This is not the usual question you see on this forum, but here goes anyway.

I'm translating a review of an SACD player (from German) and I can't for the
life of me figure out what the reviewer is trying to say in one particular
section. He's describing the player's balanced output, and says something
like:

".... balanced circuitry, which uses sophisticated filtering to ensure that
the signal is not connected to ground in the normal way along with the high
frequency residual part of the digital signal (since this has a detrimental
affect when it travels around the rest of the hi-fi system), but is
transposed in common mode at the output."

Can anyone make sense of this?

Stephen

On Sun, 19 Sep 2004 23:02:13 +0100, "Stephen McLuckie"
wrote:

I'm translating a review of an SACD player (from German) and I can't for the
life of me figure out what the reviewer is trying to say in one particular
section. He's describing the player's balanced output, and says something
like:

".... balanced circuitry, which uses sophisticated filtering to ensure that
the signal is not connected to ground in the normal way along with the high
frequency residual part of the digital signal (since this has a detrimental
affect when it travels around the rest of the hi-fi system), but is
transposed in common mode at the output."

Can anyone make sense of this?

They are planning to march into Poland again :-)

Stephen McLuckie wrote:

This is not the usual question you see on this forum, but here goes anyway.

I'm translating a review of an SACD player (from German) and I can't for the
life of me figure out what the reviewer is trying to say in one particular
section. He's describing the player's balanced output, and says something
like:

".... balanced circuitry, which uses sophisticated filtering to ensure that
the signal is not connected to ground in the normal way along with the high
frequency residual part of the digital signal (since this has a detrimental
affect when it travels around the rest of the hi-fi system), but is
transposed in common mode at the output."

Can anyone make sense of this?

It's rubbish speak.

Balanced circuitry has two signal carrying paths of opposite polarity, mainly to
avoid noise pickup that is picked up equally *in phase* by both signal paths (
common mode interference ).

Balanced circuitry does *not* have " sophisticated filtering to ensure that the
signal is not connected to ground in the normal way ".

I suspect he may have been referring to a DAC output. These often have
differential ( or balanced if you like ) outputs that then require connection to
a low-pass filter.

If the following low-pass 'anti-aliasing filter' has a balanced input, it will
reject any common-mode noise ( i.e. noise that appears *in phase* on both the
outputs of the DAC ) caused by the chip itself or poor pcb layout.

I have implemented several of these.

The reviewer certainly doesn't know how to express himself intelligently !


Graham

"Stephen McLuckie" wrote:

This is not the usual question you see on this forum, but here goes
anyway.

I'm translating a review of an SACD player (from German) and I can't
for the life of me figure out what the reviewer is trying to say in
one particular section. He's describing the player's balanced output,
and says something like:

".... balanced circuitry,

Balanced output

which uses sophisticated filtering to ensure
that the signal is not connected to ground in the normal way along
with the high frequency residual part of the digital signal (since
this has a detrimental affect when it travels around the rest of the
hi-fi system),

isn't referenced to ground. Since the digital stages are, then you may
be carrying "noise" on that ground to other components (which is not
likely in quality components)

but is transposed in common mode at the output."


balanced output, not referenced to ground.

Can anyone make sense of this?

Stephen



advertising babble to impress you with the output stage of this device.

"Stephen McLuckie" wrote ...
This is not the usual question you see on this forum, but here goes
anyway.

I'm translating a review of an SACD player (from German) and I can't for
the
life of me figure out what the reviewer is trying to say in one particular
section. He's describing the player's balanced output, and says something
like:

".... balanced circuitry, which uses sophisticated filtering to ensure
that
the signal is not connected to ground in the normal way along with the
high
frequency residual part of the digital signal (since this has a
detrimental
affect when it travels around the rest of the hi-fi system), but is
transposed in common mode at the output."

Can anyone make sense of this?

If you required to preserve the marketing babble in your English
translation then your text seems opaque and meaningless enough to
appeal to the dilletentes who have more dollars than sense. :-)

OTOH, your question would appear to indicate that you recognize
that it is rubbish. Hopefully you have the opportunity to clarify it.

It may take nothing more than saying that it has a balanced output.
Perhaps adding a sentence or two describing the actual advantages
of balanced lines would be appropriate (or not, depending on the
projected audience?)

On Mon, 20 Sep 2004 00:02:13 +0100, Pooh Bear
wrote:

Stephen McLuckie wrote:

This is not the usual question you see on this forum, but here goes anyway.

I'm translating a review of an SACD player (from German) and I can't for the
life of me figure out what the reviewer is trying to say in one particular
section. He's describing the player's balanced output, and says something
like:

".... balanced circuitry, which uses sophisticated filtering to ensure that
the signal is not connected to ground in the normal way along with the high
frequency residual part of the digital signal (since this has a detrimental
affect when it travels around the rest of the hi-fi system), but is
transposed in common mode at the output."

Can anyone make sense of this?

It's rubbish speak.

Balanced circuitry has two signal carrying paths of opposite polarity, mainly to
avoid noise pickup that is picked up equally *in phase* by both signal paths (
common mode interference ).

Balanced circuitry does *not* have " sophisticated filtering to ensure that the
signal is not connected to ground in the normal way ".

I suspect he may have been referring to a DAC output. These often have
differential ( or balanced if you like ) outputs that then require connection to
a low-pass filter.

If the following low-pass 'anti-aliasing filter' has a balanced input, it will
reject any common-mode noise ( i.e. noise that appears *in phase* on both the
outputs of the DAC ) caused by the chip itself or poor pcb layout.

That sounds about right, although strictly speaking it's an
anti-imaging filter in a DAC, anti-aliasing filters belong in ADCs.

I have implemented several of these.

The reviewer certainly doesn't know how to express himself intelligently !

More likely he simply doesn't understand the technology, as is common
with audio reviewers. :-(
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sun, 19 Sep 2004 23:02:13 +0100, "Stephen McLuckie"
wrote:

This is not the usual question you see on this forum, but here goes anyway.

I'm translating a review of an SACD player (from German) and I can't for the
life of me figure out what the reviewer is trying to say in one particular
section. He's describing the player's balanced output, and says something
like:

".... balanced circuitry, which uses sophisticated filtering to ensure that
the signal is not connected to ground in the normal way along with the high
frequency residual part of the digital signal (since this has a detrimental
affect when it travels around the rest of the hi-fi system), but is
transposed in common mode at the output."

Can anyone make sense of this?

If that's a literal translation, it may simply be that technical
German has its own peculiarities! What he's trying to say is that the
player uses a pair of DAC chips in differential mode, feeding a
reconstruction filter which has a differential input, so that any
'rubbish' which is common to the output lines of both DACs (common
mode) will appear in phase at the input of the reconstruction filter,
and will be rejected (common mode rejection ratio, or CMRR is a
standard specification for differential devices), while the antiphase
DAC outputs will be passed through the reconstruction filter, and will
appear at the output in a cleaner form than would otherwise be the
case.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Brilliant! Thanks for all the explanations. The description is indeed, as
you recognized, of the DAC output. I have now been able to rewrite this so
that it makes sense. I think the problem was both my lack of expertise and
the writer's inability to express himself clearly. It doesn't sound as if he
understood what was going on either, but was just repeating a garbled
version of what he had been told by the designer.

Stephen