[audioengr]

Tell me how you have it connected.

Steve N.

[AmpDesigner333]

Tell me how you have it connected.

Steve N.

Hey, Steve.   I'm hoping we can have longer to play with the Synchro-Mesh especially since we'll be attending an audio party in a few weeks.  It would be great to A/B.

I'm planning to take some photos and post info soon.  We'll hook it to the AP if we get a chance, too.  Of course, listening is the proof in the pudding.

"After the holidays" action (vendors that were dormant, etc.) is giving us round-the-clock fun.

Can you do me a favor and post the specifications that you feel are most important on this thread?

Some handy links for everyone....

Synchro-Mesh user manual:
http://www.empiricalaudio.com/pdfs/Synchro-Mesh_rev2.0.pdf

Synchro-Mesh web page:
http://www.empiricalaudio.com/products/synchro-mesh

Thanks for starting this thread/topic and for sending us the Synchro-Mesh in the first place.  This is bound to get very interesting!

-Tommy

[Shear Bliss VMPS]

And very expensive too I see.

[audioengr]

Tommy - the object of the Synchro-Mesh is to reduce jitter.  Specifying jitter is a difficult task.  Often you see a jitter number that manufacturers quote.  The problem is that jitter has both a spectrum and a distribution, which makes a single number uninteresting and usually not correlated to listening tests at all.  Many tests have been done with uncorrelated jitter generators that show that uncorrelated jitter can be tolerated up to even 1 nsec or more.

I have been reducing jitter for a LONG TIME, I mean at least 12 years.  This has taught me that the distribution of jitter is usually the easiest to correlate to actual listening tests.  I make DIRECT jitter measurements rather that using a DAC output.  It has also taught me that psec changes in jitter actually can be audible.  I have measured it and heard it.

Other interesting things about the Synchro-Mesh:

1) it is the ONLY device I have heard that seems to actually be immune to incoming jitter.  Lots of products claim this, but testing proves that it is not the case.  I have modded at least 15 DACs in the past, many of which made this claim.  None of them delivered the goods.

2) Both the input and output are galvanically isolated, so this breaks the ground-loop between your source and DAC, an added benefit. IT does not create any new ground loops.

3) The BNC output delivers one of the most accurate S/PDIF outputs of any product.  The voltage is spot-on the spec, the impedance is spot-on the spec and the risetime is faster than virtually any other device on the market, save my own Off-Ramp.  This is why it is critical to use an accurate cable, that is low-loss and well matched to 75 ohms at the cable and connectors.  It is best to use the BNC connector at the output.  The input cable and connector is unimportant because of (1).

4) The Synchro-Mesh can be even better by using my Dynamo Paul-Hynes regulated linear power supply instead of the wall-wart.  This supply is faster regulating and more powerful as well as having a lower noise floor.  It is actually more expensive than the Synchro-Mesh itself, but worth it.

5) My BNC-BNC cable with RCA adapters is unbeaten in the marketplace.  The concept is unexpected, but makes sense technically.  By properly terminating the aerospace quality silver coax to precision 75 ohm BNC connectors, this virtually eliminates any impedance discontinuity at the connector.  The RCA 75 ohm adapters are quite good as well, but they do create a small impedance bump.  Turns out it is more important the terminate to the cable properly than the effect of the RCA adapter.

Steve N.
Empirical Audio

[steve in jersey]

And very expensive too I see.

If you can actually hear, the price you're paying for this is "peanuts" compared to the results of getting rid of "Digittus"(SP) from your playback sources.

I use a Syncro-Mesh w/ my CD transport into my Metrum Hex DAC . The transport straight into the DAC does not display the same amount of rock solid dimensionality & lower frequency clarity without the SM in the signal path. I would imagine even a Sonos becomes seriously more listenable with a SM inline with it to a DAC.

[mfsoa]

Steve N-

Can you use the toslink in and then the coax out (or other "mismatced" combos?)

Any plans to bump the capability to 192?

Thanks

[audioengr]

Steve N-

Can you use the toslink in and then the coax out (or other "mismatced" combos?)

