Something crazy i read in another forum

[socketman]

At another forum I frequent someone stated something I believe not to be true but I am not sure just how to refute it. Maybe my understanding of pre/pro's and amps is misguided but from what I see with my XMC-1 and XPA 5 the balanced out has a higher Voltage output than the unbalanced. On the Xpa 5 the input impedance is higher on the Balanced than the unbalanced which basically makes them drive the amp in a similar fashion. Below is the statement made that I am having trouble getting my mind around. Amplifier gain is fixed by the designer is it not?  29db gain is pretty standard in consumer gear. Can someone clarify for me pls.


And BTW, going from RCA to XLR doesn't reduce the sound quality, it just reduces the gain by about -10db

Now if you were to use adapters from unbalanced outs on the pre/pro to balanced on the amp that may reduce the overall output of the amp.

[Gary Cook]

That's one confused poster. The amp's gain is the amp's gain, it can be varied by design, but not commonly so. Balanced connections (eg; XLR's) run 2 out of phase signals, in the case of an XMC-1 that's +5.5 volts and -5.5 volts at maximum volume, hence 11 volts. Whilst the unbalanced (eg; RCA) output is 5.5 volts. With differential circuitry this commonly results in around 6db increase in loudness when using a power amplifier's balanced inputs compared to its unbalanced inputs. Same gain, just more volts in = more watts out. In the case of an MXC-1 a fully balanced signal (balanced input and balanced output) results in a 9 db improvement in the S/N ratio.

Not sure where the 10db comes from, maybe ask the poster.

Cheers
Gary

[socketman]

Thanks gary, that's how I understood it . I figured out what he was really saying , he was indeed speaking about using an rca to xlr adapter which would cut the input to the amplifier by half and in his case it resulted in a 10db loss in total output from the amp. I really think people sometimes type faster than their brain thinks and erroneous statements are the result which then goes around the internet and becomes fact somehow . LOL

[Gary Cook]

Oct 23, 2016 21:58:27 GMT -5 socketman said:

Thanks gary, that's how I understood it . I figured out what he was really saying , he was indeed speaking about using an rca to xlr adapter which would cut the input to the amplifier by half and in his case it resulted in a 10db loss in total output from the amp. I really think people sometimes type faster than their brain thinks and erroneous statements are the result which then goes around the internet and becomes fact somehow . LOL

Based on my experience 10 db is a bit much, I could believe 6'ish. But even then it's at the same input volume setting, simply turn up the volume and get the db's back. It would need around 0.25 of a volt more input, hardly a big deal.

Cheers
Gary

[KeithL]

I think you'll find that it's a case of someone "reading more into it than belongs there".

The reality is that, on any given piece of equipment, the balanced input and unbalanced input, or the balanced output and unbalanced output, often go through slightly different circuit paths.
(Generally, depending on the internal architecture of the specific equipment involved, one of those will be "direct" and the other will "be going through a conversion".)
This means that, on a specific piece of equipment, one or the other may be slightly better; however, unless the designer is pretty bad, they should be very close.
However, it doesn't rule out the possibility that the balanced or unbalanced input or output on a specific component may sound noticeably better or worse.

The level misunderstanding comes from the fact that a balanced connection carries two equal and opposite versions of the signal.
This might mathematically suggest that, when you add the two signals, the original signal level would be doubled.
However, in many designs, the effective gain is halved by design .... so the end result is the same output level.
(It really just depends on how the equipment was designed.)

Likewise, if you connect an unbalanced output into a balanced input, whether the level will be different will depend on how it's wired.
And some converters may drop the level (and a few with transformers in them may even boost it).

And, finally, most "pro" equipment uses balanced connections; and most pro equipment ALSO uses a higher signal level.
(However, the balanced connections on consumer equipment are usually NOT using the higher "pro level", and not all pro equipment does either.)

In general, it shouldn't actually matter much, as long as you have enough level to reach full output......

[Kent]

My interconnect from my UMC-1 to my XPR-1's used to be RCA-RCA. I switched the amp end to a Neutrik XLR (just to experiment). Volume is the same but I find it slightly more transparent sounding. However, now my meters won't dance no matter how loud I play music but before when it was RCA-RCA it did? It's not something I'm upset about but just wondered why?

Keith can you chime in about this please?

[leonski]

just like most everything else in audio, 'it depends'.

The rule of thumb is the difference between balanced and single ended is 6db. Internal design can alter this, but Generally, the 6db difference holds.

Now, the 'depends' part. In a NATIVE BALANCED design, the conversion to single ended MAY have sonic consequences. or maybe not. And the reverse is also true.

My CD player, a CA840, was balanced and into REAL balanced inputs of my integrated, a PSAudio, it was better than single ended. Even using upscale single ended wiring. My balanced cable was MOGAMI.