #1 most valuable function it offers. That you can integrate various external pedals into the FX loops of both, even while utilizing the L6link, makes it that much more functional. In some ways, I think alot of us get hung up on "stereo", when in most cases, live at least, stereo is a detriment to the tone, rather than an enhancement. For me, the DT25 forces me to think "mono", and get through the hurdles of programming, and narrowing the "Way too many choices" panic reaction effect that working too much with tweaking this gear can cause.
 
At this point, I am even considering going to the alternate FS setup, and limiting myself to like, four main patches, and then possibly, a couple banks following that pattern. Like, 1A, 1B, 1,C, 1D; 2A, 2B, 2C, 2D, and set them up with the same footswitch assignments in all patches - make the 'D' bank acoustic JTV friendly (do the radatats option, where you define two amp blocks, just select one amp model, leave one blank, turn down the actual amp model all the way, use the blank channel to pass signal direct to the DT power amp, and select a good typology and class to best reproduce JTV acoustic models - he's got a more detailed explanation floating around in various posts - worth a try, check it out - works quite well) - anyway, 'C' bank is lead, 'B' bank is crunch, 'A' bank is clean.
 
I'd choose a few of the amp models I like the best, and maybe switch each patch according to a good amp choice for each intent. I use the Plexi alot, for almost everything, but the various other Fender and Marshall models all sit in the right vibe for where I end up going. I've been adding external (Keeley) pedals to the mix, to free up more FS settings - which is why I mention the FS programming.
 
How many people prefer having instant access to four patches, and using just the four FS switches?
I've almost always done that; and very rarely bothered to program the full bank of 8 FS settings - where you use the toggle up/down bank switches on the left side to trigger a patch change. Leaning heavily toward that concept; rather than programming out each patch to change so many multiple settings, or be "just right", I lean toward "controlled chaos", where the programming ensures that any given effect on/off, in conjunction with most any other efffect on/off, creates a decent tonal combination. I'd rather be choosing between on/off for three or four external pedals, and 8 FS switches, to have full control over each and every effect block in each patch. Sort of 'back to the drawing board'. Alot of that vibe is coming to me from interacting with the sound, from the DT25.
 
It's a subtle distinction, but they key is - your amp sound is your amp sound; and the sound of a mic on that amp is a different thing. It's up to you to make your amp sound right to get your tone - it's up to the mic on your amp to get that sound to the audience or the recording. While the HD500 does a great job of both of these things - it cannot do them both at the SAME TIME. Meaning, you are either listening to the "control room" version of your amp with a mic on it (Studio Direct) or you are listening to your "Actual Amp" sound - Combo/Poweramp, as in using the L6Link to a DT25. I ended up realizing I preferred the sound of the amp to the mic'd up / studio direct tone; and the DT25 gives you that "mic modelled' signal back, as the XLR out from the DT25. So, that's my reasoning, and where I am going with my rig.
 
That' just me though - but thinking about how hearing your tone and the source of it - a mic on your amp being presented through full range speakers; or an amp with it's guitar voiced speaker and tubes - that's the most important decision / factor which will most properly influence your choice of gear. It's far less logical, it's a matter of the heart, and what moves you to play better and with more soul, with your being in the notes, rather than your head stressing the technical details.

You can achieve exactly what you are trying to do; here is what to do:
 
set up dual inputs paths on the HD500. make input 1 guitar, make input 2 mic.
create a dual amp path, leave the bottom path as "no amp", set the top path as the amp model you want to use to go to your actual amp.
 
make sure ALL fx blocks are moved into the TOP amp channel path - leave NONE in the 'pre' single position before the amp splitter. Same goes for post FX - move ALL post FX into the top amp path.
 
You should now have your signal that would go to the amp in the top amp path, and nothing in the bottom amp path.
 
Go to the mixer settings, and pan them both hard Left and Right.
 
Connect the left 1/4" out from the POD to the FX return of your amp.
Put your HD500 in "combo/poweramp" mode. This will disable the mic modelling.
 
I *don't think* you would need to place a "dummy" 1/4" cable into the right output of the POD, but you *might* need to, so it doesn't do a mono sum of the two channels and cause that feedback.
 
If you prefer, another option would be "Studio Direct", which would include mic modelling; though that won't create an ideal signal for your SM57 mic. So for now, lets stick with the Combo/Poweramp mode.
 
One note to that - not sure how those output modes impact the mic signal, since you are not running it through an amp or processing it. You may want to try both, and see if one sounds any better than the other.
 
Last, go into the mixer section, and increase the level of path B until you get decent levels in your recording software.
 
A note on output modes - if you end up in Studio/Direct, you can get a decent recording ready signal from the path A as well as the mic in path B - but if you are in combo/poweramp, etc - any mode other than studio/direct, don't even bother recording that input path A, it will be configured to sound good through your amp only, and won't translate well to recording.
 
Essentially arm the recording software to a mono track and record of the 1/2 pair, 2 only.
 
Here is a sample patch; I created this offline, so you'd need to tweak the FX and amp model choice, settings to what you want to do with your tone. I boosted that mic input 2 level +6db in the mixer; you may need to adjust that to less or more, depending.
 
Amp+SM57 dual input.zip

You will need to set up a dual-amp, dual-path, panned hard left and right patch. I created a quick "Sample" patch which illustrates this in a basic manner.
 