Yes, you can use any combo

Any plans to bump the capability to 192?

I can make a special version at 192 at any time, for a $50 upcharge.

96 was chosen for the stock product because the digital filter in most DACs is better sounding at 96.

Steve N.
Empirical Audio

[AmpDesigner333]

Let me start by saying my experience with the Synchro-Mesh has been very pleasant so far.  Some music seems to "wake up" when using it, resulting in sparkling highs and greater perceived image depth.  This is especially true with 44.1k/16b in and 96k/24b out.

So, "why is this?"....

The DAC DAC is "very immune" to jitter.  I plan to publish the measurement results on the DAC DAC thread soon, but here's a brief explanation of how this is tested.  Jitter at a certain frequency and amplitude is injected into the S/PDIF and the FFT of the DAC DAC's balanced analog output is measured.  There is no measurable difference in performance until the jitter is way beyond anything a properly functioning source would have.  Yes, I realize that jitter is not a single frequency or amplitude, but I'm talking about establishing a threshold using this measurement technique.  There are other techniques, but the thresholds are so high, that it doesn't make sense to keep testing if the water is wet.

That said, the sound (sometimes "improved") I'm hearing is not due to jitter reduction, but rather from sample rate conversion.  The Synchro-Mesh is not "bit perfect", but that's NOT necessarily a bad thing.  There are MANY misconceptions about digital audio out there, and I expect a number of unqualified individuals, who shall remain nameless until they surface, to start throwing them out there.  This kind of thing always seems like a battle, but that's a topic for another day....

Back in the late 90s and several years after, I used sample rate converters in direct digital amps (digital modulation) in order to run the modulator at a fixed rate while allowing multiple source sample rates.  In this case, the input clock and output clocks are asynchronous.  I also received the first Dolby certification ever of a PC based DVD player, and guess what the hardest part was....  Sample rate conversion!  My experience with sample rate conversion taught me lots, but most notably that it's no small feat to make it work well.

So, the Synchro-Mesh must have a simply awesome sample rate converter!  It does an amazing job on some tracks, and I haven't heard anything sound "not as good" through it either.  I'm continuing my listening, and will eventually do some measurements as well.

By the way, we had a bit of a delay due to 32" of snow here over the weekend.  I'd much rather be listening than shoveling any day!

Thanks.

-Tommy O

[SteveMiller]

As one of the few extremly lucky people to have first hand and long term experience with the DAC DAC  in a very mature resolved system I am pleased to agree with Tommy's engineering and design.

I havent experienced the Empirical products first hand, but several other brand name dac's that champion themselves as Jitter-Reducing machines.  That they might be but certainly they were not immune like the DAC DAC seems to be!

I previously needed to use an expensive memory player software installed on a 2010 iMac filled with 12gig of ram just to feed my suppossedly jitter friendly, stable clocked, latest chipped brand name $3500 Dac....even then, I kept trying new cables and isolation devices to make it sound more right....

   With Tommy's DAC DAC in place and a simple USBtoSPDIF, I can happily use iTunes itself, and it sounds better than the memory ever did into the other dac.  In fact the memory player sounds no better than iTunes does now.  That proves to me that without fancy cables, and extra hardware the DAC DAC is just making music like it should, immune to whatever plagues the other devices on the market.  And it plays well with any resonable source I throw at it. 

That other devices such as SRC's may change the sound somewhat, I will not dispute. My point is simply that whatever Tommy has engineered here, does not need to be 'fixed' by any preceeding hardware IMHO.

Wouldn't it be nice to exist in a world where you could buy a new component and take it home, plug it into your system and enjoy its sound without having to buy more products to fix the sound of your new component?   Digital Amplifier Company builds just such things right now. Listen and see!

[audioengr]

Tommy - Does a 96kHz track sound any better through the Synchro-Mesh?  If so, then I think this counters your upsampling theory.

Maybe you need to try the 44.1kHz version of the Synchro-Mesh.  This would determine if the improvement is jitter or upsampling.  I have personally found the 44.1 version to sound better with 44.1 tracks, at least through my own DAC.  My DAC uses a 192 digital filter even for 44.1, so there is no advantage with my DAC to use a 96 SM versus a 44.1 SM.  With DACs that auto select the digital filter for 44.1, it is usually better to use the 96 SM because it avoids the "brick-wall" 44.1 digital filter in the D/A chip.

