sci.electronics.repair@googlegroups.com

Today's topics:

* Two phases or not? - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
* Datasheet required STK795-820 or 821 - 3 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/632acd16eeba7502?hl=en
* DTV sound synch - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/2896d12048fef530?hl=en
* Yamaha EMX5016 mixer amp from 2006 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/bc288deddd9278ea?hl=en

==============================================================================
TOPIC: Two phases or not?
http://groups.google.com/group/sci.electronics.repair/t/0a29a801d6e01e9e?hl=en
==============================================================================

== 1 of 3 ==
Date: Fri, Jan 28 2011 12:51 pm
From: "Phil Allison"

"William Sommerwerck"

> "Phase" implies a relative-timing relationship.

** The term " phase shift " generally has that implication - but not the
term " phase " alone.

> Simply inverting polarity doesn't change the timing between the two
> waveforms.

** Irrelevant - see above.

In any case, for continuous sinewaves a 180 degree phase shift and signal
polarity inversion are completely indistinguishable.

.... Phil

== 2 of 3 ==
Date: Fri, Jan 28 2011 8:03 pm
From: David Nebenzahl

On 1/28/2011 11:28 AM Mark Cross spake thus:

> David Nebenzahl wrote:
>
>> So what's "special" or magic about 180° that it wouldn't be considered a
>> completely separate and distinct phase? Why would phase have a "hole" at
>> 180°? (And for any wisenheimers who will say "well, you must consider 0°
>> to be a separate phase too!" I say nonsense: that's just a phase
>> "identity" which we can ignore as being identical to the original phase.)
>
> Repeat the hypothesis a 0º and you will find a hole in there, much the same
> as there must be one at 180º.

I don't think so. At 0º, the two waveforms are *identical*, so that's
the degenerate case.

> To understand what is "magical" about that you will need to know phasors and
> the math related to that. Once you understand the math that support phasors,
> you clearly see why 0º and 180º are the same phasor.
>
> http://en.wikipedia.org/wiki/Phasor

Sorry, I don't use Wikipedia as a source of credible information.

But even if 0º and 180º are the same phasor, they're still completely
different waveforms, which is the important thing here, isn't it?

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 3 of 3 ==
Date: Fri, Jan 28 2011 8:28 pm
From: Mark Cross

David Nebenzahl wrote:

> On 1/28/2011 11:28 AM Mark Cross spake thus:
>
>> David Nebenzahl wrote:
>>
>>> So what's "special" or magic about 180° that it wouldn't be considered a
>>> completely separate and distinct phase? Why would phase have a "hole" at
>>> 180°? (And for any wisenheimers who will say "well, you must consider 0°
>>> to be a separate phase too!" I say nonsense: that's just a phase
>>> "identity" which we can ignore as being identical to the original
>>> phase.)
>>
>> Repeat the hypothesis a 0º and you will find a hole in there, much the
>> same as there must be one at 180º.
>
> I don't think so. At 0º, the two waveforms are *identical*, so that's
> the degenerate case.
>
>> To understand what is "magical" about that you will need to know phasors
>> and the math related to that. Once you understand the math that support
>> phasors, you clearly see why 0º and 180º are the same phasor.
>>
>> http://en.wikipedia.org/wiki/Phasor
>
> Sorry, I don't use Wikipedia as a source of credible information.

Open your mind.

> But even if 0º and 180º are the same phasor, they're still completely
> different waveforms, which is the important thing here, isn't it?

No.

--
Mark Cross
If Linux doesn't have the solution, you have the wrong problem.

==============================================================================
TOPIC: Datasheet required STK795-820 or 821
http://groups.google.com/group/sci.electronics.repair/t/632acd16eeba7502?hl=en
==============================================================================

== 1 of 3 ==
Date: Fri, Jan 28 2011 3:13 pm
From: Stroonz

On Jan 28, 10:43 am, Fred <nob...@home.com> wrote:
> Stroonz <str00...@aol.com> wrote in news:50ee54ab-1903-4898-adcd-
> 0030de67d...@u14g2000vbg.googlegroups.com:
>
> > Can't find one anywhere, maybe not available.  Any help appreciated.
>
> You need to learn aboutwww.google.com
>
> I put in STK795 data sheet and got over 16,000 hits.  Take your pick.

And that helps me how? The STK795 series includes everything from
voltage regulators to IPMs. Anyone with knowledge of semiconductors
and hybrid ICs would know there are fundamental differences between
chopper regulators, amplifiers, IPMs, etc. I can't just "take my
pick". What I need is a datasheet for the STK795-820. The 821 is
functionally similar.

== 2 of 3 ==
Date: Fri, Jan 28 2011 4:44 pm
From: Meat Plow

On Fri, 28 Jan 2011 15:13:12 -0800, Stroonz wrote:

> On Jan 28, 10:43 am, Fred <nob...@home.com> wrote:
>> Stroonz <str00...@aol.com> wrote in news:50ee54ab-1903-4898-adcd-
>> 0030de67d...@u14g2000vbg.googlegroups.com:
>>
>> > Can't find one anywhere, maybe not available.  Any help appreciated.
>>
>> You need to learn aboutwww.google.com
>>
>> I put in STK795 data sheet and got over 16,000 hits.  Take your pick.
>
> And that helps me how? The STK795 series includes everything from
> voltage regulators to IPMs. Anyone with knowledge of semiconductors
> and hybrid ICs would know there are fundamental differences between
> chopper regulators, amplifiers, IPMs, etc. I can't just "take my pick".
> What I need is a datasheet for the STK795-820. The 821 is functionally
> similar.

