A novel way to massively improve the SQ of computer audio streaming

[Johnseye]

1 hour ago, mozes said:

I followed this up with a shootout between the sPS-500 and LPS-1.2 feeding the sMS-200ultra. With both PSUs set to 9V, the LPS-1.2 is clearly superior. In comparison, the sPS-500 sounded harsh and flat. This tells me that my sCLK server is not showing its full potential yet with the sPS-500 I use. The LPS-1.2 simply doesn’t have enough juice for it.

 

I'm choking on reading this as I just bought an sPS-500 which should be here today.  I was going to use it within my server on the tX-USBexp & sCLK and independently power the tXultra with the SR7 but it sounds like I'm better off chaining the SR7 through to the tX-USBultra.  That means I'll need to use it elsewhere where an LPS-1.2 would suffice.

 

This also tells me a LPSU trumps a SPSU, regardless of SOtM's applied filtering.

[Johnseye]

7 minutes ago, ElviaCaprice said:

Speaking of SR7, I still have a new one, MR4, sitting in MN, waiting for me.  But now I am thinking it may be overkill for my needs.  Especially if I switch to a Hugo 2 from the 2Qute?  My sCLK EX server runs fine off of the  Uptone LPS 1.1A limitation, which I tried last summer.   

 

Are you saying you'd like to trade for the sPS-500 I just bought?  If so, PM me.

[Johnseye]

58 minutes ago, mozes said:

For the DC cables, I am using 16AWG UPOCC silver 50cm that Steven at Audiosensibility built for me. 

Yes the sPS-500 benefits

from a better power cord and I can comfirm that. Against the LPS-1.2, it is a case by case. For example, on my wireless bridge, I preferred the sPS-500 to the LPS-1.2. Bigger sound stage and more natural flow of music. As for the stock charger, I didn’t like it, I am using an eBay low noise LPS. 

 

All is not lost for me then.  Did you use any EMI/RF shielding inside the sMS?  I think I remember reading you're a fan of ferrite so assume you're using that on the cables.

[Johnseye]

29 minutes ago, mozes said:

The sMS is a demo unit so I am not using any EMI/RF tweaks on it, but I do use ferrites on the LAN cable that is plugged to the sMS, same case with my sCLK server.

 

Any sticky paper shielding in your SPS? 

I did this with the SR7 and LPS. Can't say I know if it helps with those because I did it at the same time as the other components. It has helped a lot overall. 

[Johnseye]

37 minutes ago, LTG2010 said:

My Linear ATX power supply by sean Jacobs arrived today. It needs a few weeks for component burn in but it's already sounding great, large soundstage, great dynamics, silent background, very detailed, neutral, good bass, very pleased, took just under 3 months mainly due to transformer manufacture.

It's a twin transformer design with 9 rails, 3.3v, 5v, 2x12V for the motherboard/CPU, 2x5v for ssd and hdd and 3x9v for SOTM trio.

It comes with a single umbilical connection at power supply and gland that feeds into the server. The wires are colour coded, but bare ended as Sean has an exclusivity agreement with Innuos. Heres my ScLK-ex server.

ATX wiring information is readily available here's a link with some good detail - this is how I did it.

https://en.wikipedia.org/wiki/ATX

I used ATX extension cables by Silverstone, 24 pin and 4 pin for the seperate CPU rail, simply cut off the male connectors to expose the wire and group the ground, 3.3v, 5v & 12V wires together and solder these to your seperate power supply feeds. The ground wires are all common on the motherboard so these can be all connected or daisy chained.

Modern motherboards don't need negative -12v voltages (pin 14), you can ignore these. A linear power supply does not have a 3.3V sensing voltage (pin 13) you can snip that off. You can't turn off your linear power supply from the pc so no need for the power on feed (pin 16). Pin 9 (purple) is the stanby voltage and is 5v, so connect this with your 5v feed (red wires).