BTW, my own USB interface sounds better than the Synchro-Mesh because it does NOT upsample.  Upsampling IME does create some audible artifacts, but they are minimal with the Synchro-Mesh.

Have you compared my BNC digital cable to yours?

Best Regards,

Steve N.

[AmpDesigner333]

Tommy - Does a 96kHz track sound any better through the Synchro-Mesh?  If so, then I think this counters your upsampling theory.

Maybe you need to try the 44.1kHz version of the Synchro-Mesh.  This would determine if the improvement is jitter or upsampling.  I have personally found the 44.1 version to sound better with 44.1 tracks, at least through my own DAC.  My DAC uses a 192 digital filter even for 44.1, so there is no advantage with my DAC to use a 96 SM versus a 44.1 SM.  With DACs that auto select the digital filter for 44.1, it is usually better to use the 96 SM because it avoids the "brick-wall" 44.1 digital filter in the D/A chip.

BTW, my own USB interface sounds better than the Synchro-Mesh because it does NOT upsample.  Upsampling IME does create some audible artifacts, but they are minimal with the Synchro-Mesh.

Best Regards,

Steve N.

Steve,

Let's call it my SRC theory as opposed to upsampling, but I believe in the math regarding both.  I'm convinced the issue is not jitter when using the DAC DAC.

As you know, but for the benefit of our readers, simulations can show the artifacts created by various digital processing (such as filtering).  Simulations come in a variety of coverage levels where too simple means inaccurate results and taking absolutely everything into account would make them take years to run on the fastest of supercomputers.

Are you using a standard DSP and writing code, or are you using an SRC chip?

I'd like a quicker way to A/B.  Can you add a bypass switch for that purpose?

Heromi at 96k seemed to sound the same direct as with the Synchro-Mesh.  This is using a very inexpensive USB to S/PDIF converter (sub $100!).

The DAC DAC is just a touch better SNR and THD+N wise at lower rates, as most D/As, but then you lose that extra spatial perception.  I agree with your statement about the brick wall filter at low rates.  To me, this is as much an argument for higher sample rates as simple bandwidth.  One reason I prefer PCM to DSD....  The abundant HF noise from DSD is impossible to filter out without significant side effects.  What are your thoughts on this?  Have you ever compared DSD to PCM of the same tracks?

In any case, most amplifiers can't resolve the added bandwidth of higher sample rates, which is not only about frequency response.  The Maraschino retains control into reactive loads at high frequency, which is not the case with "gobs of feedback" amplifiers.  The advantages of a device like Synchro-Mesh would not be so pronounced with lesser amplifiers.  The combination of good 44.1k tracks to Synchro-Mesh to DAC DAC to Stereo Maraschino (new product) has produced some of the sweetest sound I've heard.  Here's a photo:



Want to send me the 44.1kHz version to try out?

Thanks.

-Tommy

[audioengr]

Are you using a standard DSP and writing code, or are you using an SRC chip?

SRC chip

I'd like a quicker way to A/B.  Can you add a bypass switch for that purpose?

In order not to affect the impedance and therefore signal integrity, I would need two very small switches, glued to the circuit board, one at the input and one at the output and a coax cable internally between them.  This is not like analog.  I think this defeats the objective of fast switching.

Heromi at 96k seemed to sound the same direct as with the Synchro-Mesh.  This is using a very inexpensive USB to S/PDIF converter (sub $100!).

Okay.

The DAC DAC is just a touch better SNR and THD+N wise at lower rates, as most D/As, but then you lose that extra spatial perception.  I agree with your statement about the brick wall filter at low rates.  To me, this is as much an argument for higher sample rates as simple bandwidth.  One reason I prefer PCM to DSD....  The abundant HF noise from DSD is impossible to filter out without significant side effects.  What are your thoughts on this?  Have you ever compared DSD to PCM of the same tracks?

