RCA vs Balanced Cables


Here is my delima:

The DirectStream DAC manual suggests using balanced connections into the pre-amplifier. My pre amp (Spectral DMC-30SV) manual suggests using RCA connections. Any suggestions on which is best - RCA vs Balanced?

The cable run is 10 feet of MIT Magnum MA cables. The DirectStream is hardwired by Ethernet cable to the internet using the Bridge II card.



If you have both types of cables you should try them and see which you like better.

My guess is that you should follow the pre-amp’s advice. In the DS the biggest difference between the two is that balanced better cancels common mode noise. Unless that’s a problem in your system the differences between balanced and unbalanced from the DS shouldn’t be too big.

Try both and determine if you hear a difference.

If you are unwilling to do so, just pick one. I would default to that which the preamp manufacturer recommends. Single-ended sounds wonderful. Balanced is of benefit if your system is in an electrically noisy environment.

Or balanced is great if you need the extra gain that the single-ended (which is lower than average output) provides. In my case the balanced is a clear winner in my system.

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Huh, your (fully balanced?) preamp offers both but the mfr recommends single-end. Can’t imagine why. My system, the balanced sounds better, same cable model, etc. But play around, it’s fun.

Many audio component manufacturers choose to be single ended internally - to a (very) rough approximation it halves the component count and/or cost so either they can sell the unit it at a lower price or they can spend the extra budget on other improvements that they feel add more value or sound quality than doing a balanced implementation. If the internal signal is unbalanced they need to convert from balanced to unbalanced on the inputs and this conversion is usually an add-on (wart) and basically adds more circuitry / noise, etc. to balanced signals. (The converse can also happen - on an otherwise balanced implementation there may be an unbalanced to balanced wart, but often unbalanced to balanced can be done by the already present balanced implementation anyway.)

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My DS DAC seems to be sound thin, quiet, and lacking in dynamics, particularly when compared to other sources (A/B comparisons done with Tidal-MacAir-USB-Chord Mojo-RCA-PrimaLuna HP, Tidal-Roon-Mytek Brooklyn, and my Rega P6-Rega MC Phono-PrimaLuna HP). I’m running Roon into the DS network bridge and ran Tidal-MacAir-USB-DS DAC. Both methods sound similar to each other, but thin when compared to the Mojo or Mytek setup (and Rega for that matter). I’ve updated to Red Cloud and have Bridge 3.5.1 uploaded. I have the DAC set to high gain (low is almost inaudible). Is there a different configuration I should set when using the DS DAC as a line out vs variable (preamp) type input source? Is the difference I’m hearing DSD vs PCM (as I understand the DS converts all digital data to DSD). It’s new (<1 month) so am I just experiencing it’s needed break in period? All suggestions welcome!

Personally I think that your system needs more output from the DAC. The DSD has a lower than average output from single-ended and XLR connections (at least compared to other DAC or payer sources I’ve had). That’s why I use the XLR connections into a fully-balancec preamp which adds even more gain. . . this gives a fullness and body to the sound lacking from the single-ended usage I had before in my system. So my recommendation: if possible, use the XLR outputs, if not use a ver good preamp if you are not already.

Thanks for the response. I read the DS will provide an additional 6dB gain if I use XLR (balanced) connections. Unfortunately, my PrimaLuna only has RCA inputs. Do you have any thoughts or experience with an XLR to RCA adapter? Would I still get the 6dB gain if I used a female XLR to RCA adapter?

I have experience with XLR to RCA adaptors. . . and you won’t get that 6db gain advantage. Is your Prima Luna a power amplifier only? If so you would need to introduce a preamp in between it and the DSD DAC to get more gain, or to use a 1:1 transformer such as this one to use the XLR output and retain the 6db gain (adjustable):




I use this ZBIT to convert the balanced output of my Decware ZTPRE preamp into the single-ended connection needed for my Decware SE84UFO3-25 mono block amps.

My system is the PrimaLuna HP Integrated amp, which I really like.

OK. Then perhaps it has a passive gain input stage on the amplifier and extra gain into the amp may help it. I’m not familiar with Prima Luna. Perhaps someone else has an idea why the DSD sounds thin.

What are some signs that a system is plagued with common mode noise?

At least two things come to mind. Often people have a low level 60Hz/120Hz hum. Sometimes it’s not so low level. Often balanced cables will fix it or at least attenuate it a lot. More subtly HF common mode noise can add a “digital” tizz to a system, sometimes annoying but more often just hiding detail, masking reverb, etc. Unfortunately common mode noise can be converted to differential mode noise pretty easily (http://audiosystemsgroup.com/AES-SCIN-ASGWeb.pdf) so there’s no simple way to use your ears to see what kind of noise is the root of a particular problem. A practical thing to do is to see if a balanced cable helps. If it does, use one :slight_smile:

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Thanks for the great info, Ted - though it’s admittedly a bit unnerving that this may be going on without my even knowing it!

At this moment in time I don’t have the option to run my system completely balanced, so I don’t have the option of even determining by trial/error if the 60Hz/120Hz hum is even occurring.

Perhaps I’ll just need to wait until I can run my system fully balanced (only missing balanced chain in my system is the preamp) to discern whether I hear a difference or not?

To my ears my system is sounding quite nice, but I’m admittedly an amateur in terms of perspective and experience in what quality can truly mean. Though my Bluesound Node 2 into my PS Audio NuWave DSD DAC (coax) into my NAD 326bee (acting as preamp) into my PS Audio Stellar S 300 into my Monitor Audio Silver 300’s…all running UNBALANCED RCA’s from bettercables.com (silver serpent’s) is sounding quite nice.

Perhaps ignorance is bliss? :):smile:

I have all upgraded power cables which are quite nice (for my budget anyways - all audioquest) along with a PS Audio Duet power conditioner with Canare 4S11 speaker cables. Any chance anything in this chain could be a victim of common noise?