Pin 8 (usually grey) is the power ok signal. The atx power supply sends a 5v signal to the motherboard once its all powered up and stable. We don't have this on a linear power supply so we need to 'fool' the motherboard into thinking its receiving a power ok signal, otherwise it won't boot. So we also connect this to the 5v feed. The power ok signal should activate between 100ms - 500ms after the supply is switched on, some motherboards might not boot if this criteria is not met. I had no problems with the supermicro X10, if your's does not boot you can easily get around this with a cheap delay relay from ebay, there are other methods also.

I originally made up some ATX connectors with silver plated copper cables and for powering the hard discs, these sounded awfull, very bright and distorted, so I switched to the Silverstone leads that appear to be tinned plated copper. For the SSD and hard disc I used Neotech OFC copper, amazing how a small piece of cable can clean up the sound. If making up your own SATA power connector, the middle pin is +5v and a pin either side of that is ground. Similarly I used Neotech copper for SOTM boards directly soldered to the board behind the external connectors, thus avoiding external connections and jack plugs.

Alec

 

 

 

Excellent!  Very nice.  Fix those picture links so we can get a better look.

 

Wondering how you attached the sCLK tray to the side of the Streacom case.  Did the screw holes line up and did the screws fit?

[Johnseye]

4 hours ago, tims said:

Yes, thanks. 

I don't know what your plans are with your new PS but it would be interesting to compare how a single 9v supply sounds (as you described above) compared to feeding each of the txUSB-exp, sCLK-ex and txUSBhub-in with their own separate power supplies.

 

I supply my tX-USBexp, sCLK & tX-USBultra with a single 9v supply chained.  The issue with powering them separately is there can be different supplies involved.  We will be testing with an SR7, SR4 and sPS-500.  Would a single SR7 source sound better than including inferior supplies upstream?  How about downstream?

 

A 9 rail supply eliminates that variability and can provide direct power from the rail to individual components.  Is that superior to chaining the 3 devices?

[Johnseye]

5 hours ago, ray-dude said:

 

Thanks @d_elm.  My understanding (very loose, since we only have been able to speak briefly) is that he recommends a specific 6AWG cable.  I suspect it is solid core (based on posts of others), and the typical 6 AWG (and 8AWG) power cable is stranded.  Jim recommends the 10 AWG Romex, which is also solid core.  I've been poking around, but I haven't (yet) found any solid core options in 6 AWG or 8 AWG.

 

I defer to others who've been able to work with Jim more than I have to clarify one way or the other (I hope to chat again with him this week)

 

 

5 hours ago, Bruce Orr said:

I need 80+ feet!!

 

My feeling talking with Jim was that the 6 AWG is not solid, but he does prefer that in the 10.  I'm not exactly sure what it is that Jim does to customize it. I asked that question in the email I just sent him. If he is customizing it, I asked what he is doing to it, and why he prefers the AWG 10 solid over a "standard" AWG 6

 

The 6 awg is stranded.  You'd have a very hard time running solid 6 awg, especially with bends.

[Johnseye]

16 minutes ago, austinpop said:

I just got back from AXPONA 2018 in Chicago. I'll talk about the show in another post, but I just wanted to thank @Johnseye for opening his home and man cave to myself, Larry @lmitche, Chris @Forehaven and my non-CA college buddy with whom I stayed. We had a blast listening and doing comparisons, and John and I will be reporting on that soon. But most of all, it was a blast meeting all of these great guys in person. That is really the point of these shows. 

 

I came away thoroughly impressed with how knowledgeable and accomplished each of them is, not just in computer audio, but in their professional lives. I hope I get to meet more of you in person some day!

 

The time spent at Axpona, meeting those who we have conversations with on a regular basis in these forums, listening to new equipment together, discovering, hanging out and just having a lot of fun, was one of the best times I've ever had at a convention.  Everyone was incredibly friendly and engaging.

 

It was a pleasure to have these guys over and I only wish we could have had more time together.  One of my biggest take aways from that experience was that we had 3 different approaches together in the same room.  Rajiv with the trifecta, myself with the clock modified low powered server and Larry & Chris with the high powered, upsampling PC.  Despite our different approaches we all agreed on everything we heard.  More to come as we document our findings.

 

Larry and Chris are out at the Green Mill tonight seeing Patricia Barber with Lee and May from SOtM.  I wish I could be there.  I'm sure they're having a great time.