Yes.  I have a couple of test CD's that I used for this years ago.  The DSD was over the top in dynamics, not really live sounding and the PCM was more like being there.  These are classical live performances.

In any case, most amplifiers can't resolve the added bandwidth of higher sample rates, which is not only about frequency response.  The Maraschino retains control into reactive loads at high frequency, which is not the case with "gobs of feedback" amplifiers.  The advantages of a device like Synchro-Mesh would not be so pronounced with lesser amplifiers.  The combination of good 44.1k tracks to Synchro-Mesh to DAC DAC to Stereo Maraschino (new product) has produced some of the sweetest sound I've heard.

Nice.  This was just to give you a taste of what low-jitter can do.  My Off-Ramp USB interfaces are actually much better.

Want to send me the 44.1kHz version to try out?

The 44.1 that I have in stock has the "OTL" mod, which removes the output transformer to achieve even lower jitter.  Does your DAC have a transformer on the S/PDIF input?  If not, then you must make sure that the DAC and SM are powered from the same AC outlet.  This is a good idea anyway.  It will have a ground-loop with the DAC unlike the 96 version that you have already.

If you will pay shipping, I'll loan it to you.

Steve N.

[AmpDesigner333]

Steve,

Thanks for your speedy and well organized reply.

Regarding the BNC cable (which is of excellent quality), I swapped it with two other cables on the input and output without noticing any audible effect.  This was with 44.1k and 96k inputs.  If you remind me next week, I'll test jitter immunity of the DAC DAC again, comparing these cables.  It wouldn't surprise me if there's a difference, but like I mentioned, the amount of jitter required to affect the DAC DAC is obscene.

I get it regarding ground loops and even guest lectured on grounding.  The DAC DAC doesn't have an isolation transformer on the input to avoid having two in a row ---- almost every device we have used as a source has its own isolation on its output.  Same reason as for your OTL version.  I'm not a fan of depending on the connection to the wall for a "good ground".  Same goes for connecting the grounds between components at the wall.  I "beeped out" the Synchro-Mesh power supply DC ground to the input and output and it seems both are isolated, and the power supply itself is isolated as well (I would have been shocked if not, pun intended).  Please confirm.  I suggest removing the transformer from the input side instead of the output side.  As it stands, there are two transformers in a row on the input side (the USB to S/PDIF output is isolated).

Just curious....  Have you ever tried recursive testing (running through the device over and over to study cumulative effects)?  I've seen this done on an SRC before.  Pretty cool, really, as any recursive filtering can be.  For the readers, this is like connecting a chain of 100 (an example number, can be 2 to infinity) "identical" devices together.  The first one gets the input, and you measure (or listen to) the output of the last one.  However, with digital processors, also as an example, you can "record" the output and feed that to the input during the next iteration, so only one device is needed, but the stream is finite length so record/playback is possible.  Another note: the record/playback technique removes cumulative jitter effects.

I just received yet another USB to S/PDIF converter.  This one goes to 384k and runs on Win10 without the need to manually install drivers.  I had it working and sounding "perfect" only a few minutes out of the box.  Too early to say it sounds identical to the others (when functioning properly), but....

Regarding a bypass, I meant a passive one (probably a DPDT).  I'm definitely down with the short signal path thing, but I'm much more likely to lean that way with analog.  To me, digital audio was founded on the ability to make infinite "perfect copies", but this is not the same as with signaling.  That's something very commonly misunderstood, as we agreed on the phone.

Your take on DSD is very interesting.  I'd like to expand on that someday.  Plus, when it comes to jitter, DSD is ultra sensitive on the output side.

This is turning out to be a great thread you started.

Sounds like a plan regarding the 44.1k version.  Please email the shipping cost and I'll get it to you ASAP.  Thanks again.

-Tommy

p.s. I didn't use "quote" to reply because my previous quotes would have disappeared leaving only your answers.  Always fun to put quotes around the word quote.

