ES9018 32bit Audio DAC kit USD89.95

[qusp]

Socrates' version may be closer to the truth, but I find Einstein's version somewhat more motivational.

[KlipschKid]

Originally Posted by hochopeper

And all of this, dear friends, is why it is actually best to buy a pcb designed by someone who knows what they're doing rather than just the cheapest pcb that takes the DAC chip that you think you want. The datasheet pcb design is the minimum standard to achieve IMO. I know I am flogging a dead horse here, but, why exactly did qusp need to explain all that is wrong with a flawed product? Why did he need to spend HOURS writing all of that stuff that is nothing more than repeating publicly available information on the DAC implementation and basic PCB design principles? As he's admitted there is still plenty to PCB design improvements that are left to implement after the changes he has suggested.

Again, you're just having a rant. Anyone would think Brisbane is a horrible place to live the way you go on. What's the excuse this time ? Got a hangover ?

[qusp]

no, maybe just a healthier dose of realism in the sunshine over here? i'll tell you whats getting boring, the lame 'must be drunk' 'must have a hangover' defensive cheap shots you keep spouting.

honestly I dont know how the design can be defended, it showed a fundamental misunderstanding of fairly basic design and electronics principles. It went against nearly all the recommendations in the document the schematic copied from (the document from another dac...) not because he thought he knew better, rather just didnt know.... which leads one to believe it was not understood.

just about all those quotes about the ground plane, those are all on one page, the page with the recommended layout on it.

this stuff should be taken care of on prototype PCBs, the customer and onlookers should not be paying for such elementary mistakes.

just about the only participation I have seen from the OP has been promoting his designs here, right down to the user name chosen. I guess I just dont like seeing members here paying for companies R&D in money and time.

[qusp]

so sad... I will miss our talks

[glt]

Notwithstanding the strong desire to see this product fail, I am not throwing mine away and may buy more in the future. For $99 bucks it is great product. As I said before, no one is claiming that this product will surpass Acko and Buffalo and no one is expecting that either. But is has the right to exist and some people (like me) wishes it to improve.

On top of that, it is a great board for diy and to learn. For example, I learned about capacitors sizes and their effect on bypass.

All the argument about its flaws made me study the ess layout artwork to understand more about grounding and power.

etc...

In the meantime, I overlayed the art work found in the ESS docs. This is what I understand:

The power planes are on the top plane: one half is one polarity, the other half is the other polarity. All the signal components for the opamps are laid out in the middle and completely surrounded by the power planes. If it is not good to cross a power line, then it is probably not good to be running along power planes.

The ground plane is in the bottom. It is interrupted by the traces around and under the opamps and completely open and clear in the areas outside of the opamps. So it is not fully solid.

[qusp]

no, you are incorrect. the top is segmented power as you suggest (and as I said), but the traces for signal travel part way along the top surrounded by solid power plane (which actually isnt a problem) but are all the while having ground plane underneath them. then they travel for a short length to the IV resistor and filter, then back down to the bottom as part of the opamp feedback loop 15-20mm, which is surrounded completely by ground plane and does not block any (line of sight) return path back to the dac. The rest is on top

the blue traces are the only ones on the bottom in the ground plane.. there is no middle layer

and in answer to your earlier question, return currents where do they come from? the opamp power supply rails, the dac itself and ground. In most circuits the decoupling caps are part of the signal current loop. that is how you can have designs like this cute novelty posted by shinja here



I dont know how many times I must repeat this, the signal lines should traverse an unbroken ground plane where possible. the return currents should be able to traverse a line of sight return back to the dac. that is what they have done, there is nothing blocking that, there is little on the bottom at all, but nothing blocking that. Compared to almost the entire width being cut twice from one side to the other, I think we can forgive that given the 2 layer PCB.

its a 2 layer PCB, of that i'm 99% certain. check out the 2 channel 9018 eval board posted in the thread on the first page at the moment. its almost identical to the 8 channel layout and you can see planes on top with a good number of signal traces too.

you mistake my wanting the design to be more than a prototype before going on sale, ignoring or dismissing real problems with the design, with wanting it to fail. $99 or not, besides it keeps growing and once you add everything to complete it....

[glt]

Originally Posted by qusp

...


I dont know how many times I must repeat this, the signal lines should traverse an unbroken ground plane where possible. ....

But the lines ARE traversing the power planes. The connecting line under the board traverses the +V to the -V (or - to +) which are on top of the board. In this board the signal line which is on the top, traverses the power lines which are on the bottom.

I would say that the ESS layout is pretty clever: rather than ground fill, it is power plane fill. Haven't seen that before, and it allows for a two layer board.

I have seen people reviewing the eval board connected to switching supplies (which in the eval board the power planes surround everything) and the results are good.

[qusp]

record on repeat. there are no specific return currents to worry about blocking here and the traces are completely surrounded by ground plane and it is after the IV resistor.

glt, its clear you dont understand the circuit either, or what the problem is with it.

i'm out, enjoy!

[glt]

Originally Posted by qusp

...

glt, its clear you dont understand the circuit either, or what the problem is with it.

...

I certainly don't buy that.

[Odysseas]

guys I do understand what you are saying about mistakes in basic principles but in god's name it's only 100$! For me and I suppose for a lot of people that is FINALLY good news! Enough with the "monopoly" and rediculous money asked for a board......and yes I do know about R&D and the cost of production etc and that all raise the cost of the final board. But come on....
Let's just hope that the designer will take your advices into consideration and apply them...