USB Audio DAC mod + LaserBoy Correction Amp

[James Lehman]

Here are some nice pictures of a hand made LaserBoy Correction Amp and one of those famouse USB sound cards.

GRIBYX = green, red, intensity, blue, Y, X !

Cable shield is grounded.

The twin lead is USB +5VDC and GND (white stripe).

In order to get the right levels out of this audio DAC, you need to display the provided software effects / mixer application and set it to 6 channels. Then you need to set the level of each channel. This goofy thing has a built in digital gain with automatic digital limiting (YUK! ). It has NO EFFECT if you set the levels to just high enough but not too high!





See the long, plain black box? That is a DC/DC converter that takes +5VDC and provides +/-9VDC for the op-amps. How cool is that?

BTW, the printed boards are done and a bunch of parts are on their way! We will have 25 kits available very soon. More after that! Those DC/DC buggers are made when ordered!

James.

[buffo]

Excellent! I've got the same sound card sitting on a shelf, just waiting to be modded. Looking forward to being able to run Laserboy on a real DAC. (Also looking forward to trying out Dr. Lava's sound card driver that emulates the Easylase USB DAC. Hoping to be able to play some of Zoof's creations on it!)

Let me know when the printed balance boards will be available!

Adam

[allthatwhichis]

Hey, will Dr. Lava's driver et someone use LDS on a sound card DAC?

[buffo]

That's my understanding, Aaron. I'm hoping to be able to use it with Mamba Black myself. (Yeah, I know that Mamba Black has a driver for the QM-2000. I've actually run it that way, but I prefer to run Showtime with the QM-2000...)

Adam

[allthatwhichis]

(Yeah, I know that Mamba Black has a driver for the QM-2000. I've actually run it that way, but I prefer to run Showtime with the QM-2000...)

Adam

Amen to that. I'd like to find a "cheap" way to be able to run both, ST and LDS, on separate scanners of course...

[James Lehman]

This amp should work with just about any USB or PCI, Dolby 5.1 or 7.1 surround sound card. I have not tried one yet that didn't work!

You might have to look a bit farther than the obvious output decoupling caps on some boards.

In the good old days, I just looked in the Linux kernel to see what DAC chips were supported by Linux drivers and got cards with those chips.

The card you see on my website is one I got of a shipment of three that cost a total of $21 sent to my door. It's a C-Media 8738 chip.

Something to note about The LaserBoy Correction Amp: It is an inverter! So if your DAC is NOT an inverter you will end up with an inverted signal! That means that you need to send inverted wave to the DAC so that it can pass it to the LaserBoy amp to be inverted again. Does that make any sense at all? Some audio DACs are inverters, so you send positive (non-inverted) information to the DAC.

James.

[drlava]

Something to note about The LaserBoy Correction Amp: It is an inverter! So if your DAC is NOT an inverter you will end up with an inverted signal! That means that you need to send inverted wave to the DAC so that it can pass it to the LaserBoy amp to be inverted again. Does that make any sense at all? Some audio DACs are inverters, so you send positive (non-inverted) information to the DAC.

James.

That's OK since both the driver and your wav writer routines have options for inverting the data.

[James Lehman]

Excellent! Pretty soon, everyone will be thinking in waves!

James.

[barold]

im back!

anyways, i have a lot of catching up to do, but i saw this and I am very excited!

I've been meaning to clean up my external electronics, and a printed board would be quite spiffy. I also told some one I would build them one, but this would be a lot easier!

Cool James! Will you be selling the kits with parts and the printed board? Any ideas at what the cost is going to be?

Barold

[James Lehman]

DrLava and I put it together. He's got the boards and I just ordered a bunch of parts. We don't have printed instructions yet, but you already know everything you need to know!

James.