Soekris Dam Dac

[Dan155]

Hi Nige,
what caps are you planning to use? I'm also curious what the reference buffer opamps are ... can you tell? Also, can you see how the reference filtering is being done? Would definitely want a film cap there rather than ceramic.
Dan

[nige2000]

Hi Nige,
what caps are you planning to use? I'm also curious what the reference buffer opamps are ... can you tell? Also, can you see how the reference filtering is being done? Would definitely want a film cap there rather than ceramic.
Dan

hi
welcome

i use single ended for all testing so that opamps have no bearing on results

probably use all film smd caps

i cant see myself brave enough to venture into the 4v regulation

im not using the same i2s device as before so i need to get testing with another amanero

[Dan155]

Thanks for the welcome and the reply.

The opamps I'm referring to are those buffering the 4V references, not the output parts. Looking at the board, I suspect they are the 5 pin parts on the other side of the resistor ladder to the 5V regulators.

I don't have the DAC yet, I'm trying to discipline myself to finish a couple of other projects before going for a shiny new toy. But my willpower is failing! Enjoying readinh your and others' experiences with modding, and plan to do some of my own.

[nige2000]

Thanks for the welcome and the reply.

The opamps I'm referring to are those buffering the 4V references, not the output parts. Looking at the board, I suspect they are the 5 pin parts on the other side of the resistor ladder to the 5V regulators.

ah ok
that would make more sense
ill try and probe the 5 pin sot

I don't have the DAC yet, I'mtrying to discipline myself to finish a couple of other projects before going for a shiny new toy. But my willpower is failing! Enjoying readinh your and others' experiences with modding, and plan to do some of my own.

yea would be difficult not to experiment with this dac
i have many projects not finished myself
im hopeful that this will be one of the best dacs ive heard to date with some modding/filters

whats the plan for the 4 volt reference?

[nige2000]

output opamps gone
5v reg caps changed to lower value film
cleaner sharper more atmosphere
levels of detail ive not heard before

looking forward to taking off the bigger caps ;)
well having them gone anyway
there a pita to remove

[sima66]

Maybe this will be useful for the project:
http://www.partsconnexion.com/t/eblast/2015/cc/ccw.html

[Dan155]

would be difficult not to experiment with this dac
i have many projects not finished myself
im hopeful that this will be one of the best dacs ive heard to date with some modding/filters

whats the plan for the 4 volt reference?

Ah, sorry I didn't see this question until now. I just want to see exactly how the references are implemented, such as how much filktering is done - the positive ref is created by an inverter which will have switching noise - and whether ceramic or film caps are used. I'd also like to see the specs (PSRR, noise etc.) for the opamps used for driving the 4V rails.

What type of film caps did you use on the 5V rails?

[nige2000]

i had these lying about
i like em anyway and lifepo4 is pretty forgiving about this sort of stuff
http://ie.farnell.com/cornell-dubilier/ ... dp/2112915


anyway ive replaced all electrolytic caps
its ready for critical listening and comparative testing vs the big boys
sounds really good fluid and more detailed than ive heard before
of course theres more that can be done but im going to leave it like this for a while
at least for a few days :)

[nige2000]

[rickmcinnis]

nige2000,

I am confused by your replacing the electrolytics with film caps.

I would have thought you would not have wanted any capacitance at all?

Did you try it without any caps?

With the long weekend I am finally going to butcher my board! No electrolytics and no output opamps.

Planning on using a heat gun - did you use a soldering iron?

As far as removing those caps - I think I will destroy them - pull the "tops" off and get better access to the pads. No intention of ever re-using them. Should make the job easier, especially if I chicken out on using the heat gun.

It is so gratifying to watch those things pop off the board ...

While I am at it - have you tried using an old video card to relieve the CPU of video duties? One of "serge's" tricks from the cMP days. Finally got around to doing it again and it seems to be worthwhile. Now I can remove all of the video chips from the MB, along with the audio chips.