DAC to AMP to Driver?

[drezglis]

Ok I am attempting to build my own USB DAC with correction AMP I think Ill be getting a 20 Kpp galvo set. Now Ive got the fact the the software goes to the USB card and that goes to the AMP which then goes to the galvo without a show card since the DAC is the show card. Now I want to build my own laser with driver for each color. But how do I wire up to the laser? Can anyone point me in the right direction? I see that each laser pin on the AMP will have a (#), and a (G),

[swamidog]

Ok I am attempting to build my own USB DAC with correction AMP I think Ill be getting a 20 Kpp galvo set. Now Ive got the fact the the software goes to the USB card and that goes to the AMP which then goes to the galvo without a show card since the DAC is the show card. Now I want to build my own laser with driver for each color. But how do I wire up to the laser? Can anyone point me in the right direction? I see that each laser pin on the AMP will have a (#), and a (G),

pangolin has an excellent guide for this:

http://www.pangolin.com/resguide12.htm

[james]

Ok I am attempting to build my own USB DAC with correction AMP I think Ill be getting a 20 Kpp galvo set. Now Ive got the fact the the software goes to the USB card and that goes to the AMP which then goes to the galvo without a show card since the DAC is the show card. Now I want to build my own laser with driver for each color. But how do I wire up to the laser? Can anyone point me in the right direction? I see that each laser pin on the AMP will have a (#), and a (G),

Am I correct in assuming you plan to build a modified sound card, aka LaserBoy DAC?

I can help you with that!

I know about as much about that as anyone!

James.

[drezglis]

Yes....it is....wow the creator of LaserBoy! So you defiantly have the skills and knowledge! .... with this DAC sound card/ drlava correction AMP I have a 20kpp galvo coming and I wanted to build my lasers. I see why a D-25 plug set up would make sense. But only a few pins actually get wired up right? Now from this if pins are configured correctly I would correctly wire to the galvos and the lasers. But on the topic of lasers do I use the output of the correction amp lets say for the blue laser to the modulation on a TTL driver? Does the driver have to be TTL in order to modulate and control the diode ( cause isn't this just basically on/off by 0V off 5V on)? Yes please help me out on this one...I have been scooping through various forums and web pages to develop a working idea. Like on the correction AMP it was only a few pins now which pins on AMP go to which pins on DB-25 and from a DB-25 which pins go where? The galvo set up does not have a show card. It seems the two galvos have two driver boards. And on those boards there are two - 3pin plugs and a few other plugs going to the galvos and power supply. So is this where the control off the AMP to each galvo is suppose to interface?

And another thing I saw they said something about analog modulation giving better blending of the colors is this possible by the type of drive I decided to use per diode (which is dependent on the operating specifications of each diode) or is this not possible?e
Also if I wanted to do Blue or Violet, Red, and Green what mW range should I be working in for each color?

Also do you know if the bare board and the assembled AMP are still up for grabs on http://hacylon.case.edu/ebay/laser_d...ection_Amp.php

I would love to assemble it myself but it would be cheaper to go the already assembled route. Unless you know a website where I can get those parts for less. The main parts that seem to drive up the price is the 12 x 50k potentiometers

[james]

WOW! That's a lot of questions!

First thing you should understand is that a modified sound card DAC is single-ended! That means it is not differential. There is one and only one ground and all of the signals are single phase and relative to the same ground.

This is not typical of some laser show controllers.

You will notice that your scanner amp inputs are three wires. That is differential. There is a ground and a non-inverting input and an inverting input. This is much like an XLR pro audio (balanced) connection: one ground and two signals that are 180 degrees out of phase.

You should wire up your laser projector to be able to take balanced signal inputs and you should wire up your sound card DAC to be grounded on all the negative phase signal lines.

I know this is confusing, but we can sort it out in further conversation.

You need to make sure that the TTL inputs on your lasers behave the way you describe. Have you tried applying +5V on the modulation input to see what happens?

If you have only TTL modulation then you can only expect to get 7 different colors from your projector: red, green, blue, yellow (r+g), cyan (g+b), magenta (r+b) and white (r+g+b). If you had analog modulation on all three colors, you could mix thousands of colors.