[Johnseye]

The Sunningdale Session

 

Sunday afternoon Rajiv @austinpop and his long time friend came by my place after Axpona.  Rajiv and I had loosely planned this out.  His equipment was brought over the night before and powered on.  We hoped to accomplish much more testing than we had time for, but I think it would have taken days to get through everything we wanted to accomplish.  Once we began, we realized we needed to reduce the number of songs used as a benchmark to one or two.  These tracks were Freddie Freeloader from Miles Davis’s Kind of Blue 24/192 and Mahler’s 5^th Symphony: 5. Rondo-Finale, Osmo Vänskä, Minnesota Orchestra, BIS 24/96 upsampled to 24/192.  We both knew these tracks enough to easily discern any change, and both offered differences with musical dynamics.  Roon was used as the player.  No other DSP settings were applied, other than upsampling Mahler to 192.  Both tracks were sourced from my Synology NAS.

 

Equipment used consistently for all tests were as follows:  Paradigm Persona 3F speakers, Benchmark AHB2 amp, Audio Research LS-28 preamp and SOtM tX-USBultra.  All cables were the same.  Speaker cables were from DH Labs, balanced cables were Audioquest Colorado, USB was the Phasure Lush and AC power cables were Shunyata Venom.

 

Equipment changed during the tests were as follows: sMS-200ultra, custom server running Roon ROCK (sCLK-EX providing taps to mobo system, LAN, tX-USBexp and tX-USBultra), Windows 10 running Roon Server, tX-USBexp, SATA Filter 2 amongst other components), Audio Alchemy DDP-1 DAC with PS-5 SMPS, Ayre Codex DAC, Cybershaft OP-14 10 mhz master clock, modified Zyxel switch (sCLK-EX from the sMS-200ultra providing the clock tap), Linear Solutions OCXO modified TP-Link switch and included LPS, Paul Hynes SR7 and SR4, and SOtM sPS-500.

 

We first cycled through a minute or two of about 5 tracks to get a benchmark of my system.

 

We then added Rajiv’s sCLK-EX modified Zyxel switch and the sMS200ultra.  The tX-USBultra powered by the SR7 remained in line just prior to the Audio Alchemy DAC throughout.  The sMS200ultra was powered by the SR4 and the switch was powered by the sPS-500.  My system was powered by the SR7 except for the hard drive being powered by an LPS-1.  After switching back and forth between my system and the sMS200ultra several times we ultimately concluded that my sCLK modified system was slightly smoother while the sMS-200ultra introduced a slightly hard digital edge, or maybe that it didn’t smooth out the edge that is commonly attributed to digital music.  The difference was subtle to the point that we needed to make several swaps back and forth to be sure of what we were hearing. 

 

We then sourced Roon from my Windows 10 PC.  This test was to determine whether the source upstream to the sMS-200ultra had an impact.  Swapping between the Windows 10 PC and my custom server with the sMS-200ultra as the endpoint revealed subtle differences with the custom PC being preferable, having a smoother less edgy sound commonly attributed to digital audio.

 

At this point Larry @lmitche and Chris @Forehaven joined us.

 

Wanting to discern whether there was an audible difference between the SR7 and SR4 we used the 12v DR rail, which had been powering my custom server mobo, to power the sMS-200ultra.  Using the Windows 10 PC we swapped between SR4 and SR7 as the power source to the sMS, all other equipment being equal.  What we all agreed on was that the SR7 elicited more bass, and that this was actually a negative.  Reason being that the additional bass drowned out other frequencies.  In this case we preferred the SR4.  This test would benefit from additional verification.

 

It was Larry who thought of the possible reason for this.  The SR4 is a single rail supply.  All components of the supply are dedicated to that rail, while the SR7 is dual rail sharing some components.  Based on this hypothesis we concluded that dedicated power supplies for each component results in superior SQ.  A big leap, but a very likely possibility that needs additional testing.

