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Old 26th December 2012, 09:58 AM   #4681
SSerg is offline SSerg  Russian Federation
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Hi, wlowes
Quote:
Originally Posted by wlowes View Post
Would it not be better to use a pcb that has most of the chip floating in the air?
This is useful with standpoint of the improvement to insulation, but can enlarge the stray montage capacities.
I think that at given aspect it is more important to pay attention to DEM capacitor insulation.
It is necessary to choose the capacitors with maximum resistance of the insulation, let in the prejudice of the other parameter even.
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Old 26th December 2012, 10:04 AM   #4682
SSerg is offline SSerg  Russian Federation
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Hi, qusp
Quote:
Originally Posted by qusp View Post
Parasitic leakage will find a way even without a PCB, without a PCB and ground, EMC noise from the i2s and clock signals will have a whale of a time jumping all over the place. depending on speeds they dont even need a conductor to travel on.
It is important for correct working of DEM cells low capacitor leakage of at DC. But you talk about electromagnetic hindrances, which are connected with AC. Of course, advisable reduce these hindrances. But here talk about the other.

Last edited by SSerg; 26th December 2012 at 10:17 AM.
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Old 26th December 2012, 11:22 AM   #4683
qusp is offline qusp  Australia
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no, it is not just connected to AC, it is connected to i2s, a fast analogue signal used to transmit digital, so kinda AC if you want to look at it that way. fast signals without proper layout/grounding = EMC issues. No i'm not talking about 'other' I also wasnt really talking about capacitors, so I really have no idea what you are talking about....

basically, I know what I was saying, either you didnt understand..or you didnt understand.... and about your post...I didnt understand....

Last edited by qusp; 26th December 2012 at 11:30 AM.
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Old 27th December 2012, 12:17 PM   #4684
SSerg is offline SSerg  Russian Federation
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Hi, qusp
Quote:
Originally Posted by qusp View Post
basically, I know what I was saying, either you didnt understand..or you didnt understand.... and about your post...I didnt understand....
We have not understood each other. I spoke about the DEM capacitor insulation on direct current, but you spoke of electromagnetic hindrances. This is a separate subject.
Let's return towards the insulation quality of the DEM capacitor.Why this it is important? Because leakages of DEM capacitors on direct current (on DC) break the exact double difference of bit currents at nearby bits. This brings appearance of distortion at analog signal.
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Old 27th December 2012, 02:29 PM   #4685
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Serg,
I assume from this that Styrene, Teflon or Propylene capacitors for the DEM oscilator are recommended, yes?
__________________
... jh
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Old 27th December 2012, 02:59 PM   #4686
roger57 is offline roger57  Canada
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Quote:
Originally Posted by qusp View Post
no, it is not just connected to AC, it is connected to i2s, a fast analogue signal...

Oh, really? I2S, a fast analogue signal? "Contributing" this kind of feedback seems a bit counterproductive. BTW, no guilt saying that.

Just in case you need a bit of background on this new digital stuff, here you go:
http://en.wikipedia.org/wiki/I%C2%B2S

Last edited by roger57; 27th December 2012 at 03:02 PM.
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Old 27th December 2012, 03:54 PM   #4687
qusp is offline qusp  Australia
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haha man how childish can you be....

seems you completely misunderstood the post, but that doesnt surprise me

I was replying to wlowes suggestion that by removing the PCB you would lower the leakages and improve the decoupling by reminding that without a low impedance ground/ ground plane, the fast signals would cause other EM related leakages

yeah clock wave is sooo digital isnt it? the interpretation is digital, the wave that represents it is not

I suggest you go back and hit the books while I make you disappear

Last edited by qusp; 27th December 2012 at 03:59 PM.
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Old 27th December 2012, 04:02 PM   #4688
roger57 is offline roger57  Canada
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Quote:
Originally Posted by qusp View Post
haha man how childish can you be....

seems you completely misunderstood the post, but that doesnt surprise me

I was replying to wlowes suggestion that by removing the PCB you would lower the leakages and improve the decoupling by reminding that without a low impedance ground plane the fast signals would cause other EM related leakages

yeah clock wave is sooo digital isnt it? the interpretation is digital, the wave that represents it is not

I suggest you go back and hit the books while I make you disappear

Quote (again) what you wrote..."... it is connected to i2s, a fast analogue signal."

Whatever. I guess I'll get back to my childish Grade 2 reading primer to try and wrap my head around sentence structure.
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Old 28th December 2012, 07:00 AM   #4689
SSerg is offline SSerg  Russian Federation
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Hi, jameshillj
Quote:
Originally Posted by jameshillj View Post
Serg,
I assume from this that Styrene, Teflon or Propylene capacitors for the DEM oscilator are recommended, yes?
Yes, these capacitors have pretty good insulation, but rather greater size and stray inductance too. The bulky capacitors it is difficult to place and they sensitive to external hindrance.
May suit and ceramic capacitors with good insulation and with enough big working voltage (100V, 250 V and more). The ceramic capacitor inductance is small.
How see, choice of the type capacitor - not open-and-shut case. Here needs the compromise.
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Old 28th December 2012, 07:46 PM   #4690
regal is offline regal  United States
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Quote:
Originally Posted by qusp View Post
haha man how childish can you be....

seems you completely misunderstood the post, but that doesnt surprise me

I was replying to wlowes suggestion that by removing the PCB you would lower the leakages and improve the decoupling by reminding that without a low impedance ground/ ground plane, the fast signals would cause other EM related leakages

yeah clock wave is sooo digital isnt it? the interpretation is digital, the wave that represents it is not

I suggest you go back and hit the books while I make you disappear

Why is it so hard for people to understand that any digital signal transmission is an analog? Its just basic physics.

As far as the PCB-less TDA1541, the concept is you build it point to point in three dimensions on a copper ground plane , Thorsten calls it "bug" building. The results are aesthetically ugly and not commercially viable but make a lot of "sense" on a science/engineering level, perfect for DIY This is why you see little innovation/offerings of TDA1541 PCB's other than the silly china offerings, they just don't make a lot of sense any more.
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