Topic: CM2606 based DAC - on linux

[sc_r]

Hi DrLava

- just ordered a full kit from the URL - hoping it's one with the DC/DC converter?

*jumps around room waiting for deliveration*



- this is the USB card I have



and this is the card so far - have soldered on connections to 25-pin connector from and old SCSI cable.

Nice

[James]

This has a 8768 chip but looks like a small board - what do you reckon?

http://cgi.ebay.co.uk/Asonic-8-Channel-Soundcard-C-media-8768-Chipset-3D-PCI_W0QQitemZ200373499133QQcmdZViewItemQQptZUK_Computing_ComputerComponents_SoundCards?hash=item2ea730f4fd&_trksid=p3286.c0.m14

This PCI card is Perfect! You should not have any problems with this one.

WRT the correction amp and the board you have pictured above, it won't work right with the parts values that come with the kit. The problem is that this board has a lower DC offset voltage than any other I've ever seen. Most sound cards run on +5VDC. That puts the DC offset at a bit below half of that at around +2.25VDC. This board runs on +3.3VDC and has a DC offset of about +1.2VDC. There just isn't enough adjustment range in the offset trim pots to get to zero volts!

The solution that I can up with is to use a variable negative voltage regulator. The kit you ordered has a fixed -5VDC regulator. It should be fairly easy to figure out how to work a variable negative voltage regulator and another trim pot (to set the voltage) into that kit somehow.

http://www.national.com/mpf/LM/LM337.html

James. 

[drlava]

with the values I included in the kit it should be fine

[sc_r]

OK cool thanks for info.. am going to continue to play with LaserBoy software until I get my new PCI card through:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260462436715

different to the one above but James you mentioned that you have had success with VIA chips before?

Looking forward to getting the correction PCB pack and building.. I wander which will arrve first!

[James]

I would say yes to this card, but I can't be sure. It's a 1723 ?

The way I found a good card for Linux was to download the latest kernel and look in the configuration tool for the sound chips that have drivers!

I have not compiled a kernel for a while! 

James. 

[drlava]

I heard from a birdie that a linux driver for the cm* usb has been written in linux for laser show use...  not sure how long before it comes out but it's an exciting bit of news.

[James]

Do you know what the reason or motivation was for this driver development?

Just curious....

I mean, come one!

Who in their right mind would create laser software for Linux? 

James. 

[sc_r]

Woohoo! The correction board arrived today.

YUSSSSSSssss

DrLava - is it right that I should only have 50k pots and no 10k ones? (they say W503   036T) on them.

...starts to build

**EDIT** - so I just read your instructions.. got it.

blimey those surface caps look hard to solder..

[drlava]

they are easier than you think.  Just wet the solder pads with solder, hold the cap with a tweezer and touch the iron to the pad and cap and the solder will melt together.  Leaded solder is easiest to work with.

[James]

Surface caps?

What have you done to that little kit?

James. 

[James]

Hey man!

Give us an update!

We want more pictures! 

James.