 

Next we added the Cybershaft OP-14.  We went back to using my custom server and the Windows 10 PC was no longer used at all.  The OP-14 provided the master clock solely to the sCLK-EX housed in my server.  There was an immediate and noticeable improvement in SQ.  There was more bass, but the bass was very defined to the point of clarity where plucked bass strings were discerned not just blended in a boomy sound.  In fact all instruments were more defined creating an overall richness to the sound.

 

Keeping the Cybershaft in line, I swapped between the Linear Solutions TP Link OCXO modified switch with custom LPS and the Zyxel sCLK-EX modified switch powered by the sPS-500.  I swapped this back and forth several times not informing anyone which was which until after.  The conclusion was that the Linear Solutions switch sounded better.  The difference wasn’t as significant as the OP-14, but it was noticeable.  This test could have been refined more by swapping power supplies between the two.  We could have also tried using the master clock on the sCLK-EX supporting the Zyxel’s clock.

 

Finally we compared the Audio Alchemy DDP-1 and PM-5 SMPS with the Ayre Codex.  The AA was used for all previous tests.  Thanks to Rajiv we took great care to level match.  This was an effort I did not do as well when I reviewed these two DACs two years ago.  My previous level matching was by ear.  In this effort we used an app on Rajiv’s phone.  This made a significant difference and is a lesson I will always keep in mind.  What everyone agreed upon was that the Codex had a richer texture while the AA sounded slightly thinner.

 

We could have spent a lot longer and this was such a fun exercise that I look forward to doing it again.  It was a challenge to get back to listening to the tracks because we were having such a good time talking.  I want to thank Rajiv for making such a big effort to bring his equipment all the way from Austin.  I also want to thank Larry and Chris for driving out to my place.  It was a very busy weekend and all too short.

 

TL;DR

·         A server with sCLK-EX modified motherboard and tX-USBexp sounds slightly better than an sMS-200ultra, all other things being equal.

·         A Linear Solutions OCXO modified TP Link switch with custom LPS sounds slightly better than an sCLK-EX modified Zyxel switch.  The Linear Solutions switch and LPS is an even better improvement over a Netgear GS108 powered by a battery (a test I ran previously).

·         An sMS-200ultra using a single rail 12v SR4 could possibly have SQ benefits over a dual rail 12v DR SR7.  Rajiv and Eric to conduct further tests.

·         A Cybershaft OP-14 master clock without a doubt improves SQ.

·         An Ayre Codex sounds better than an Audio Alchemy DDP- with PS-5.

[Johnseye]

1 minute ago, auricgoldfinger said:

 

Below is an excerpt from a conversation that I had with Paul Hynes several months ago.  Keep in mind that I was considering a power supply with dual regulators.  The sonic penalty will be more audible in a 4-rail SR7 that lacks dual regulators.  For this reason (and also cost), I chose the SR5DRXL to avoid any potential sonic penalties.

 

Moving to the SR7DRMR2XL would provide two galvanically isolated supply rails. There is a slight sonic penalty with having all the transformer secondaries on one transformer core as nothing is absolutely perfect and there will be some small level of interaction due to transient load current swings. This may be audible in a high-resolution system but it would be rather subtle due to the very high supply line rejection of the voltage regulator circuitry in the DR mode.

 

And that is exactly what @lmitche said.  It appears we've heard the sonic penalty of a single transformer.

[Johnseye]

25 minutes ago, austinpop said:

Did you mention the effect of just the reclocked switch to your chain? That was our first experiment. Since your music lives on the NAS, it benefits from the switch even for local playback. I heard what I usually do with this change, but I'll let you describe in your words!

 

I briefly mentioned it in the TL;DR.  It does have a positive impact.  I swapped it with my battery powered GS-108 a few times and the difference is clearly audible.  Not as impactful as the master clock, but still an improvement.  I'll be waiting on the Uptone and SOtM switch reviews before I make a decision.

 

 

25 minutes ago, austinpop said:

One caveat I would add is that in our tests at John's, the Zyxel switch, while being driven by the sCLK-EX, was not reference clocked. So it wasn't quite an apples-to-apples comparison. With more time, we could have swapped the Cybershaft input to the sMS-200ultra that was sCLKing the switch. This illustrates the limitation of the single-output OP-14. 

