My new arrival preamp/DAC has both outputs
• RCA Output Level: 2.0V RMS @ 0dBFS
• XLR Balanced Output Level: 4.0V RMS @ 0dBFS
Besides the higher output voltage would I realize any sound quality improvements by going XLR > RCA in the form of an adapter cable, then into unbalance inputs on my power amp?
Or would the step put things back on a level playing field? I just parted ways with a power amp that has both inputs. My next move was welcome yet unexpected.
• RCA Output Level: 2.0V RMS @ 0dBFS
• XLR Balanced Output Level: 4.0V RMS @ 0dBFS
Besides the higher output voltage would I realize any sound quality improvements by going XLR > RCA in the form of an adapter cable, then into unbalance inputs on my power amp?
Or would the step put things back on a level playing field? I just parted ways with a power amp that has both inputs. My next move was welcome yet unexpected.
Balanced line is widely used for low voltage (millivolts) of microphone signal that is sent down a long cable. The balanced input sees the + and - signals (pins 2 and 3 of the XLR) and can ignore any noise that is of the same phasing on the lines. For home use with a short run of cable and into an unbalanced input, I feel is a waste of effort for practically no gain.
For unbalanced inputs as said no point. Having balanced INPUTS I do feel is an advantage even in a domestic environment just due to the huge number of potential interference sources in the modern house. Its belt and braces but at least it has a measurable (if not audible) improvement.
Keep in mind that the balanced inputs and outputs are adapters. The equipment is normally single-ended inside. I would only go to a balanced connection if there was a problem that could be solved going that route.
There is a vast difference between a balanced external interconnect system and an internal symmetrical (balanced) circuit.
Your numbers show that the DAC RCA signal is the same as you would get from the XLR through an XLR > RCA adapter, so no gain there.
The choice is to use a) the original RCA at the DAC and a SE cable to the power amp, or b) the BAL from the DAC through a BAL cable and an adapter at the power amp.
In theory, doing the conversion at the power amp would give you additional noise immunity due to keeping things balanced right up to the power amp, but that will only matter in an electronically dirty environment. The proof of the pudding an all that.
Jan
Hi Kevin,
The vast majority of equipment is single-ended internally. There are very few true balanced systems in the audio world compared to the single-ended equipment.
One reason for this is that a true balanced system throughout is double the circuitry that would be used in a single-ended design. That is both expensive, and power hungry. Plus, the matching required between the phases needs to be bang on, as well as phase shifts or you will lose the primary benefit of the balanced system. That would be common mode rejection. Your best bang for the buck takes place when a single-ended system has the balanced circuitry added to the circuit extremes - the signal input and signal output. Therefore, most equipment that does have balanced connections built in are actually adapters that fit to the single ended inputs and outputs.
Hi Jan,
Completely agree with you.
-Chris
The vast majority of equipment is single-ended internally. There are very few true balanced systems in the audio world compared to the single-ended equipment.
One reason for this is that a true balanced system throughout is double the circuitry that would be used in a single-ended design. That is both expensive, and power hungry. Plus, the matching required between the phases needs to be bang on, as well as phase shifts or you will lose the primary benefit of the balanced system. That would be common mode rejection. Your best bang for the buck takes place when a single-ended system has the balanced circuitry added to the circuit extremes - the signal input and signal output. Therefore, most equipment that does have balanced connections built in are actually adapters that fit to the single ended inputs and outputs.
Hi Jan,
Completely agree with you.
-Chris
My PA amp has both balanced XLR input, with both op amp inputs hooked up, and 1/4 phone unbalanced with one op amp input grounded.
So I made a 7' XLR cable from my RCA output mixer.
There was no improvement in sound quality over RCA cable with adapter to 1/4 phone plug. I don't have any digital interferance sources in the music room but I do have a lamp dimmer. At 1.5 Vpp levels on the speaker the PA amp sounds remarkably like a totally unbalanced 1966 design amp (updated output transistor idle current circuit) with capacitors on input and speaker.
If your amp has balanced input, try the experiment; buy both cables. Try it both ways. It is diyaudio after all. Report back here.
So I made a 7' XLR cable from my RCA output mixer.
There was no improvement in sound quality over RCA cable with adapter to 1/4 phone plug. I don't have any digital interferance sources in the music room but I do have a lamp dimmer. At 1.5 Vpp levels on the speaker the PA amp sounds remarkably like a totally unbalanced 1966 design amp (updated output transistor idle current circuit) with capacitors on input and speaker.
If your amp has balanced input, try the experiment; buy both cables. Try it both ways. It is diyaudio after all. Report back here.
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Hi Chris,
Yes I agree that balanced internal circuits are unnecessary. But when we get into the harsh cruel external world of noise & interference, a balanced interconnect system is the way to go.
Yes I agree that balanced internal circuits are unnecessary. But when we get into the harsh cruel external world of noise & interference, a balanced interconnect system is the way to go.
... and the key point for noise immunity with balanced connections is balancing the impedances (including parasitics). Balancing the signal itself ("splitting the phases") isn't.
Hi Kevin,
Agreed. In sub-optimal environments a balanced connection can solve a lot of problems. Having said that, there was one jingle studio that had problems that were solved by putting them on a single-ended system. It didn't help that some of their gear was that -10 dBv / +4 dBm junk. So believe it or not, equipment across two floors worked better in that one instance as single ended.
Yes, I was surprised too.