[audioengr]

I get it regarding ground loops and even guest lectured on grounding.  The DAC DAC doesn't have an isolation transformer on the input to avoid having two in a row ---- almost every device we have used as a source has its own isolation on its output.  Same reason as for your OTL version.  I'm not a fan of depending on the connection to the wall for a "good ground".  Same goes for connecting the grounds between components at the wall.  I "beeped out" the Synchro-Mesh power supply DC ground to the input and output and it seems both are isolated, and the power supply itself is isolated as well (I would have been shocked if not, pun intended).  Please confirm.  I suggest removing the transformer from the input side instead of the output side.  As it stands, there are two transformers in a row on the input side (the USB to S/PDIF output is isolated).

The wall-wart is isolated, as are both input and output of your SM.  I have transformer on the input not for jitter, but to break the ground-loop when using my Dynamo upgrade power supply, which is earth-grounded.  This supply reduces significantly the radiated emissions of the wall-wart, as well as providing lower jitter.  The output transformer is usually necessary for the typical system, but if you are careful, the OTL will get you lower jitter and cleaner signal.

Just curious....  Have you ever tried recursive testing (running through the device over and over to study cumulative effects)?  I've seen this done on an SRC before.  Pretty cool, really, as any recursive filtering can be.  For the readers, this is like connecting a chain of 100 (an example number, can be 2 to infinity) "identical" devices together.  The first one gets the input, and you measure (or listen to) the output of the last one.  However, with digital processors, also as an example, you can "record" the output and feed that to the input during the next iteration, so only one device is needed, but the stream is finite length so record/playback is possible.  Another note: the record/playback technique removes cumulative jitter effects.

Interesting idea.  When I had several available I will try this.

I just received yet another USB to S/PDIF converter.  This one goes to 384k and runs on Win10 without the need to manually install drivers.  I had it working and sounding "perfect" only a few minutes out of the box.  Too early to say it sounds identical to the others (when functioning properly), but....

I'm not aware of ANY designs that don't require some driver to be installed for PC's, even XMOS.  That is except for my really old non-asynch Off-Ramp 3.

Regarding a bypass, I meant a passive one (probably a DPDT).  I'm definitely down with the short signal path thing, but I'm much more likely to lean that way with analog.  To me, digital audio was founded on the ability to make infinite "perfect copies", but this is not the same as with signaling.  That's something very commonly misunderstood, as we agreed on the phone.

I understand what you mean and that is why I need two switches, one at the input and one at the output.  Cannot leave any "stubs" hanging or the signal integrity will suffer big time.  These are edges in the 800psec range.

I'll send you an email tomorrow about the 44.1 version.

Steve N.

[AmpDesigner333]

I'm not aware of ANY designs that don't require some driver to be installed for PC's, even XMOS.  That is except for my really old non-asynch Off-Ramp 3.

I said:
"....without the need to manually install drivers."

The drivers for the peachtree x1, for example, require a complicated procedure to install on Windows, which I couldn't get to work after more than a week of back-and-forth with their support person and on three Windows machines.  I haven't returned it in case I get a Mac.  I heard it doesn't require manual driver installation on a Mac.

The drivers for the NuForce U192S can't be found anymore online.  Without them, you can't run the device.  Luckily, I saved them while the device was still supported only a few months ago.

When I hooked up the Muse converter, no problem, Windows installed the drivers automatically.  No need to go through a procedure, no need to download anything.  Same for Phiree and my new no-name board.  Thanks.

[audioengr]

That's what I meant.  The driver must be installed by the user, versus it being native to the OS.

This chipset must be custom, not m2tech, not XMOS.

Steve N.

[AmpDesigner333]

That's what I meant.  The driver must be installed by the user, versus it being native to the OS.

This chipset must be custom, not m2tech, not XMOS.

Steve N.

C-Media.

Long story, but we had meetings with them years ago, and they even flew us out to Cali for meetings.

Thanks.

-Tommy

[audioengr]

Tommy - how does the 44.1 version sound compared to the 96?

steve N.

[AmpDesigner333]

Tommy - how does the 44.1 version sound compared to the 96?

steve N.

Still forming an opinion....

[audioengr]

Still forming an opinion....

I would definitely run it in 16-bit mode.  Power off, select 16 and power back on.

Steve N.