 

Because the Linear Solutions switch was not master clocked I don't this would have been a fair comparison.  A good one, because of the option to do so with the sCLK, but not apples to apples.  Adrian should add a master clock option.

 

http://thelinearsolution.com/ocxo_switch.html

 

25 minutes ago, austinpop said:

Still, the Linear Solutions switch seems like a winner. More importantly, it seems to be a no-brainer for those who do not have sCLK-EX components in their chain, but want to benefit from the same mechanisms.

 

Regarding the SOtM switch, don't dismiss it yet. Remember, it will have an option to purchase with a 25MHz SMB input, rather than an internal sCLK-EX board. I hope SOtM will price this configuration attractively. In this mode, it would be a replacement for the modded switch people are using. 

 

The only draw back to master clocking is that the components need to be in close proximity.  The switch is one component, at least in my environment, where I'd prefer it not be with the other equipment as it allows me to eliminate an upstream switch, potentially benefiting Tidal streams.

 

25 minutes ago, austinpop said:

Yes, I credit @limniscate for convincing me of the importance of level matching. We did this the first time we compared his Yggy to my Codex. We first listened without careful level matching, and formed a strong preference for one. After level matching, all that went out the window, and we were hard pressed to tell them apart!

 

 

I recently ordered a Holo Spring Level 3 DAC.  I'm looking forward to the many possibilities this brings.  It will be a new chapter as I'll also have a new sCLK motherboard and the ability to upsample to DSD512.  I'll be sure to compare with level matching this time around.

 

[Johnseye]

11 minutes ago, austinpop said:

 

It helps to think of this comparison as follows: how do I get OCXO-level clocking delivered to the switch? In the Linear Solutions design, it is to engineer an OCXO chip directly in the switch. In the sCLK-EX approach, it is to take an OCXO reference clock, connect it to the sCLK-EX master clock input, and distribute to the switch. Without the reference clock in the modded switch, we're not getting the OCXO-level quality. I realize this is a non-technical description. What does it really mean to use an OCXO reference clock to discipline an sCLK-EX clock generator? I guess in layman's terms, and based on what we are hearing, the "quality" of the OCXO reference clock seems to propagate to the outputs of the sCLK-EX.

 

If Linear Solutions offered a master clock connection it would, or could, receive further benefit from synchronized timing with the other devices.  The sCLK is very good.  How good vs OCXO without a master clock is now questionable, at least for a switch.  Is there more to Adrian's switch?  Would the sCLK benefit from OCXO?  Exciting time to be into audio  

[Johnseye]

3 minutes ago, elan120 said:

I am looking forward to this comparison as well.  What input will you be using to feed Holo Spring DAC (USB/I2S...)?

 

Great question.  Holo recently improved the USB to where it should be similar to i2s.  I'm talking with someone in the forum now about buying his Singxer for i2s.  This adds another layer of complexity however.

[Johnseye]

1 minute ago, elan120 said:

I am looking forward to your findings as I also have Holo Spring DAC L3, but older not with the new X208 USB input.  I use Sinxger SU-1 to send signal via I2S to Holo Spring DAC, but I modded mine recently to be sCLK-EX clocked and fed by sCLK-OCX10 with great result.

 

May and Lee were talking with me about that yesterday.  That would mean another sCLK for me.  More cost.  You wouldn't happen to live in the Chicago area would you

 

[Johnseye]

3 minutes ago, BigAlMc said:

 

Thanks @rickca

 

I would need to re-organise some stuff and put the switch closer to the TX-USBUltra but I guess that's not a deal breaker. All hypothetical of course as the switch is not even out and my Aqvox SE is doing a fantastic job currently.

 

Cost aside. Any thoughts on whether there is a theoretical advantage for the sCLK-OX10 clock signal to go directly to a sCLK-EX containing switch, versus via the TX-USBUltra and it's sCLK-EX?

 

Cheers,

Alan

 

Only the cable length.  SOtM uses longish cables in their devices anyway so it shouldn't make a difference.  I'd leverage the TX ultra if you have a tap and the time.

