What exactly is the "correction amp" for??

[drlava]

yes, that's the ground of the sound card, and no it wouldn't cause this.

Have you looked at the pinout of the dual op amps? The pins are labeled - in, + in and out for both sides. Just connect them the same way as in the diagram.

Oh, and try this: disconnect the post amp and try to use the sound card as a sound card. play a 44.1kHz 16 bit stereo wav ripped from a high quality CD with high frequencies in it. Compare how the highs sound to how they sound from your reference CD player and the 'normal' windows sound card using some good headphones.

[Things]

Going by this diagram http://www.xs4all.nl/~ganswijk/chipdir/pinusr/tl072.txt

is that right? I'm starting to build the blanking circuiit now, so stuff is clearer, but I am still stuck as to why its going distorted.

EDIT: Finished the blanking circuit, but something is wrong. It's just pulsing the green laser, it is very low power, and its not even close to where its supposed to be blanking. Any idea's?

EDITEDIT: the blanking prob is in my circuit, fixing it up now.

[Things]

Okay, got some pics.

Just to clarify, there is NO BLANKING in these pictures!

lasertennis ~7K



The 0's appear normal, and get better alittle below this speed, but its arder to capture.

lasertennis ~20K



Notice how the 0's have shrunk and got distorted?? That is the problem I am having ...

LaserBoy circle WAV - Not sure on speed, but whatever laserboy is set to at default.



Doesnt look too much like a circle, does it?

Laseroids - ~7K



Not the best pic, but you can compare it to this one:

Laseroids ~20K



The letters are more distorted, some lines overlap, some letters wayyy to rounded.

LaserBoy xmas tree - Unsure



Notice how its not totally a triangle + the star ontop is messed up

LaserBoy Gear - Unknown



Cogs are distorted BAD!

LaserBoy bear - Unsure



Also quite distorted.

LaserBoy Logo - Unsure



Not the best pic but this one is VERY distorted!!

EDIT: some more:

ILDA test pattern, through spaghetti, at 20K:



THis seems very distorted.

"Yom" @ 20K



"Disc" @ 20K



THis is one of the ones that actually show up OK!

Another laserboy frame @ 20K - THis is supposed to be that square, with the even lines running across it.



This one is absolutely horrible!

Hope those help

[carmangary]

Looks to me like you are just trying to use too large of a scanning angle or scanning too fast.

[Things]

Hmm, the max I tried scanning at is 20K, and since these are 20K galvo;s, they should be able to do that, atleast. so manybe its a combination of bad tuning + too large a scan angle.

[thesk8nmidget]

it possible that these were tuned lower than 20.

my DT40's are tuned for 30,000

[carmangary]

What is your scan angle with these images? I don't recall you saying? If it is maxed out then it makes sense that they look distorted. If it is around 8 degrees or less then maybe they should look better. The circle in your ilda test pattern looks oval which indicates to me that you need to do some tuning.

Can you display some pics from your DMX board? I am curious to see what they look like since there won't be any distortion coming from them.

[Things]

Everything on the DMX board scans fine. Though the scan angle from the DMX board, is larger than this. Not exactly sure as to the exact scan angle, but i'd say aound 15 degree;s maybe? they are factory calibrated at 20 degree;s, and have a max of 30 degree;s, I dunno how i'd be overloading them.

[drlava]

The DMX board might be driving them slower than 20k. Can you post a pic of your galvos and the galvo amp?

[carmangary]

Everything on the DMX board scans fine. Though the scan angle from the DMX board, is larger than this. Not exactly sure as to the exact scan angle, but i'd say aound 15 degree;s maybe? they are factory calibrated at 20 degree;s, and have a max of 30 degree;s, I dunno how i'd be overloading them.

All galvos I have received that were supposedly tuned from the factory were actually not tuned well at all. There are many posts on here that also back up that statement. So, it may not be good to assume that your scanners are tuned well. It could be that your DMX patterns are so simple that they display OK but when you try to display more complex ones you have problems. Unfortunately, you have a lot of unknowns because you don't know how fast the DMX board is scanning. You don't know for sure that your sound card DAC doesn't have some distortion coming out of it. You aren't sure that you don't have a wiring issue. Is there anyone on here that lives near you that could help you out by hooking up your sound card to an oscope or maybe let you hook your scanner to a different DAC that is known to be working correctly? Perhaps you could send your galvos to Bill Brenner at Pangolin for him to tune them up nicely for you. At least then you could 100% rule out some sort of tuning issue.

I used to be all for the idea of using a sound card as a DAC but after building one and actually using it I am not as much for it. Once I got it all set up correctly it worked fine but it took me a couple of days of watching scope signals and fiddling with my Windows and sound card settings before I got it working like it should. I am not recommending that you abandon your soundcard DAC because I am sure you will eventually get your issues sorted out... I'm just kind of thinking outloud for others that might want to try using a soundcard. Maybe for the novice the frustration isn't worth the savings.

But again, assuming your wiring is OK and you have your sound card set up OK, I would next display the test pattern at 20K 8 degrees and try to see if fiddling with the tuning improves the images. As long as you don't go crazy with the potentiometers and have an understanding of what you are doing you should be fine doing that. If the images don't respond the way you expect when you adjust the pots then just stop what you are doing.

Anyway, that's about all the advice I have left. I hope you get past this soon so you can start having some fun.