ruffrecords

Increase in use of 'impedance balanced' outputs
« on: October 12, 2020, 05:43:14 PM »
I am beginning to detect a significant increase in the number of products whose outputs are impedance balanced. The reasons are obvious - it is a simple cheap way to obtain most of the benefits of balancing. This seems to happen mostly on multi-channel 'interfaces' designed to be attached to a PC. I have noticed some discussion of Slutz about whether or not this is a con (or just a lack of understanding). I have also corresponded with several people who have contacted manufacturers about the balanced outputs of their products who have been told without exception that they are impedance balanced ( the last one a few days ago).

So, are we about to see the end of differential balanced outs?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


JohnRoberts

Re: Increase in use of 'impedance balanced' outputs
« Reply #1 on: October 12, 2020, 06:00:25 PM »
I am beginning to detect a significant increase in the number of products whose outputs are impedance balanced. The reasons are obvious - it is a simple cheap way to obtain most of the benefits of balancing. This seems to happen mostly on multi-channel 'interfaces' designed to be attached to a PC. I have noticed some discussion of Slutz about whether or not this is a con (or just a lack of understanding). I have also corresponded with several people who have contacted manufacturers about the balanced outputs of their products who have been told without exception that they are impedance balanced ( the last one a few days ago).

So, are we about to see the end of differential balanced outs?

Cheers

Ian
This is not really recent... Mackie, remember them? pioneered the use of "impedance" balanced outputs last century while marketing them as "balanced"  ::) with massive ad campaigns.

This is an old topic and well inspected.  IMO impedance balanced is as good as active balanced for 99.9% of modern applications and only a tiny fraction of the cost.

I approve that cleverness (Greg got a lot of marketing benefit from those $0.02 resistors) but I didn't appreciate the loss of market share (from all the advertising), while few consumers had a clue about what was what.

There are multiple active balanced output driver chip sets so those will still win premium SKU design-ins because of their +6dB hotter output level... that "looks" good on data sheets.

Consumers will still believe that more is better...   ::)

JR

Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

abbey road d enfer

Re: Increase in use of 'impedance balanced' outputs
« Reply #2 on: October 13, 2020, 05:22:38 AM »
In a world of 3.3V ADC, who needs +26 dBu outputs?
In terms of signal integrity, a simple opamp will beat a CCOS anytime.
I respect very much THAT's developments though.
Modern (digital) equipment is designed to operate differently than the legacy analog, which offered its better performance compromise at about 15-20dB below its max.
Digital stuff is designed to operate closer to its maximum, since in the digital realm, more used bits is better; the surrounding analog stuff is optimized for operating at this elevated level.
Of course, the compromise is different for hybrid (old with new) set-ups.

An advantage of CCOS vs. Z-balanced is that connection to an unbalanced receiver provides noise rejection.
The circuit used by Soundcraft (Doug Self's?) does it too.
« Last Edit: October 13, 2020, 05:30:52 AM by abbey road d enfer »
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

john12ax7

Re: Increase in use of 'impedance balanced' outputs
« Reply #3 on: October 13, 2020, 02:46:47 PM »
I generally prefer impedance balanced when not using a transformer.

squarewave

Re: Increase in use of 'impedance balanced' outputs
« Reply #4 on: October 13, 2020, 03:22:11 PM »
You can't assume outputs are going to ADCs. There's lots of outboard gear that might be in the path that needs a higher level for noise performance and / or to provoke it's mojo like compressors and such. But -6dB is not a problem. Impedance balanced outputs are dandy for just about anything except maybe driving really long lines.

Michael Tibes

Re: Increase in use of 'impedance balanced' outputs
« Reply #5 on: October 17, 2020, 05:37:10 AM »
It took me a while to understand it's pros and (in my opinion) lack of cons for my own designs, now I'm a fan ;-)

Michael

EmRR

Re: Increase in use of 'impedance balanced' outputs
« Reply #6 on: October 19, 2020, 01:33:32 AM »
As good a (recent) place as any:

Reading ‘The Emergence of Broadcasting in Britain’ I see the date 17 May 1923 when engineers desperate to make radio distribution through telephone lines without crosstalk, first tried balancing the lines to perfect success.   

The funny bit is the original power calculations suggested they needed to drive the lines with 40W. In the end that was dropped to 1mW, still unsatisfactory, before they tried balanced lines. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

Re: Increase in use of 'impedance balanced' outputs
« Reply #7 on: October 19, 2020, 09:22:26 AM »
You can't assume outputs are going to ADCs. There's lots of outboard gear that might be in the path that needs a higher level for noise performance and / or to provoke it's mojo like compressors and such. But -6dB is not a problem. Impedance balanced outputs are dandy for just about anything except maybe driving really long lines.
Agreed, however in the case of mic pre's, a lot of people are going straight to ADC.


 

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