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Author Topic: Pseudo balanced outputs?  (Read 26994 times)

Irving A. Hammond Jr.

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Re: Pseudo balanced outputs?
« Reply #60 on: March 06, 2012, 02:25:30 pm »

I've found this application paper on the interconnection of
balanced and unbalanced lines on Jensen's site.

http://www.jensen-transformers.com/an/an003.pdf

On Page 2 it describes a pseudo balanced as just the shield and ring tied together not impedance balanced.

They also describe impedance balanced output vs typical "pro" balanced outputs.
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John Roberts {JR}

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Re: Pseudo balanced outputs?
« Reply #61 on: March 06, 2012, 02:56:49 pm »

I've found this application paper on the interconnection of
balanced and unbalanced lines on Jensen's site.

http://www.jensen-transformers.com/an/an003.pdf

On Page 2 it describes a pseudo balanced as just the shield and ring tied together not impedance balanced.

They also describe impedance balanced output vs typical "pro" balanced outputs.

So why tell us? Tell them their almost 20 year old application note to pimp transformers is using that vague term even more vaguely than most.  Bill Whitlock is a solid citizen, and even they say it is  "sometimes called pseudo balanced"  in their hypothetical before example, to make their after with transformer improvement look even better.

On page three they show an actual impedance balanced termination (2.4), but neglect to measure that compared to their expensive transformer version.  8).

I do not consider "pseudo-balanced" a concise technical term with clear meaning, but I've already said that. Your alternate example, that is in conflict with the Rane glossary, just reinforces my earlier stated judgement.

I do consider "impedance balanced" harder to misconstrue, and to have some actual literal meaning.

You guys can call it whatever you want...I am loosing interest in this dialog.

JR

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Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Andy_Leviss

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Re: Pseudo balanced outputs?
« Reply #62 on: March 21, 2012, 02:24:30 pm »

So why tell us? Tell them their almost 20 year old application note to pimp transformers is using that vague term even more vaguely than most.  Bill Whitlock is a solid citizen, and even they say it is  "sometimes called pseudo balanced"  in their hypothetical before example, to make their after with transformer improvement look even better.

Er, what? Bill, and his presentation notes on the Jensen sites, are where I learned about impedance balancing. Further, Bill himself is emphatic to point out that signal symmetry has NOTHING to do with CMNR. NOTHING. If the impedances are matched, the noise will be induced equally in both lines. The differential input will flip pin 3, the noise cancels out.

The ONLY benefit symmetrical signals give you is an additional 6 dB. But this does not make it not balanced, and does NOT affect CMNR.

If I really need to, I'll dig out the algebraic proof I did of it the last time I got into this argument with somebody. But I'd rather not :-)

--A
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Andy Leviss
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Tim McCulloch

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Re: Pseudo balanced outputs?
« Reply #63 on: March 21, 2012, 03:03:33 pm »

It used to bother me too, but if you check the OED, it lists "Podium" as the second definition of "Lectern". I will defer to the OED.

Mac

At the PAC we recently had a customer insist on getting a "podium" on the stage for a presenter.  The carpenter went to the basement and brought up a conductor's podium.  The customer said "that's not what I asked for."  The carpenter brought up every podium in the store room and asked the customer to pick the one she liked.  She sputtered about the carpenter's incompetence and went so far as to call the PAC's event coordinator to complain.

The event coordinator arrived in the hall and said "well, you asked for podium, you have a selection... would you like us to paint one a different color or drape it?"  She finally said "no, like a church pulpit."  "Oh, a LECTERN!  What color and height would you like?"
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

John Roberts {JR}

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Re: Pseudo balanced outputs?
« Reply #64 on: March 21, 2012, 03:29:52 pm »

Er, what? Bill, and his presentation notes on the Jensen sites, are where I learned about impedance balancing. Further, Bill himself is emphatic to point out that signal symmetry has NOTHING to do with CMNR. NOTHING. If the impedances are matched, the noise will be induced equally in both lines. The differential input will flip pin 3, the noise cancels out.

The ONLY benefit symmetrical signals give you is an additional 6 dB. But this does not make it not balanced, and does NOT affect CMNR.

If I really need to, I'll dig out the algebraic proof I did of it the last time I got into this argument with somebody. But I'd rather not :-)

--A

I see your "what?" and reply HUH? Since apparently I haven't been completely clear, my primary quibble is with the lack of clarity and meaning in the term "pseudo" -balanced.

Quote from:  merriam webster
Pseudo: being apparently rather than actually as stated : sham, spurious

"Impedance balanced" actually means something specific and is effectively balanced for interfaces, not a sham or "apparently" it's actually a "balanced termination". 

I only quoted from Bill's old app note after somebody else did first to make their point (for argumentative symmetry).

FWIW, and this is way too much information, there are subtle esoteric benefits to symmetrical signal feeds, besides the + 6dB signal increase available from same voltage power supplies, but they are subtle and esoteric, so not worth the veer here now.

This thread is evidence that there is already too much confusion surrounding these interfaces, I don't need to add to it, more than I apparently already have.

JR
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Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

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Re: Pseudo balanced outputs?
« Reply #64 on: March 21, 2012, 03:29:52 pm »


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