So lets deal with this in two separate parts: First lets wire up the DB25 for the projector for differential input and then we'll wire up the DB25 for the DAC for single-ended. The two work together very nicely.

http://laserboy.org/forum/index.php?...sg1411#msg1411

James.

[drezglis]

So on the DAC DB25 wiring you said this SC DAC is single ended. And that there is only one shared ground so on the second diagram for wiring DB25 for the DAC as single-ended each ground is actually coming off the same source? Now isnt the DAC actually inverted? Heading out to the scanner If pin 1 is X and pin 14 is X (gnd) But is the modified sound card DAC only in inverted signals? How am I to wire the scanner to take balanced signals if the DAC is signal ended?
So off the card its going to be single ended.
Because the sound card DAC is single ended Ill follow the 2nd diagram for wiring up a DB25 connection? And because the scanner is set up for deferential I need to wire up a DB25 as in diagram 1. If the scanner is only taking the inverted phase signal off the correction AMP and I need to ground the unused non-inverted signal how do I do that? (central grounding point? isolated to prevent ghosting? <-whats a good source?)
And how would I wire up the sound card DAC to be grounded on all the negative phase signal lines? Since I'm using the inverted signals and I need to ground the unused non-inverted signals on the scanner will I apply the same technique here as well?

Would pin 25 work for grounding unused non-inverting input on the scanner? Or do I just ground that to a isolated source like a metal object free from connection to AC ground.
The manual for the scanner sugests ground free operation between computer and drivers.

[james]

Yes. The correction amp is an inverter. The solution to this is to invert the data being sent to the DAC. Any application that knows how to communicate to a sound card DAC can do that.

You should wire your projector (scanners) as differential. If you wire the sound card DAC to be single ended, the negative phase of the scanner inputs get grounded as soon as you join the DAC to the projector. That is exactly what you want!

The DB25 on the output of the sound card DAC will have every pin in the bottom row (14 through 25), except for 17, all tied together and to ground. There should be a wire connecting pin 17 to pin 4. This acts like a switch to indicate to the projector that the DAC is plugged into it.

What sound card are you using?

What laser control software are you planing to use with this DAC?

[drezglis]

I contacted Andrew about the Laser Boy DAC he said, due to safety and consistency issues with those sound card DACs, I've moved on the the open source OLSD DAC, RIYA, and EtherDream DACs. Which one should I get and how does this change what Im working on? I wanted to use Laser Boy, LFI laser player, HE Laserscan, and what ever else is the most flexible and user friendly. He said to contact you for one. I haven't bought the USB sound card or the correction DAC yet I was going to try and get this one-
C-Media CM106 USB 2.0 External Sound Card Box with 7.1-Speaker SPDIF Optical Output. Which ones do you have and what are the advantages and disadvantages as well as the costs?

[swamidog]

i use LSX and an etherdream DAC. i wouldn't say LSX is the most user friendly laser show app, but i would say it's the most powerful and flexible in its price class. there are some awesome video tutorials on using it here:

https://www.youtube.com/watch?v=POrAv7M8qEg

and here are some laser shows i've made with it:

https://www.youtube.com/watch?v=uVSs...eature=mh_lolz

you can get package deals here: http://www.ebay.com/itm/LSX-EtherDre...item2ec09bd51e

I contacted Andrew about the Laser Boy DAC he said, due to safety and consistency issues with those sound card DACs, I've moved on the the open source OLSD DAC, RIYA, and EtherDream DACs. Which one should I get and how does this change what Im working on? I wanted to use Laser Boy, LFI laser player, HE Laserscan, and what ever else is the most flexible and user friendly. He said to contact you for one. I haven't bought the USB sound card or the correction DAC yet I was going to try and get this one-
C-Media CM106 USB 2.0 External Sound Card Box with 7.1-Speaker SPDIF Optical Output. Which ones do you have and what are the advantages and disadvantages as well as the costs?

[drezglis]

That's a way out of my price range what about the audiolase kit do you know where I can get one of those? Or any other type of correction amp kit or board? I would even wire up the DrLava myself in a peg board if I had a better view of the schematics. I really wanted to get into this from the creative artist/technical aspect. My funds are very limited so I'm trying to stretch what I can...

I saw this pic I would use this but I can't figure out the exact wiring...
http://www.photonlexicon.com/forums/...Correction-Amp

By the way those are some fresh laser graphics wayyyy cooool!