[Johnseye]

5 hours ago, austinpop said:

 

John, the master clock does not apply to the Linear Solutions approach. Consider this. A generic switch has a fixed frequency (say 25MHz) oscillator (i.e. clock) in it. When you use an sCLK-EX approach to improve the switch, you are doing this:

• sCLK-EX's on-board 10MHz reference clock ---- drives ------> frequency synthesizer ----> synthesizes 25 MHz ------ delivers over SMB to -------> switch

When you connect a 10MHz master clock to the sCLK-EX, you are using the superior OCXO clock in the master clock to "discipline" the sCLK-EX's reference clock. So the new chain, with improved SQ, looks like this:

• OCXO-based 10 MHz reference clock ---------- disciplines -----> sCLK-EX''s reference clock ---- drives ------> frequency synthesizer ----> synthesizes 25 MHz ------ over SMB -------> switch

Presumably, the reason we hear an improvement with the above is that the OCXO "goodness" of the reference clock somehow propagates all the way to the switch.

 

The Linear Solutions approach is different. It is putting the OCXO directly in the switch. It is replacing the generic 25MHz clock in the switch itself with an OCXO 25MHz clock. There is no synthesizer, so the design does not lend itself to an external reference clock. This is a different approach.

 

Does that make sense?

 

As for your point about "synchronization." I've reported on this before. Eric and I have done experiments where we constructed chains where all the components were clocked from a single sCLK-EX board (i.e. synchronized), vs. each component with its own sCLK-EX board (i.e. unsynchronized). We heard no difference in SQ between the 2, suggesting no SQ benefit from synchronization. This suggests the improvements come from lowering the phase noise, not necessarily running all components in lock-step.

 

I hope this clarifies things.

 

Somehow I missed your findings that synchronization using a master clock doesn't have any impact on SQ.  If this is the case, then neither the Linear Solutions switch, nor any other device would benefit from a master clock for synchronization purposes.  I believe what you heard, but it bypasses conventional wisdom.  I'll have to look for your test.  If this is the case then there is no reason for a master clock if your devices have an OCXO clock or potentially better like caesium or rubidium.  Depending of course whether timing is the factor.  All you are buying with a master clock is the ability to tap into an OCXO for reference, while potentially using a lesser quality clock on the device.

 

Can you expound on what you understand "discipline" to mean in this context?

 

Based on what you said, the sCLK would be better with an on board OCXO 10MHz reference, avoiding the need for a master.  Other than having another device to sell, I don't know why SOtM would not do this.

 

[Johnseye]

5 minutes ago, austinpop said:

 

Let's be very precise by what we mean by synchronization. 

 

What I though you were asking, and what Eric and I tested empirically, was whether having multiple components clocked by the same sCLK-EX board (let's call this synchronized, although I think if we dig deep into the mechanisms, that may be a misnomer) vs. having components each clocked by their own sCLK-EX boards (let's call this unsynchronized). See this post, experiment 6.

 

Larry @lmitche, I think this is what you and I discussed too - back then.

 

 

Yup. But be careful. There used to be a mistaken view that Rubidium clocks were better than OCXO for audio, but it's turned out to be the opposite. John Swenson can explain this way better than I can:

https://www.computeraudiophile.com/forums/topic/27650-cybershaft-rubidium-clocklow-priced-option/?do=findComment&comment=580808

 

In essence, to quote: A rubidium standard offers NO advantage over the very good OCXO. The rubidium standard has two systems, a rubidium oscillator, which has high jitter but very good long term stability and an OCXO with very low jitter but not as good long term stability.

 

 

I'm at the limit of my detailed understanding of how exactly clock disciplining works. At AXPONA, I asked Lee whether - when you connect the external 10MHz clock to the master clock input - the external clock overrode the internal reference clock? He said no, it was more like synchronization. I've read this mechanism being referred to as disciplining, but don't know the exact circuit topology and mechanisms beyond this.  

 

Academics aside, the practical effect is the same. Adding the master clock improves the SQ as we have heard.

 

 

Yes, certainly. As for why, it's a tradeoff. OCXOs of the quality used in the OCX10 and the Ref 10 are quite expensive. You can't put them in each device in a cost effective way. The fascinating question though is - do you need to?

