EzAudDac Alpha release: Cheap DACing!

[thesk8nmidget]

ahhh i see it now.. thanks! that made it pretty clear!

[thesk8nmidget]

woot woot it works! thanks for the info on this!

i got it all to work!

[Things]

Hey, i have all the components to build the correction amp, but I only bought 2 op-amps, knowing they were dual. How exactly how do you use them in the dual configuration? I only have to run X, Y and G.

Thanks

[Things]

OK, let me clarify the circit abit before I start building it.

So, all the 0V grounds go to the ground on the sound card?

On the circuit, after the 1K resistor, it says 2-5v. Does that mean, I can just give it 5V from the sound card, there, and just leave the 1K resistor, and everything behind it out?

Also, on pins 4 and 8 of the op-amp, it has Vcc and Vdd, where do they go?

Can this whole circuit run on the 5V from the sound card? (I have a little circuit here that can take a few volts, and step it up if needed, but i'd prefer if I didnt have to)

Like this?



thanks

[James Lehman]

If all you have is the 0 to +5VDC from the USB cable, then you need a neat little thing called a DC/DC converter. That is part of the LaserBoy Correction Amp kit. It takes 0 to +5VDC in and gives you +/-9VDC out so you can power your op-amps with +9V on the +V input pin and -9V on the -V in pin. GND floats between these two voltages.

If you stay with it and keep asking questions, you'll get it.

Ordering a kit would be a good idea.

James.

[Things]

hey James, paypal isnt working for me, so I have all the components to make it. I'm just windering where you give the circuit the 9V?

As I said, I do have a little DC/DC converter, but the circuit calls for 2 15V supplies, which threw me off.


EDIT: I have found that the 2 15V supplies are so that the circuit gets a + AND - supply. Would removing the 1K resistor, and just giving it 2 USB inputs do the same thing, or do I need something with a + and - output?

[Things]

On that circuit, it wants a +/-15V supply, which I am giving it, with the galvo PSU. Now, my problem is I am getting like 12V on the output!!!

that 1K resistor is supposed to limit it to like 5V is it not? I get around 19V between that and the + supply.

does that mean: 15+15=30V ??


EDIT: Well, the driver is working now, but the image is still VERY distorted :/

[drlava]

Hey things, why didn't you buy a kit it would have made things a lot easier for you, especially if you are just learning to read schematics. The place in the schem. where you say 'can I just give it 5V here' that place should be -5V. The 1k doesn't limit it to -5V, the zener diode attached to it does. 15V+15V=30V, yes. That is the voltage across the op-amp supply if you power it from the galvo regulated circuit. It works fine, that's the way I had it for a while, too.

[carmangary]

FYI - I just received a couple 5v to +-12V DC-DC converters in the mail. I am going to try them to see if I can get full +-10V out of the correction amp so that I get the full scan angle. I'll post my results later.

[Things]

I have the amp's working, I can adjust offset and all, but the distortion is still there, but anyway I have a new thread for it, so i'll discuss it over there and leave this place clear.