Experience with this DIY DAC ?

[Segran]

As pin 20 is a logic input (when CS8416 is in hardware mode) it does't really matter if it's wired to +5 or +3.3V via a 47k pull-up resistor. Logical high level is specified at 1.0V for the chip, low level is 0.5V.

It doesn't make any difference what so ever if you connect it to the regulator or to for instance pin 21 on the CS8416 chip (Logic Power). It is a pure digital signal so if the power on pin 21 is clean enough to work as Logic Power, it definetly is good enough to pull up a logical signal! So don't go out on a wild goose chase on this subject!

I have modified the LPF using the component values given by Crystal and I get the same clear high frequencies as without the filter caps, but with a very good filtering of frequencies above the audio band. This is the way to go, removing the filter completely may cause "undesirable side effects" if it's connected to an amplifier with a good power bandwidth. Frying your tweeters may be the only way to dicovere such an "undesirable side effect.."

Removing all 1nF caps and leaving only C32 in place you will have a rather "soft" filter with it's -3DB point att 150kHz and only -5dB at 1MHz.

[Segran]

Have anyone tried the DIR 9001 replacement for CS8416 that is currently offered by Mr. Chan?

192kHz will obvioulsy not work anymore, but I'm not using that (for the moment at least) anyway.

[Mush]

Forgive me for being so simple minded. I understand lots more about tubes than DACs. Could someone please post a close up of what is done to the CS8416 so I can understand what it should look like when I'm done?

Thank you all for your excellent posts. I am learning a lot and that's great stuff.

Best wishes to you all.

Ciao -- Mint

[johnm]

Can anyone recommend a good freeware drawing package for the PC? I'd like to draw a simple visual representation of the op-amp/filter areas to make it easy for people to upgrade their boards with the proper Cirrus Logic component values.

Many thanks,

- John

[Mush]

Hi John,
A drawing of the mods would be great.
I've used Inkscape in the past. It's simple and free.
I hope it works for you.
http://www.inkscape.org/
Thanks very much.
Ciao -- Mint

[johnm]

Thanks Mint - I'll have a look into that

[Mush]

Hi John,
I forgot to include a youtube link that has a lot of tutorials that I found.
http://www.youtube.com/user/heathenxyt

Ciao -- Mint

[Kevin Wood]

I've not had time to play with this recently but I plan to go through the rest of the mods on my DAC and I'll take pictures along the way.

Kevin

[johnm]

Ahh super will be even better to see photos, and perhaps over-lay the part no.s over each component?

I'm stuck at home suffering from M.E. so haven't gotten around to finishing my very crude layout using that software package yet. Your photos sound like a much better idea.

[johnm]

Has anyone had any luck implementing the recommended filter values? I have the resistors on order and already have the caps so am looking forward to trying this out for myself. Just hope the parts are easy to desolder.

The DAC still sounds good - subjectively - to me as it stands however, with perhaps an ever so slightly lightweight midrange?

- John