try using software based noise reduction then, make sure to record a few seconds of just that noise before and after each track (the noise reduction i use requires this to sample it and accurately remove it from the rest of the audio)

Maybe you're right on pro sound and mixer, I don't know.
What I try to say, I have try many DMG on my mixer with standard stuidio stuff : MPC, electribe and drumstation.
There is allways a pshiiiiii or brrrrrrrr, some kind of noise which is not my tasteat all.
I don't have any noise gate in my audio stuff.

SP does not seem to have this issue of brrrrrr, pshiiii.
Pro sound DMG seem to have less issue on this mixer, maybe the pro sound increase the sound enough and my mixer does not amp too much noise...
I may be wrong, it's what I feel listening to my mixer.

I've got a zero 8 mixer which are known to be bad amp and a little noisy.

incorrect..
pretty much all a prosound mod does is increase your signal to noise ratio...never really necessary (unless maybe you're also using other instruments that have very high output levels, i always used one with my electribe esx-1 since that thing was loud as hell)...you can always do noise reduction in post-production or use a hardware noise gate of any sort (i have a behringer autocomp pro xl that i keep around for this reason)

I like myself some of the good old DMG, but as everyone said you shouldn't worry.

Using the DMG is not about being 1337, but it's really cheap, reliable and powerful.
The GBC is really useful too, but don't worry about the Gameboy Light, it sucks.

I use mainly gba sp with ems card for lsdj, nanoloop 1&2.

lSDJ on GBA SP is not really useable with a gba linker IMHO.
I have 5 to 10 dmg and for me DMG are cool if they are moded, they look great like an old car.
They don't have better sound than SP they have different sound.
DMG need to have pro sound if you like to use with mixer.
SP don't need prosound mod.

They don't sound exactly the same and I like that, there is no "better" sound.
Some GB make some pshiiiiii sound and they are not useable easilly with headphone or mixer.

Both SP and DMG are the best model IMO.
They both sound good, but for me DMG need backit and pro sound.
Choose your weapon.

I had an SP but didn't like the sound when recording.  Tried to use it for just writing but if the battery died while I was away from a charger, then I was out of luck.  My current equipment is a GB Pocket for writing (unmodded) because it's very mobile and a DMG for recording (prosound now).  I didn't use prosound while recording for a long time but I gave it a try and I personally think there is a sound difference.  But like others have said, try out different units and see what you like best.

There's a very simple mod for the GBC now where you add a resistor and it pretty much kills the background noise. Another one adds bass (though this isn't necessary as every mixer has EQ). Prosound it for good measure and congratulations, you have the best sounding and fastest Game Boy out there. Front light it for optimum usage, and upgrade your LSDJ cart to the latest version to cut down on sample noise during playback.

I will say though, that since I'm not really playing much chipthrash stuff anymore, I've kinda switched back to using DMGs live when I can (I do not actually own one anymore so I have to borrow). Especially in a live situation, the sound difference isn't that noticeable. I just prefer the size of the DMG over the GBC. I guess size does matter.

My advice is to actually try them and see how they fit your own needs. If you're willing to dig you can get all of the above for stupidly cheap (I once bought a bag of 12 for £12) and have an array of them to try out. You could even borrow one.
If you want to use a different gameboy because you think everyone else uses a DMG to feel "leet". You're just trying to find the same supposed sense of superiority by being different.

Don't worry about other people, find what works for you.

My tuppence (your mileage may vary):

• DMG's sound pretty good unmodded actually. Pro sound is mostly just to stop it sounding like shit if you're running it through a lot of cables at a club or whatever. Classic sound, chunky and bassy.

• Color's have a better CPU but can be really noisy unmodded. Modded they're actually pretty similar to the DMG.

• Advance's used to be hated on because the wav channel sounded bad. As Nitro pointed out, he just fixed that. Generally speaking though, I've found them a bit raspy and noisy. The SP is basically the perfect handheld though, and the back light is sweet.

I mostly write on a color and then record and do everything else on a brick.

hmmm. well until recently i used only stock dmg's for years, i have a fancy modded one now( justinthursday did it, i know nothing about modding) but really much of my choice is purely aesthetic. it seems any argument for other models having disadvantages have all been overcome with some type of mod or adjustment so at the end of the day i just think my brick looks sexier and feels more comfortable. now i have hit obstacles where a 200+ bpm track im trying to write runs perfectly on a color but needs to be scaled back for a dmg cause it just cant process it, but unless your on some kind of speedcore/chipthrash kick i dont think this affects too many people.

from my experience,  sps vary on signal to noise ratio.. if the you have doesnt produce too much of a hiss in the audio output, id just stick with it for a while

I've read that gba produces aliased waveforms, through I can't confirm it. Anyway the truth is that it's probably not important. Even if you had an unmodded gbc you would adapt to the crappiness of it and make some cool sounds.

It really about sound preference, i enjoy the dmg with pro sound, i wouldn't use an sp with out an head phone jack.

But i doubt you would be disappointed in the "modability" of a dmg, and plus, it makes you look cool on stage.

AGS - 001
AGS - 101 .__doesn't dim, gets brighter...never really compared the sounds.....to be continued >.<

The different types of GBA have traditionally gotten a bad rap because wave playback kind of sucked. However, now there's a fix for that makes it sounds not completely terrible. (Thanks self for discovering this!)

I know this wasn't in the question, but avoid the original GBA. The button layout sucks for LSDj and there are no good and widely available options for backlighting it.  (actually frontlighting, technically speaking.)

There are two models of GBA SP, and one has less background noise than the other. Other people will know more about that. And as mentioned above, GBA SP is a small neat device, though original GB cartridges will stick out a fair bit, which takes away some of the neatness, if you want to carry it in your pocket, say.

The Sp does have more noise. I couldn't find a good audio comparison with the DMG, but kitsch has a pretty good example here http://store.kitsch-bent.com/product/pissbox

Scroll down and compare the audio of the CGB and GBA SP. Also for a better run down see Another Castle's post above, it has every GB with audio