 

What Roy found was that the chain with Linear Solution (LS)'s switch:

• LS switch (with internal 25MHz OCXO)

sounded better than:

• Ref 10 (10MHz OCXO) > sLCK-EX (in tX-USBultra) > modded DLink switch

I asked Adrian at AXPONA what the phase noise spec for his OCXO chips was. While I don't want to divulge that number without his consent, suffice it to say it was nowhere near the equivalent phase noise number for the Ref 10 or the OCX10. Another caveat is that you can only compare phase noise at the same carrier frequency, and here we are talking about apples (10MHz OCXO) and oranges (25MHz OCXO).

 

I see the sCLK based chain as a leaky sieve. You start out with outstanding phase noise at the reference clock. Mutec are justifiably proud that their phase noise data is observed at the BNC outputs of the Ref 10. But then this phase noise is going to degrade as it traverses the path to the destination - the 25MHz input in the switch's internals. This path is:

1. 50 or 75Ω cable to the Ultra box containing the sCLK-EX
2. BNC connector quality
3. cable from BNC to U.FL connector on the sCLK-EX board
4. quality of the terminator at the sCLK-EX
5. reflections due to imperfect impedance match
6. noise due to synthesis of the 25Mhz clock
7. cable from sCLK-EX tap to the output SMB connector
8. quality of the SMB connector
9. quality of the SMB cable to the switch
10. reflections due to minor impedance mismatches
11. cable from SMB input on switch to internal board

And even this is an incomplete list, I'm sure. The question is after all this chain of corruption, what is the phase noise characteristic of the signal entering the internal switch board? And could you use an OCXO of lesser quality (i.e. cheaper) within the switch that could provide equal or better phase noise?

 

That is the premise of the onboard OCXO, since that architecture looks like this:

• 25 MHz OCXO --- few mm of interconnect ---> 25 MHz clock input for switch's internal board.

Hope all this made sense - I feel like I rambled on.

 

 

 

All makes sense, and agreed except the synchronization.  I'm not referring to single vs multiple sCLK's.  I'm referring to the true job of the master clock, providing a single drum beat to time multiple devices in synchronization.

 

This simple explanation of a word (master) clock is what I'm referring to.  Additionally, why couldn't we use these master clocks, some of which have OCXO crystals?  Those are some used in pro audio and I'm sure there are more.  What makes the OCX10, Ref10 and OP-14 better and do we even know if they are better?

 

 

[Johnseye]

I think I found the answer to my questions when reading up on the REF10.  It looks like it's a reference master clock and not a word master clock.  I have to read up more on the differences between the two.

[Johnseye]

2 minutes ago, MNG said:

 

I’m trying to learn and catch up regarding these clocks, but isn’t it a different thing entirely? I was getting confused myself about this, but I think that the Word Clocks do bring a benefit of synchronicity of timing but these clocks we’re talking about, OCX10, Ref10 etc, are not Word Clocks and they benefit by reducing phase noise, not improving and syncing timing. I hope that’s right anyway because it’s what I was after when buying the OCX10.

 

Yup, that's what I'm starting to gather.  You're correct.  I've missed this critical piece of info which explains the confusion on clock synchronization.

 

[Johnseye]

2 minutes ago, austinpop said:

 

Precisely.

 

 

Word clocks operate at multiples of the sample rate frequencies of 44.1 and 48 kHz.

 

If someone made external OCXO system clocks at the frequencies of interest... multiples of 12 and 25MHz, that would be the equivalent. I’m not aware they exist. Not saying they don’t, just that I’m not aware.

 

So essentially what these reference clocks are, are a better clock than currently in the sCLK with the ability to connect with, and "discipline" other clocks, including the sCLK, at a 10MHz frequency.  There is no synchronization occurring.  I wrongfully assumed with the multiple BNCs that this would be taking place.

 

I need to learn more about what this disciplining is.  I like Adrian's approach better than the spaghetti model.  Larry hit the nail on the head with his earlier comment.  If there is no synchronizing occurring, then why complicate things, introduce cables, potential for EMI/RF, etc.