Just what did you need the data sheet for? The YPPD-J018C is the LG
version for their YSUS amp.

--
Live Fast, Die Young and Leave a Pretty Corpse

== 3 of 3 ==
Date: Fri, Jan 28 2011 6:32 pm
From: "Dave M"

Stroonz wrote:
> On Jan 28, 10:43 am, Fred <nob...@home.com> wrote:
>> Stroonz <str00...@aol.com> wrote in news:50ee54ab-1903-4898-adcd-
>> 0030de67d...@u14g2000vbg.googlegroups.com:
>>
>>> Can't find one anywhere, maybe not available. Any help appreciated.
>>
>> You need to learn aboutwww.google.com
>>
>> I put in STK795 data sheet and got over 16,000 hits. Take your pick.
>
> And that helps me how? The STK795 series includes everything from
> voltage regulators to IPMs. Anyone with knowledge of semiconductors
> and hybrid ICs would know there are fundamental differences between
> chopper regulators, amplifiers, IPMs, etc. I can't just "take my
> pick". What I need is a datasheet for the STK795-820. The 821 is
> functionally similar.

Ummm... I think you missed the point. If you ask Google for exactly what
you want, chances it will give it to you. Google for

"STK795-820" datasheeet

and you'll find it very quickly. Be sure to enclose the "STK795-820" within
quotes, because the Google search engine interprets the dash as an exclusion
term. That is, a dash in front of a word or character string will exclude
that string from the search.

Click on Advanced Search (on the Google search page) and your searches will
be much more productive.
--
David
dgminala at mediacombb dot net

==============================================================================
TOPIC: DTV sound synch
http://groups.google.com/group/sci.electronics.repair/t/2896d12048fef530?hl=en
==============================================================================

== 1 of 2 ==
Date: Fri, Jan 28 2011 8:00 pm
From: David Nebenzahl

Question is about DTV sound synchronization in the United States (the
only DTV I have any experience of). Seems to me that since it replaced
analog, the synchronization of sound to picture is, at best, variable,
and sometimes it's absolutely piss-poor.

Watching some programming, like a classical music performance where one
can see string players' bows moving, sometimes the sound is so far off
as to be quite irritating, seemingly as much as half a second or so.

I don't know enough about DTV to say why this would be so, and whether
the problem is with the station originating the broadcast or somewhere
else along the line. (I'm guessing this problem doesn't occur at the
receiver end.) Anyone else notice this?

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

== 2 of 2 ==
Date: Sat, Jan 29 2011 12:39 am
From: "N_Cook"

David Nebenzahl <nobody@but.us.chickens> wrote in message
news:4d439097$0$23162$822641b3@news.adtechcomputers.com...
> Question is about DTV sound synchronization in the United States (the
> only DTV I have any experience of). Seems to me that since it replaced
> analog, the synchronization of sound to picture is, at best, variable,
> and sometimes it's absolutely piss-poor.
>
> Watching some programming, like a classical music performance where one
> can see string players' bows moving, sometimes the sound is so far off
> as to be quite irritating, seemingly as much as half a second or so.
>
> I don't know enough about DTV to say why this would be so, and whether
> the problem is with the station originating the broadcast or somewhere
> else along the line. (I'm guessing this problem doesn't occur at the
> receiver end.) Anyone else notice this?
>
>
> --
> Comment on quaint Usenet customs, from Usenet:
>
> To me, the *plonk...* reminds me of the old man at the public hearing
> who stands to make his point, then removes his hearing aid as a sign
> that he is not going to hear any rebuttals.

Even on , supposed, live feeds , often lack of sync in the UK
You mention classical music. I cannot listen to proper music on any of the
UK freeview channels because of some sort of overload distortion. This is
same on 2 makes of set-top box , is it just Rowridge, IoW, transmissions/
local multipath problem to me or do others find this issue in the UK? Is
there a name for this distortion ? full orchestra with the brakes on is fine
but go forte and clipping sort of compression distortion - if only they
still had test-cards with pilot tone these days, so I could scope.
And also related, no time signals these days, no seconds of time mentioned
anywhere on digital.

==============================================================================
TOPIC: Yamaha EMX5016 mixer amp from 2006
http://groups.google.com/group/sci.electronics.repair/t/bc288deddd9278ea?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, Jan 29 2011 12:26 am
From: "N_Cook"

When I reassemble it I'll double scope the outputs, but anyone know if one
amp output , to the output board that is, is inverted relative to the other
somewhere.?
For the 1/4 inch outputs , violet,A, L ch is normal sleeve ground but yellow
ch is tip ground. Likewise the paralleled speakon outputs , inner and outer
contacts are swapped between channels.
BTW to work on this amp in 2 halves , you need to fudge a chassis ground
interconnect

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