-Chris
Agreed. In sub-optimal environments a balanced connection can solve a lot of problems. Having said that, there was one jingle studio that had problems that were solved by putting them on a single-ended system. It didn't help that some of their gear was that -10 dBv / +4 dBm junk. So believe it or not, equipment across two floors worked better in that one instance as single ended.
Yes, I was surprised too.
-Chris
Unbalanced voltage seems adequate. The digital volume steps increments of 1db maxing out at 90 which is more than plenty for current amp/speaker combination. I haven't had to push it past 20 for most recordings.
I do have a bit of an interference issue obvious on mute, even though its subtle. I've tried five different interconnects. I think I will try the suggested balanced cables to just before amplifier and see if it clears up. If only for this I'll find it worth doing.
I do have a bit of an interference issue obvious on mute, even though its subtle. I've tried five different interconnects. I think I will try the suggested balanced cables to just before amplifier and see if it clears up. If only for this I'll find it worth doing.
Hi SS4927,
The two most critical places in a sound system for cables are the phono, and between the preamplifier and the amplifier. Some signals into the amplifier are down to phono cartridge level and can be audible - like your interference issue on mute. The balanced cables may do the trick for you.
-Chris
The two most critical places in a sound system for cables are the phono, and between the preamplifier and the amplifier. Some signals into the amplifier are down to phono cartridge level and can be audible - like your interference issue on mute. The balanced cables may do the trick for you.
-Chris
There is absolutely no benefit of using an XLR-to-RCA adapter cable for sonic benefit. Internally, the negative polarity wire of the XLR is just shunted to ground anyways (with possibly a resistor).
That being said, yes, most of the audio equipment on the market is NOT fully balanced internally (what I like to call fully differential), even though the audio device may have balanced XLR outputs.
There is still a benefit of using balanced XLR cable in these situations. In these situation, the audio signal is only sent from the preamp on the positive wire of the XLR cable. In the receiving device (such as an amp), the input circuit sees a positive voltage on the normal XLR signal wire (when there is a positive waveform). The input circuit essentially routes that same positive charge back on the negative polarity wire (where the preamp sees it as a negative waveform, or opposing polarity). This means that the two signal wires on the XLR cable are seeing opposite voltages (i.e. the current is flowing opposing directions). On the preamp side, the negative polarity wire is typically shunted to ground through a resistor. I still consider this a balanced audio signal (just not fully differential).
There is a hysteresis type of affect between the opposing voltage of these two wires (since they are so close) that helps stabilize the main signal wire and reduces distortion and helps with natural shielding. This will, in turn, affect the sound quality overall.
In cases where there is a true balanced differential circuit in the preamp, the sound quality will be even better and actually more controlled because the positive and negative polarity signals are being -generated- by the source instead of just having the negative signal echoed back from the amplifier using an opamp type circuit.
There --MAY-- be an improvement in your situation when using an XLR cable if you use something like a Jensen PC-2XR transformer on the amp side. Then use a VERY short RCA cable to connect between the Jensen and the amp (like 6" or so). This keeps the single-ended RCA wire very short and you have the longer XLR cable being truly balanced.
PC-2XR | Jensen Transformers
That being said, yes, most of the audio equipment on the market is NOT fully balanced internally (what I like to call fully differential), even though the audio device may have balanced XLR outputs.
There is still a benefit of using balanced XLR cable in these situations. In these situation, the audio signal is only sent from the preamp on the positive wire of the XLR cable. In the receiving device (such as an amp), the input circuit sees a positive voltage on the normal XLR signal wire (when there is a positive waveform). The input circuit essentially routes that same positive charge back on the negative polarity wire (where the preamp sees it as a negative waveform, or opposing polarity). This means that the two signal wires on the XLR cable are seeing opposite voltages (i.e. the current is flowing opposing directions). On the preamp side, the negative polarity wire is typically shunted to ground through a resistor. I still consider this a balanced audio signal (just not fully differential).
There is a hysteresis type of affect between the opposing voltage of these two wires (since they are so close) that helps stabilize the main signal wire and reduces distortion and helps with natural shielding. This will, in turn, affect the sound quality overall.
In cases where there is a true balanced differential circuit in the preamp, the sound quality will be even better and actually more controlled because the positive and negative polarity signals are being -generated- by the source instead of just having the negative signal echoed back from the amplifier using an opamp type circuit.
There --MAY-- be an improvement in your situation when using an XLR cable if you use something like a Jensen PC-2XR transformer on the amp side. Then use a VERY short RCA cable to connect between the Jensen and the amp (like 6" or so). This keeps the single-ended RCA wire very short and you have the longer XLR cable being truly balanced.
PC-2XR | Jensen Transformers
Just stop you there. Balanced and differential are two different things. One is the impedance on each leg the other antiphase drive. You can have one without the other and often do.
Buy, better build, balanced power amps. But easy, simple, uncomplex circuits!
To get the real advantage of "balance": Reducing of psu-trash, of psu-modulation.
Use ONE psu (voltage) for all channels, all amps: Reducing of psu-differences.-)
To get the real advantage of "balance": Reducing of psu-trash, of psu-modulation.
Use ONE psu (voltage) for all channels, all amps: Reducing of psu-differences.-)
You may be confusing voltage and current.ainami said:
I am puzzled how you can distinguish "the same positive charge" from any other equal amount of charge, given the low drift velocity of electrons in a conductor and the fact that electrons are indistinguishable.
No. Pure nonsense.ainami said:
We were not talking about amp topologies. Complete different issue.
We were talking about balanced connections between equipment.
Jan
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