[Johnseye]

9 minutes ago, MNG said:

 

I agree, but I think price is the denominator here - these clocks are very expensive and it gets cost prohibitive to stick them in each separate device so stick it in one and share it seems to be the prevailing logic. Currently, I’m only clocking my tX-U and I would far rather have just the tX-U without need for a SPS-500 and CLX10 to run alongside.

 

Some very interesting info to be found here: 

 

 

$55 per clock isn't that much if it's built into the components. Especially compared to a $4k reference master. Of course when you're competing against devices without them that cost less people may not understand why the cost difference. 

[Johnseye]

17 minutes ago, MNG said:

 

I must be missing something then? The clock in the tX-U is already pretty good and we’re improving it with these expensive Master Clocks. How is it only 55$? The one in the tX-U must cost that at least?

 

I said $55 because that is not only a number I heard elsewhere for a military spec OCXO, but @seeteeyou mentioned it as well.  Here's a post from @Superdad on the topic.  He's saying they can run in the hundreds for a really good OCXO.  I'm sure it isn't hard to find the cost.

 

Considering what I heard with the Linear Solutions OCXO switch, the fact that the REF 10, Cybershaft and SOtM OCX10 use OCXO, I'm leaning that direction.  I suppose it ultimately comes down to phase noise.  We'll see what the EtherREGEN brings to the table.  If there's a single port that filters out noise and uses a clock as good or better than the Liner Solutions switch, it could be a winner.  We'll see, and it could be a while.

 

 

[Johnseye]

5 minutes ago, Superdad said:

 

Frequency stability is not important for the application!  Only phase-noise at low frequency offset is important.

 

Is phase noise really the only thing we care about in a clock?  Nothing else?

 

 

5 minutes ago, Superdad said:

Lastly, I must say that I find TheLinearSolution's "spec" on its "OCXO Circuit" puzzling.  They state: "Ultralow Jitter: <1ps RMS."  Aside from  being meaningless without a bandwidth range, 1 picosecond is laughably bad.  1 picosecond equals 1,000 femtoseconds.  A $10 Crystek clock is spec'ed at 85 femtoseconds RMS jitter (12kHz~80MHz).

 

As puzzling as it is, and maybe they were lazy or being secretive about sharing their spec, the switch noticeably improved the sound quality.

[Johnseye]

27 minutes ago, LTG2010 said:

Phase noise is measured as frequency phase error -short term oscillator  instability, there is also jitter - timing error. Jitter or timing error causes a loss of detail and focus '3 dimensionality' This is where the sCLK ex excels. Syncing to a OCXO master clock, reduces these timing errors further. Sometimes measurements alone will not predict how the component will effect the 'sound'

 

There we go.  It's not just about phase noise. Thanks LTG2010.

 

Here's a quote from Mutec's REF 10 site:

 

"Ultimately, it is the timing from one sample to another as a digital audio stream is transferred from one device to another that needs to be as precise as possible for best sound quality"

 

So how does the reference clock influence timing from one sample to another as a digital audio stream is transferred from one device to another? 

[Johnseye]

4 minutes ago, Kritpoon said:

 @Johnseye @austinpop Hi... please help to clarify this set as I may have missed something. This setup with the OP-14 is feeding the ref clock signal to the Custom Server (Running Roon Core/Server) -->ehternet-->SMS-200Ultra-->USB-->tX-USBUltra-->USB--->DAC?

 

Or is it

 

Custom Server (Running Roon Core/Server) -->USB-->tX-USBUltra-->USB--->DAC?

 

I am curious for the improvment is SQ with ref clock in the chain on the server side has an immdiate impact on SQ in the chain vs normal server + ref clocked renderer.

 

Thanks.

 

The OP-14 ref clock was connected to the sCLK-EX in my server.  That sCLK's taps were used for my motherboard system and LAN clocks as well as a tX-USBexp and tX-USBultra.  The OP-14 only has one output so we couldn't test it with the server and sMS simultaneously.  I don't think we used the OP-14 on the server when the sMS was in line.  Something we should have done.  Glad you brought it up.