• Check out the Annual AK Secret Santa exchange Program, signup before November 23rd in the AK Charities & Christmas forum!

Another question regarding XLR vs. RCA...

reickmey

reickmey

Active Member
So, this cable goes between my AMP and my DAC.

I'm having a difficult time A-B testing my RCA 1m Kimber Hero vs. my XLR 1m Audioquest Colorado due to the XLR cables being noticeably louder than the RCA cables.

So these are my questions:

Why is the XLR cable set louder than the RCA cables?..I've heard about a three DB increase due to the fact there are two signals being fed with the XLR cables but still don't fully understand how that translates to three DB.

and...

If the DB increase is free for the XLR cables then wouldn't that be the best choice since it allows the amp to work with less effort to provide the same volume?

If there are any questions about my system see my signature.

Any help would be appreciated.

Thanks,

~Ryan
 
Last edited:
Register to hide this ad
If you tried to run an RCA cable @ the signal level of an XLR it may well end up being noisy as he!!.

The whole reason for XLR has to do with significantly lowering the noise floor so the signal is "cleaner" than you can get with traditional RCA cables.

That is especially important with regards to longer cable runs where interference becomes far more likely.

The "hotter" XLR signal is that way due to how XLR sends signals to the given device so it wont be affected by any outside influences.
That's despite the distances between those devices.

Just remember that XLR also requires appropriate electronics at both ends of the signal chain to get the full effect of using that hardware,and those additional electronics typically costs more $$$,thus why consumer gear typically uses unbalanced (RCA -or- 1/4") interconnects.

That +3db you're seeing represents the attendant increase in dynamic range,and thus it's a means to ensure maximum signal integrity.

Comparing RCA & XLR is akin to comparing apples & oranges,so it's not really a surprise that you are having trouble a/b'ing them.

FWIW

Bret P.
 
Last edited:
Unless you're really pushing levels or going long distances with your cables, RCA is fine. Sound quality - wise there is zero difference. For the same total volume level, the amp being pushed the same. The difference is maybe your DAC's output won't be pushed as hard but it really shouldn't make much difference.
 
Your amp isn't working any harder in either case. If you reach a certain level at a lower number than the other it's working just as hard as it would if the level number was higher for the same level. It can only put out so much power no matter where the input level is set.
 
Most likely, the difference between XLR and RCA is 6dB, not 3dB. This is because the magnitude of the audio voltage signal is now doubled. Just from the sounds of you situation, I'd say the CD player is to "blame" for this. It would appear they chose to equate 0dBFS to the typical 2VRMS level for the RCA connection and opted to make the XLR a 4VRMS @ 0dBFS. They could have chosen to make them the same, but it's easier to double the XLR voltage.

The greater voltage on the XLR doesn't come for free. It has the added cost of an extra transformer, or addition active electronics. Plus, the added expense of non-cheap XLR connectors. The amp works the exact same amount for a given output, no matter what the driving voltage is.
 
Last edited:
I would'nt say that there is'nt a difference SQ wise,as XLR should almost always have better SQ vs. unbalanced audio due to it's attendant reduction of noise.

But that of course assumes the gear being used can take advantage of such.

Typically an amp that has XLR inputs will almost always have some sorta input signal attenuation to control the input level gain for just such a reason.

And preamps w/XLR outs will need additional hardware inside as well (transformers/XLR drivers and such).

As an example: I went ahead and used XLR between my NAD 106 preamp and EV-7100 amp for just that reason,and that's a short run of cable (3" or so),but those two pieces of gear are designed to be used that way,and the XLR outs/ins were already there,so there was no reason not to use it,so in that situation it's really a no brainer.

A typical line level signal usually is'nt that powerful a signal,especially in most consumer oriented gear,so that side of things (between a source & the preamp) typically does'nt matter nearly as much as it would on the other side of things (between the preamp & power amp),the most common exception to that is some higher end CD players as they are often equipped with balanced outs too.

But there should always be an improvement in areas of increased dynamic range,reducing noise and a lowering of the overall noise floor with XLR.
So that'll almost always = better SQ.

Of course as usual YMMV....

Bret P.
 
Last edited:
IMO, it's more like a deal with the amp.

As the DAC has both balanced and unbalanced outputs, it's typical the balanced output will have 2x voltage of the unbalanced swing since there arw two signals at play (normal and inverted) rather than one. This is why the balanced output is typically 6dB hotter (2x voltage swing).

In the amp that should be taken into account so the gain of the unbalanced inputs and balanced inputs are the same. Often, though, it's not so the balanced connections are louder relative to unbalanced at any given point of.volume adjustment.

As has been already pointed out, the amp is not more powerful or working harder, it just takes more or less volume adjustment to work the same.

As well, in most cases, balanced inputs and outputs are just additional circuity tacked onto unbalanced guts. There is a lot of opinion simpler is better unless you have a noise ingress problem that can be mitigated by using balanced interconnects.
 
The way a balance connection was explained to me is:
The same signal is generated on both +/- contacts of the XLR, but out of phase. At the receiving end the opposite phase is flipped so both are in-phase giving the +3db of gain. Also any noise is now out of phase between the + and - lines and cancels.
 
So when I increase the volume on my amp is that forcing the amp to consume more power?..I assumed it was. It just makes sense to me that the less power that is needed to drive my speakers the better...and if XLR then increases the amplitude of the signal without having the volume increased on the amp then I'm getting that for free from the DAC...no?

