USB Audio DAC mod + LaserBoy Correction Amp

[James Lehman]

i was using VLC.. you know that.. i was sending a white circle wave created in laserboy to the soundcard using VLC media player in 6 channel mode .. worked great

I was just asking kind-of in general, because there are now a couple of ways to send data to the sound card DAC.

I'm not sure of all of the details, but it seems like Windows Media Player might put an altered output volume into the mix. I'm not sure if any of the other wave player do that.

James.

[keeperx]

well i am worried that spaghetti and VLC may be different. i better look into this, because i tuned the 5v in VLC

[James Lehman]

well i am worried that spaghetti and VLC may be different. i better look into this, because i tuned the 5v in VLC

The good news is that Spaghetti + a sound card is the work of two PL members, so any problems with that can be fixed.

James.

[carmangary]

well i am worried that spaghetti and VLC may be different. i better look into this, because i tuned the 5v in VLC

Spaghetti doesn't create waveforms. It only sends the frame information to DrLava's EZAud driver. Spaghetti does use the full range of 16 bit values (-32768 to +32767) for X&Y, though. So, as long as EzAud is doing its thing you should get full deflection. You won't get 100% output for colors, though. Since I have to convert from 8 bits to 15 bits I shift left 7 and the max is slightly low (32640). So, 4.98V. Close enough.

[buffo]

wow, was that done with the scanpro 20's??

Sorry for the late reply, Things... Busy as hell lately.

Yeah, those were the review pictures for the ScanPro20's that I reviewed this summer. They were given away as one of the door prizes at SELEM 2008.

When they arrived, they were not tuned that well. I had to tweak them a bit to get it looking that well. But they *will* perform amazingly well.

Sounds like you've isolated your problem to a faulty scanner, and that's good that you found it. However, keep in mind that there could also be issues with the sound card DAC. (Or, more specifically, the settings on the correction amp.) The one I have was working *flawlessly* at SELEM, but when I plugged it into my machine at home it was clipping baddly. I was able to tweak it back in line to some degree, but it's something you need to be aware of. If you *think* the DAC is dialed in perfectly when it's really not, you will never be able to tune your scanners. (It will completely hose up your scanner tuning...)

Adam

[James Lehman]

Spaghetti doesn't create waveforms. It only sends the frame information to DrLava's EZAud driver. Spaghetti does use the full range of 16 values (-32768 to +32767) for X&Y, though. So, as long as EzAud is doing its thing you should get full deflection. You won't get 100% output for colors, though. Since I have to convert from 8 bits to 15 bits I shift left 7 and the max is slightly low (32640). So, 4.98V. Close enough.

If you tune your gain pots to +5VDC, using the white circle in the form of a LaserBoy wave, you should be perfectly set up for Spaghetti.

LaserBoy does exactly the same thing. It promotes an unsigned 8 bit value to a signed 16 bit value by shifting up 7 bits.

James.

[Things]

My ILDA pattern, at best, comes out like Sean's. But, since I have exactly the same problem as him, and originally I thought my X was running faster than my Y, I think it may have traced back to a faulty galvo :/

Dave would be starting to get annoyed with me and so many PM's

[seanharrison]

My ILDA pattern, at best, comes out like Sean's. But, since I have exactly the same problem as him, and originally I thought my X was running faster than my Y, I think it may have traced back to a faulty galvo :/

Dave would be starting to get annoyed with me and so many PM's

Have you not spoken to dave about replacing your scanners ?

[Things]

He said he could replace them for me, but I really dont wanna have to send them back to china. No idea what shipping would be like

[James Lehman]

I took a board that I had made with me to meet drlava in Cleveland. I could not get the 6th channel to do anything! I checked it every way I knew how.

He found this!




If you get one of these, look closely and scrape off that copper!

James.