Soekris' DAC implementations

[ristar]

I made a simple circuit to keep a relay powered that has NC contacts shunting the output when the coil is off, the relay only engages when the DAC has a solid LED output (lock) and the input voltage from the +/-12V power supply is good.

End result, no more speaker pops/crackles during sample rate changes , has a good delayed power on function since the DAM takes a bit of time to boot/lock at powerup, and the poweroff PLOP happens after the relay has already shunted the output.

I can do a schematic later but its just a simple rise/falltime config that feeds an NPN darlington that acts as the 12V coil switch and a normal jellybean NPN used to invert the LED output along with some resistors, diodes and a capacitor. I simply power it off one of the legs of DC power input.

Sounds great! Looking forward to this... Was intending to use arduino to do this once dimdim/glt come up with the core code.

 

[DEQ+TheEnd]

I made a simple circuit to keep a relay powered that has NC contacts shunting the output when the coil is off, the relay only engages when the DAC has a solid LED output (lock) and the input voltage from the +/-12V power supply is good.

End result, no more speaker pops/crackles during sample rate changes , has a good delayed power on function since the DAM takes a bit of time to boot/lock at powerup, and the poweroff PLOP happens after the relay has already shunted the output.

I can do a schematic later but its just a simple rise/falltime config that feeds an NPN darlington that acts as the 12V coil switch and a normal jellybean NPN used to invert the LED output along with some resistors, diodes and a capacitor. I simply power it off one of the legs of DC power input.

That would be great!

 

[PanagiotisPapadakos]

Anyone believe the LVC595’s could benefit from being thermally connected?

I’ve read somewhere that early R-2R test done by others had problems with uneven on resistance in the 595 device used in their early implementation. Of course the LVC version used here is of much higher quality and If I remember correctly Søren measured switching speed at 70us.

What I’m thinking is a thin sheet of copper covering all the resistors and LVC595’s. With double sided thermal stickers on each LVC.

Hi DEQ+TheEnd. Did you try the idea with the copper?

 

[DEQ+TheEnd]

Hi PanagiotisPapadakos.

No I’ve decided I’m not doing any hardware modifications until filters are sorted out and Soren release firmware including intended functionality. Don’t want to paint me in a corner before all the walls are in place.

 

[spzzzzkt]

No I’ve decided I’m not doing any hardware modifications until filters are sorted out and Soren release firmware including intended functionality. Don’t want to paint me in a corner before all the walls are in place.

x2. I'm not prepared to commit to a final hook-up scheme until the dual mono functionality is documented and released. The next firmware release should hopefully eliminate a lot of the unknowns.

I had been looking at the Lundahl transformer options for balanced out but kept coming back to the point that the outlay is roughly the same as buying a second DAM to run a dual mono setup.

 

[Bones13]

x2. I'm not prepared to commit to a final hook-up scheme until the dual mono functionality is documented and released. The next firmware release should hopefully eliminate a lot of the unknowns.

I had been looking at the Lundahl transformer options for balanced out but kept coming back to the point that the outlay is roughly the same as buying a second DAM to run a dual mono setup.

Which transformers were you considering?

 

[TNT]

I belive this DAC is (as all are more or less) sensitive to acuostical and mechanical feedback. So it should be put into a non vibrating enclosure which is sealed to the outside sound presure. A non metallic one reduce the interference with the signal. Don't use those big bulky metallic boutique connectors - they kill dynamics and and put a low roof on the soundstage. Use single solid core teflon isolated wire.

//

 

[laptopav]

I belive this DAC is (as all are more or less) sensitive to acuostical and mechanical feedback. So it should be put into a non vibrating enclosure which is sealed to the outside sound presure. A non metallic one reduce the interference with the signal. Don't use those big bulky metallic boutique connectors - they kill dynamics and and put a low roof on the soundstage. Use single solid core teflon isolated wire.

//

I am new to DAC, this is my first DAC but feel your idea very interesting!

Do you think which parts of DAC is sensitive with vibrating/sound? Can we cover that specific parts by sound isolate material?

 

[TNT]

Maybe - but one should be aware of that if something is placed on actual components, that may have adverse electrical effects in itself. The crystal that makes the oscillator is sensitive. Then there seem to be indications that the actual resistors in the array is also sensitive.

//

 

[PanagiotisPapadakos]

Maybe - but one should be aware of that if something is placed on actual components, that may have adverse electrical effects in itself. The crystal that makes the oscillator is sensitive. Then there seem to be indications that the actual resistors in the array is also sensitive.

//

I have used some blu-tak under the PCB and over the crystals for both the DAC and my CM6631a card as damping material. I am not sure if it has any effect, since I've been listening the dac like this from the beginning.

 

[spzzzzkt]

Here's a nice open source design which will bring a substantial improvement to SQ.

It works best if you use cryo'd Russian NOS 99.9999999% pure silver foil.

Purists should choose the Nelson variation for obvious reasons.

 

[spzzzzkt]

Which transformers were you considering?

Considered, as in briefly thought about, had a scan through the Jensen and Lundhal catalogs then checked the price on items that looked as though they might work and then dismissed the idea. I hadn't really gone much further than that.

 

[TNT]

I have used some blu-tak under the PCB and over the crystals for both the DAC and my CM6631a card as damping material. I am not sure if it has any effect, since I've been listening the dac like this from the beginning.

Damping the oscilator and board is most probably a good idea. No tin-foil-hat aspects in doing that.

//

 

[DEQ+TheEnd]

Isn't this easy to test by simply tapping the clock while hocked up to the measurement rig?.

 

[PanagiotisPapadakos]

I am also planning to do what is suggested here: Vibration control for better performance

 

[wlowes]

can someone point me to how it sounds?

sorry to be off topic. I see several threads with combined hundreds of posts.

can someone point me to any and all posts explaining how it sounds? compared to tda1541a for example

I have scanned several threads but yet to see where people actually talk about how it sounds. Thanks for your indulgence

 

[robertrowett]

sorry to be off topic. I see several threads with combined hundreds of posts.

can someone point me to any and all posts explaining how it sounds? compared to tda1541a for example

I have scanned several threads but yet to see where people actually talk about how it sounds. Thanks for your indulgence

What would you say TDA 1541a sounds like? The dam1021 is so dependent on implementation that its tough to compare without context. Power and filters completely change the presentation. I would say that soundstage, precision, and dynamics are the most obvious and universal assets of this dac. It is never boring and the midrange can especially draw me in. beyond that, again... filters, power and output stage will depend on your system and taste. To me it brings to mind 1541 or pcm63 depending on implementation... many who like those will like this too. Coming from a line of r2r dacs, this is a new level for me.

 

[Chris1967]

What would you say TDA 1541a sounds like? The dam1021 is so dependent on implementation that its tough to compare without context. Power and filters completely change the presentation. I would say that soundstage, precision, and dynamics are the most obvious and universal assets of this dac. It is never boring and the midrange can especially draw me in. beyond that, again... filters, power and output stage will depend on your system and taste. To me it brings to mind 1541 or pcm63 depending on implementation... many who like those will like this too. Coming from a line of r2r dacs, this is a new level for me.

I find it lacking in dynamics and top end (compared to ESS9018 Bufalo and AKM4396 JLSounds) implementations that i have and heard), can you please tell me compared to which of your implementations do you find that it has better dynamics?

 

[wlowes]

What does a 1541a sound like?

You are right, that is kind of a 'how long is a piece of string?' kind of question.
I find a well implemented 1541a (clean power, discrete regs, well done layout) is very clear and clean, natural without the crisp digital signature of many traditional cd players.
Thanks for your impressions. This is an interesting project.

 

[Stixx]

can someone point me to any and all posts explaining how it sounds?

I have my DAM playing for a week now, connected via I2S (very recommended) with a simple DC psu for the moment, using the unbuffered outputs and into either a Dynahi headphone amplifier and HE-500 or a C3G SET headphone amplifier and slightly modded Senn HD800.

My impressions are: it's clinically precise without sounding clinical. It has some of the best treble I have ever had from a DAC. It has enormous detail so that even with headphones I have excellent room information. It seems very true to the source... it doesn't add or it doesn't leave away. In fact it seems to me that some are critizising it for not having something they are used to from other DAC's... like aggressive treble. DAM has no sibilance at all and to my ears no "digital" footprint. Presentation can be slightly in your face (but not annoying even with HD800), but then I have all the filters to try.