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Old 5th March 2006, 10:41 PM   #1211
Dr.Gone is offline Dr.Gone  Netherlands
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Default Re: Re: Clocks and clock psu

Quote:
Originally posted by awpagan

use the earth plane for digital separate from analogue, star grd common.

allan
also
you mean there allready is a star ground on the CD-63/67?

I don't get it?!?


Regards,
Jacco

btw. I'm waiting for my XO2 by tentlabs for my CD-63 any tips for that clock? I have done a mix of ray's and bobwire's mods on my cd-63 (but only with caution: I have NOT replaced any bipolars/ceramics with polar elco's)
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Old 6th March 2006, 03:03 AM   #1212
awpagan is offline awpagan  Australia
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Default Re: Re: Re: Clocks and clock psu

Quote:
Originally posted by Dr.Gone


you mean there allready is a star ground on the CD-63/67?

I don't get it?!?


Regards,
Jacco

btw. I'm waiting for my XO2 by tentlabs for my CD-63 any tips for that clock? I have done a mix of ray's and bobwire's mods on my cd-63 (but only with caution: I have NOT replaced any bipolars/ceramics with polar elco's)
star ground???????

standard form
it uses the top plane as a large earth plate
all analogue and digital have links to it.
uses neutral as earth, via transformer
only way to only way to earth is through the transformer, or any other connected equipment via rca ground

May solve external ground loops?
but at what cost?

probably why i use iec plug

allan
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Old 6th March 2006, 07:57 AM   #1213
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Quote:
Originally posted by 6h5c


Hi Brent,

Well, I read all this wisdom in the datasheet, nothing fancy...

The proposed value for R1 is 120R. The 1.25V reference voltage is across this resistor, so there will be a little over 10mA idle current drawn, which is the minimum load current for the regulator to maintain regulation. So that takes care of that. It won't hurt to use 100R.

If you calculate the bypass cap according to C = 1/(2*pi*f*R) you will get 13uF at a ripple frequency of 100Hz and 120R. So your cap is a bit on the low side.

Regards,

Ray.
Cheers Ray. Ill mess about with the values a little.
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Old 6th March 2006, 08:37 AM   #1214
6h5c is offline 6h5c  Netherlands
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Default Re: Clocks and clock psu

Quote:
Originally posted by Dr.Gone
you mean there allready is a star ground on the CD-63/67?

I don't get it?!?

Regards,
Jacco
Hi Jacco,

There is a star-ground at the RCA socket. This is a point where all the ground traces from the board meet. The top ground-plane is grounded at this same star-point, but it is also connected through several links to local (analog and digital) groundpoints at the DAC, decoder and analog +/-12V supply caps (U221, U235, U169, U208, U267, U136). So it seems things are not strictly separated. By removing the links (except the one at the star-point) the ground-plane becomes separated.
You should leave U136 in place if you want to keep using the headphone circuit by the way. It has no trace to ground on the bottom layer, so it is the only ground path for it.

Regards,

Ray.
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Old 6th March 2006, 08:42 AM   #1215
6h5c is offline 6h5c  Netherlands
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Default Re: Clocks and clock psu

Quote:
Originally posted by awpagan
uses neutral as earth, via transformer
only way to only way to earth is through the transformer, or any other connected equipment via rca ground

allan
Hi Allan,

What do you mean by "uses neutral as earth, via transformer"?
Is the neutral of the primairy side connected to the board ground in your player??

Regards,

Ray.
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Old 6th March 2006, 09:30 AM   #1216
awpagan is offline awpagan  Australia
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Default Re: Re: Clocks and clock psu

Quote:
Originally posted by 6h5c


Hi Allan,

What do you mean by "uses neutral as earth, via transformer"?
Is the neutral of the primairy side connected to the board ground in your player??

Regards,

Ray.

Ray
i have question
we need active and neutral or positive and earth
for any circiut to operate
standard config, where's earth

allan
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Old 6th March 2006, 09:42 AM   #1217
6h5c is offline 6h5c  Netherlands
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Hi Allan,

In my house, the neutral of the 230V outlet is connected to earth near the main fuse in the fusebox. But the player is floating with respect to earth normally, since the secondairy circuit is by no means connected to the primairy, or grounded.

So neutral = earth over here, but the flat 230V euro-plugs are unidirectional, so there's no telling which wire will be connected to what once you plug it in.

What plugs do you use over there, is it like the british plugs? That way you would always be sure which wire is hot and which is neutral, if the socket is wired correctly that is....

That's why I wondered: is the neutral of the primairy side somehow connected to the board ground in your player?

Regards,

Ray.
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Old 6th March 2006, 09:43 AM   #1218
poynton is offline poynton  United Kingdom
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Default Re: Re: Re: Clocks and clock psu

Quote:
Originally posted by awpagan



Ray
i have question
we need active and neutral or positive and earth
for any circiut to operate
standard config, where's earth

allan
Most modern electrical equipment does not require an earth since it is 'double-insulated'.

The requirement for mains powered equipment is therefore only LINE and RETURN (Neutral). ( although with figure 8 connectors ????)

Theoretically, earthing audio equipment is not required. Indeed, earth loops may / will be formed as we are linking several pieces together.

The 'usual' solution is to connect the amplifier chassis to mains ground, hence the provision of an earthing lug close to the inputs.

All other equipment should be connected to this point, forming a sort of star.

Incidentally, if the piece of equipment does not have a connection to earth, there is little point in having an input noise filter ( see my earlier post ).

Andy
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Old 6th March 2006, 10:11 AM   #1219
awpagan is offline awpagan  Australia
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Ray
That's what i mean
active & neutral (earth)
AC in transformer, which side is more negative?

andy's right
floating earth in circuit or on pcb
and we are trying to remove mV of noise?


Standard in aust is neutral is either connected to earth at fusebox or
at substation


allan
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Old 6th March 2006, 10:19 AM   #1220
poynton is offline poynton  United Kingdom
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Quote:
Originally posted by awpagan
Ray
That's what i mean
active & neutral (earth)
AC in transformer, which side is more negative?

andy's right
floating earth in circuit or on pcb
and we are trying to remove mV of noise?


Standard in aust is neutral is either connected to earth at fusebox or
at substation


allan

In the UK, Neutral ( return ) is grounded at the substation.

The EARTH wire should be connected at the fuse box to all cold water pipes via earth bonding straps and then to earth by the water system. This was great in the days of lead water piping but with the advent of plastic feed from the main supply and plastic push-fit pipes internally, maybe an Earth stake rammed into the ground is a good idea. After all, that's what happened in the good old days of crystal sets !!

Andy
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