Input 1= variax
Input 2 = guitar
 
FS1= boost comp / red comp
FS2 = tube drive / screamer
FS3 = '62 spring / hall reverb
FS4 = digital delay / dynamic delay
 
I set the footswitches in a simple way, it's not ideal for actual playing, because each FS turns on/off both channels effect. IE, fs1 will toggle both compressors, fs2 will toggle both drives, fs3 both reverbs, fs4 both delays.
 
You need to, as you will see in the patch (it's in the attached .zip file) drag all the pre and post FX blocks into the two amp channels so as to keep the two inputs divided. The mixer also needs to be panned hard left and right, as it's set in the patch.
 
In this case "path A" is panned left, and that's the Variax,
"path B" is panned right, and that's the Guitar.
 
Keep the output mode as "studio direct".
 
Run the left XLR out to the PA.
Run the right 1/4" out to the FX return on your amplifier.
Dual Tone_Left-Right.zip

The DT25 weighs around the same as one L2t StageSource.
 
"case pack weight" of the DT25 is 50lbs
the L2t specs claim it weighs 39.1 lbs
 
Radatats gave you some pretty good advice, in terms of start with the HD500, see how you like it with your current Atomic amp. The comparison is apt, in terms of the Atomic being full range; so is the StageSource.
 
Personally, I started with an HD500 in 2010, just got a DT25 earlier this year - followed shortly there after with a pair of L2t's. I bought the L2t's to use as monitors, to go with the M20d; I'd eventually like to add a couple of L3t's, and maybe a sub or two. Down the road, so to speak, in terms of budget..
 
That being said, there is something about using a "real" tube amp that the full range gear will never accomplish. However, there is also a simplicity to just letting the HD500 do it's thing, with the full amp modelling, especially when using something like a JTV variax with the acoustic tones.
 
I personally can't make up my mind! I do like the tube amp vibe, and in terms of gigs, that's the direction I am going, the XLR DI out from the DT is solid; and it's mic level, so it will do just fine going into a mic snake and such.
 
I've also run the two L2t's in stereo from my HD500, and they also sound killer. For me, that was more just exploring and having fun - those are definitely used as monitors when jamming with the full band, drummer and such.
 
One thing is for sure; you will need to create patches and banks for each output - the patches for the DT25 *probably* need to be different from the full range / studio direct patches. To get the most from the Bogner side of the DT25, use the "PRE" amp model versions, use the L6Link, and that will configure the HD500 into 'combo/poweramp' mode. Quite similar to plugging the HD500 into the FX return of the DT25. In that case, the HD500 does the FX and the amp model 'preamp' only; the Bogner side of the DT25 does all the tube amps and analog stuff, in reality, rather than in modelling.
 
You will always have a digital preamp with the DT25, even when running your guitar direct into the DT25; it uses the same amp model preamps as loaded on the HD500.

Yeah, it comes with the primary crucial stuff. The USB cord is standard, like the kind you connect a printer to your computer with. You will just need the obvious stuff, 1/4" cable(s) to plug guitar into it, 1/4" to go from HD500 to an amp. Does not have any RCA outs. Has the standard 1/4" headphone jack.
 
It's worth mentioning that when using the HD500 connected to a PC, the HD500 should be designated as the soundcard, if you want to use it for recording. In that case, the audio playback / output is routed out the main 1/4", XLR, and headphone outs on the HD500, so you will need the speakers connected to the POD to hear anything.
 
You will definitely want to deal with the monkey. The Line6 Monkey that is. It's their software which allows you to update the HD500 to the latest and greatest firmware / flashware. Just do what it says, in terms of disconnecting the USB cable when it says, power cycle it when it tells you. Do that first, using the login you have here to connect and register your gear with L6.
 
When it prompts you if you want to save your patches during update, say 'no' for these first updates.
 
Once you have everything updated on the HD500, Monkey should also install drivers on the PC, and the HD Edit software. Do yourself a favor, and get ALL of that out of the way first. While drinking those beers! ;)
 
For me, I like to start in studio/direct mode. Especially if you intend to connect to a PA. Once you get a DT amp, that changes everything, but for now, studio/direct is essential. It's your new best friend.
 
If you have any amps, use the FX return. 1/4" cable from HD500 (L) (mono) out to the 1/4" FX return on the amp. In studio/direct mode... This will sound most correct for the time being.
 
Now, no offense intended to the onboard presets - but skip them, all of them. Head straight to a blank patch. Choose an amp model. Play. Choose a different amp model. Play.. Repeat, adding beer as needed.
 
When you are feeling adventurous, head over to CustomTone and snag some patches. Load them into HD Edit, using the 'send' function will transfer them to blank slots on the HD500. I suppose same goes for the onboard default presets.
 
The reason I say 'start with the blank patch', is there are some SERIOUS volume differences between patch to patch. Like, scary big volume jumps. Auditioning a few of the HD amp models will give you a good sense of what this thing has to offer. Also tweak the mic choices; any given amp model will sound radically different based on the mic choice. Again, because it's studio/direct, this is the setting which will sound 'right' for direct recording, direct to PA, and to any FX return of an amp - because you want to bypass external preamping and tap the HD500 tone direct to a power amp with as little coloring as possible.
 
The reason I say use the HD edit software, is because it makes it a good bit more obvious when you look through existing presets, and when you want to set up your own.