...but from everyones replays it seems i'm missing something.
 
At that volume level when you switch from RCA to XLR, your amp is consuming more power. However, if you were to turn it down the 6 dB to compensate, the amp would be using exactly the same power. The XLR gives your dac/preamp additional gain that it can output versus RCA.
 
Nightwisher said:
At that volume level when you switch from RCA to XLR, your amp is consuming more power. However, if you were to turn it down the 6 dB to compensate, the amp would be using exactly the same power. The XLR gives your preamp additional gain that it can output versus RCA.
Click to expand...

Phew, ok thats what I thought...so we get more gain with XLRs...could that mean we would have slightly more clarity at higher volumes with XLRs compared to RCAs?..because of that slight gain bump?
 
Nightwisher said:
At that volume level when you switch from RCA to XLR, your amp is consuming more power. However, if you were to turn it down the 6 dB to compensate, the amp would be using exactly the same power. The XLR gives your dac/preamp additional gain that it can output versus RCA.
Click to expand...

It doesn't add anything in the form of gain. Unbalancing attenuates signal strength.
The balanced cable has a dynamic range capability of 6dB over/higher than an unbalanced cable (example of unbalanced: RCA).
In recording, I'll often get a signal that is a bit too hot for an unbalanced input, especially in the days of tape media (either analog tape, or DAT). This is fairly common from a mixing console output. To counter that I built "unbalancing" adaptors for the XLR cable. They are essentially an XLR->RCA connector cable where you leave XLR pin-2 open, and wire to XLR pin-1&3
This attenuates the balanced signal by about 6dB, and gets the signal back to a level that an unbalanced input can handle.
 
mfrench said:
It doesn't add anything in the form of gain. Unbalancing attenuates signal strength.
The balanced cable has a dynamic range capability of 6dB over/higher than an unbalanced cable (example of unbalanced: RCA).
In recording, I'll often get a signal that is a bit too hot for an unbalanced input, especially in the days of tape media (either analog tape, or DAT). This is fairly common from a mixing console output. To counter that I built "unbalancing" adaptors for the XLR cable. They are essentially an XLR->RCA connector cable where you leave XLR pin-2 open, and wire to XLR pin-1&3
This attenuates the balanced signal by about 6dB, and gets the signal back to a level that an unbalanced input can handle.
Click to expand...

Can you explain how attenuation applies?..I don't know much about it except what wikipedia gives:

https://en.wikipedia.org/wiki/Attenuation
 
It doesn't really attenuate.

A symmetrical driver will send the signal, let's call it 3V, on one line and the inverse on the other line, -3V. The differential receiver output is the difference between the two signals: 6V. That's where your +6dB comes from, or in the context of @mfrench's scenario, where the -6dB comes from.

The signal isn't hotter for 'noise immunity', it's hotter as a consequence of being made symmetrical. The noise immunity of a balanced connection is simply common mode rejection.
 
So we get more gain with XLRs...could that mean we would have slightly more clarity at higher volumes with XLRs compared to RCAs?..because of that slight gain bump that we get from the DAC?
 
JP said:
It doesn't really attenuate.

A symmetrical driver will send the signal, let's call it 3V, on one line and the inverse on the other line, -3V. The differential receiver output is the difference between the two signals: 6V. That's where your +6dB comes from, or in the context of mfrench's scenario, where the -6dB comes from.

The signal isn't hotter for 'noise immunity', it's hotter as a consequence of being made symmetrical. The noise immunity of a balanced connection is simply common mode rejection.
Click to expand...

What would you call it, if not attenuate?
I've used/heard the term extensively in the field recording world when speaking of this very point. There was a period where the more compact "prosumer" recorders were only capable of input values of 20dBu (and this is still a reality), but the output from outboard preamps was more along the line of 26dBu. By utilizing the unbalanced interface, we stood a better chance of not brickwalling the input to the recorder by reducing the output value to be a closer match to the input value of the recorder.

Other options:
> truncates (might be a bit more accurate)
> reduces
 
reickmey said:
I feel my answer still isnt really being answered...anyone?
Click to expand...

I hesitate to answer because I get the impression you are already convinced it is/does.

But, my opinion is no. Not no inasmuch as you may hear a difference, but I don't believe the difference in gain/level inherently creates more clarity at higher volume.

Basically all it does is change where the volume control must be placed for any given output. Now, if the circuit is such that changing resistance due to volume control position influences the circuit enough outside of the basic increase/decrease in volume, that's a different matter...but not the cause from higher or lower input signal level.
 
Last edited:
mfrench said:
What would you call it, if not attenuate?
Click to expand...

I was speaking in a stricter sense. As a generally accepted and understood term for what the overall affect is, I suppose attenuate is as good as any. I don't have a better one for you. From an electrical perspective when you say attenuate I'm looking for a resistive divider, active device, etc. that is reducing the signal. Unbalancing the signal in that sense is quite different.

reickmey said:
I feel my answer still isnt really being answered...anyone?
Click to expand...

All things being equal, no. As you have to reduce the volume due to having a hotter signal with XLR, chances are you're doing that by ear. We perceive small differences in loudness as increased dynamics, or clarity. There's also cognitive bias to consider.
 
@JP
Thanks! I wasn't trying to corner you for an answer. But I was genuinely confused, and not sure what else to call it.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom