if you use the max.wav file I posted in the "First scanner" thread here, you can tune the sound card with a DMM.
Elektro, if you can't stand arrogant children, then LPF obviously isn't the place to be, considering atleast 50% of it's members are <20. Like I said, I don't care about age. I have done it before, and I have found errors and problems, and I have just as many rights to express my opinion as you. I said TTL sucks, yes, but who cares? You use it, you don't have to get all upset because someone says so. That's my opinion, and I feel analog is a huge step up from TTL even in a single colour setup. People who get all emotional over an online forum worry me, but whatever, I am also done arguing this.
The difference between the FB3 and the soundcard DAC is, well, the price, and also the FB3 comes ready to go. only thing to DIY if anything is an enclosure.
The quality is also higher, as it was designed to be a laser show DAC, a sound card isn't. The software is top notch, no crashes at all.
Sorry about your thread XysteR, but I will still be here to help if needed.
Tuning the SDC is as easy as this:
Connect it to your computer, make sure it's properly installed and set on 6 or 8 channels in it's config, and also your default sound device.
Don't use the card, but connect your DMM/o'scope to output 1 and a G on the correction amp. Adjust the offset pot untill it's at 0V, then move onto channel 2 and do the same thing (You can just use the same ground each time).
Then go back to channel 1, and play this file
http://files.getdropbox.com/u/203420/max.zip in any media player AS LONG is it supports multi-channel output (most do).
Adjust the gain pot on channel 1 untill it drops to 5V, then do channel 2 etc.
Then your done, maybe put a little blob of glue on the pots so they don't move accidentally.
EDIT: If your worried about blowing the diode, underpower the diode by a few milliamps or adjust the DAC to output like 4.8V max, which should still give you pretty much full output.