Where to install the external clock re: RS130

#1

I have a AfterDark “Queen,” 50 Ohm Sinewave clock on order.

I am looking to get the benefit of an external clock in my setup but am confused to where I can or should connect the clock.

Both my streamer (Hifi Rose RS130) and my DAC (Audio-GD R-7HEMK3) have internal clock inputs. The 50 Ohms is required per the DAC. I connect both devices via i2s. So where should I put the clock. On the DAC or the Streamer? I am a bit confuse why the streamer would even have a external clock input as I would think the signal would be negated once in reached the DAC?

The internal clock of the RS130 is actually pretty good as it is a OCXO clock but it is not used or should I say, “overridden,” by the internal clock of the DAC if I am understanding things correct. Why even put a external clock on a streamer only since there is no DAC, won’t the connected DAC always become the primary clock regardless if the DAC is using it’s internal clock or connected external clock?

My assumption is that I should connect the external clock to the DAC and still use the i2s to i2s connection of the two devices. Please correct me if I am wrong.

#2

I2S bus transmits clock signal. If you reclock it at the DAC anyway (assuming it even can/would reclock I2S connection, as this defeats the purpose), there is no point to bothering with I2S in the first place (well, really there is no point to I2S as an external connector to begin with, but that’s another discussion). If you believe that there is some sonic advantage to I2S (there isn’t) than you should connect the clock to RS130 and have it send an allegedly better-clocked signal to the DAC.

#3

Very helpful @BorisM, thank you.

#4

You’re welcome.

I2S was designed as a bus for sending data (primarily digital audio) with its attendant clock signal, across a circuit board inside a device. It is a perfectly fine bus for doing that. Simple, cheap to build, and works just fine. Later on, PS Audio popularized it as an external connector, to have something distinguishing them from other makers, and solid engineering isn’t something they could use, not having any competent engineers). Since it has never even been designed for external connections, there’s no standard connector, pin-outs, or electrical specs for it. That’s why we get all the people asking how to wire a cable and configure the Rose for connecting to something over I2S, and half the time it doesn’t even work, because everyone has their own idea how to implement it.

I2S is basically an updated S/PDIF connection, that locks your DAC to the clock of the source device, and whatever might happen to the signal as it goes through the cable. One can certainly make a device that works better with I2S (or Toslink, or two cans on a string) than with some other connection, but you basically need to break the other input, as there is nothing inherently superior to I2S.

If you really want to use the external clock, just connect the DAC with any spare USB cable ($5 one would work as well as anything, and USB cables tend to be cheaper than HDMI usually used for I23S), and plug the clock in the DAC. USB Audio is by definition asynchronous, and as long as the DAC is made somewhat correctly, correct timing will be applied to audio data. I very much doubt that it would make any audible difference, or why pay significantly more for RS130 + an external DAC in the first place, when you could just get a 150 or 250 which have perfectly fine clocks (and data goes to the DAC over a proper internal I2S connection already), but if you already have them it’s probably the best connection you can make.

#5

Thank you again @BorisM great insight. This hobby is a complicated one for sure.

#6

It’s complicated, with advanced elec trical engineering and all that involved, and also, because there are good money to be made, and the actual impression of the end result being so subjective there is an incredible number of swindlers, crooks, and simply delusional ignoramuses trying to sell things that do not and can not work (directional network cables? fuses?!) for big money…

#7

Another good point @BorisM . I am somewhat skeptical about external clocks but in theory the concept of a master clock makes sense. Hope I am not wrong, LOL.

#8

In theory, they could be quite useful. If you are running a music production studio and want to keep your ADCs, DACs, and various processors in sync. Maybe, if you were outputting the same signal to multiple DACs and wanted to play them i n exact sync, a common external clock would be useful, too. In practical use for home listening it would have some purpose only if your DACs clock were extremely inaccurate. Extremely – as being orders of magnitude worse than a $5 phone dongle. While I would not exactly put it past some of those audiophile companies to market a $50K DAC with a clock driven by two tired hamsters in a wheel and requiring another $25K in external clocks to work right, generally, anything expensive enough to have a clock input has a clock that is “good enough.”

The clock input is there for marketing reasons. Or, same reasons Rose makes the RS130. There is no practical reason for it to exist, but it sells well to audiophiles, and they are in business to make money, after all.

#9

Ha, funny and informative. Nicely done. And as they say, "there is a sucker (me,) born everyday or as I prefer to say “ignorance is bliss.” LOL @BorisM

#10

I fully agree with what you say. You have well described what and where the clock is used for.
My personal opinion with no offense to anyone.

1 Like
#11

Thanks :slight_smile:

II guess I should add a caveat – hearing is very susceptible to suggestion and it’s very easy to persuade oneself that something (especially if one paid big money for it) makes some incredible difference. If you already have a system with directional Ethernet cables (I can’t even begin to imagine how that would work, but audiophiles swear by them), magic crystals and cable lifters and enjoy the sound of it (and didn’t spend your kids’ inheritance on it) might as well keep it; it makes you happy. But when adding new things, I believe that one should check if they at least could work…