Clock experiments

[John49]

Originally Posted by custodian

Try it. That's a very good unit so worth doing. Does the clock input take a standard 10mHz signal?

From the manual, the frequency used is either 44.1, 88.2 or 176.4 kHz.

[custodian]

Originally Posted by John49

From the manual, the frequency used is either 44.1, 88.2 or 176.4 kHz.

Yes, that's the frequencies generated in the Marantz for different digital music signals. The external clock control is usually 10mhz. Is it not specified in the manual?

[crwilli]

Since I am learning fast (but still near the bottom of the curve) and have found myself in two threads on a new reclocking device from Wyred 4 sound and it seems these threads are largely about the same technology, how can there be a device that works at $399 and you are talking about devices where the parts cost $35,000?

It is mind blowing to me. I get there is a point of diminishing returns for almost everything and I celebrate those who won't accept being anywhere but at the pinnacle, but Geesh, what are the differences here?

Sent from my iPad using A.Aficionado

[Masterlu]

Originally Posted by crwilli

Since I am learning fast (but still near the bottom of the curve) and have found myself in two threads on a new reclocking device from Wyred 4 sound and it seems these threads are largely about the same technology, how can there be a device that works at $399 and you are talking about devices where the parts cost $35,000?

It is mind blowing to me. I get there is a point of diminishing returns for almost everything and I celebrate those who won't accept being anywhere but at the pinnacle, but Geesh, what are the differences here?

Sent from my iPad using A.Aficionado

Rubidium Clock:

Rubidium standard - Wikipedia, the free encyclopedia

Femto Clock:

Low Phase Noise Clock Synthesizers, Low Jitter Clocks - FemtoClock® | IDT

About Low-jitter Clocks
Jitter can be defined as the undesired deviation from an ideal periodic timing signal. Jitter may be observed in characteristics such as the frequency, phase, or amplitude of successive pulses. High levels of jitter can result in significant undesired system behavior in high-performance applications. IDT offers the industry's leading portfolio of low-jitter clock synthesizers and phase-locked oscillators (PLL oscillators) to meet the needs of virtually any application.

[custodian]

Originally Posted by crwilli

Since I am learning fast (but still near the bottom of the curve) and have found myself in two threads on a new reclocking device from Wyred 4 sound and it seems these threads are largely about the same technology, how can there be a device that works at $399 and you are talking about devices where the parts cost $35,000? It is mind blowing to me. I get there is a point of diminishing returns for almost everything and I celebrate those who won't accept being anywhere but at the pinnacle, but Geesh, what are the differences here? Sent from my iPad using A.Aficionado

Sorry, just not that simple.

Digital clocking is a complex subject with lots of different ways to do it, each with their benefits.

Devices used include crystals, rubidium sources, caesium decay sources, GPS clocks, hydrogen masers and others.

Some of these are incredible at long term timing so will be accurate to fractions of a second over a million years; others are good at keeping the time signal constant over very short intervals.

In audio, we are concerned about short term constancy.

Less expensive audio devices use an OTXO crystal; better equipment uses an OCXO crystal. Whilst OCXO devices are not hugely expensive, there is manufacturing variation in performance, so manufacturers of specialist equipment will often specify at the top end of the performance curve which adds greatly to manufacturing cost because of high scrap losses.

The OCXO crystal has very good short term performance, even compared to the more expensive devices above.

The external system clock used by DCS is an OCXO crystal.

To try to get better performance, people have tried rubidium clocks ( sometimes referred to as atomic clocks) which have better long term (drift) performance. These sre used in huge numbers in the telecoms industry and lots of cheap surplus devices packaged into a complete unit can be bought through surplus channels and eBay for around $100. The problem is that short term performance is generally poorer than a good OCXO crystal. Clever design and using rubidium and OCXO in the same device can give a clock with the best of both worlds.

Caesium, gps clocks, hydrogen masers etc are best ignored because of cost, complexity or performance issues.

A specialist rubidium clock for audio use can make a positive difference to sound quality. There are several on the market ranging from the Antelope device at below $5k up to the Esoteric clock. All will make the audio system sound different.

Finding the improvements from clock changes interesting, I talked with experts in digital timing in research applications and the recommendation for ultimate short term stability in a practical device was a very special variant of an OCXO crystal called a BVA in which a specially cut crystal is suspended in a complex structure and temperature stabilised in a double oven. The BVA based clock is typically 10x better than the best OCXO in the key parameters that effect use in audio systems. Problem is cost with the only available complete audio clock now being $37k.

People on audio forums have argued over the differences between analog and digital music reproduction for ever. All I can say is that in a good system, the BVA clock removes digital edge (presumably low level jitter) to a point that brings analog and digital much closer together.

I sound a bit like a missionary on this subject: I don't mean to become a preacher. I am not an expert in this field and the views above are grossly oversimplified and incomplete. Hopefully it has provided a useful overview of the options. I'm happy to demo the effects of my own BVA clock to anyone who happens to find themselves in this part of the UK

[cmarin]

Custodian,

Not preachy at all. Quite the contrary, thank you for explaining a complex subject so that even newbies such as myself can increase, even minimally, our understanding of a very complex subject.

As a friend of mine is fond if saying: "if you're not careful, you might just learn something".

Thanks again.

[chessman]

Originally Posted by cmarin

Custodian,

Not preachy at all. Quite the contrary, thank you for explaining a complex subject so that even newbies such as myself can increase, even minimally, our understanding of a very complex subject.

As a friend of mine is fond if saying: "if you're not careful, you might just learn something".

Thanks again.

+1!

[crwilli]

Originally Posted by cmarin

Custodian,

Not preachy at all. Quite the contrary, thank you for explaining a complex subject so that even newbies such as myself can increase, even minimally, our understanding of a very complex subject.

As a friend of mine is fond if saying: "if you're not careful, you might just learn something".

Thanks again.

EXACTLY! That is why I have no issue showing my ignorance on this topic. I assume there are others out there who may also benefit. HUGE fan of 'trickles down'.

[custodian]

Thanks Guys, glad it was useful. I feel like the teacher who is half a page ahead of the pupils. Problem is you now know as least as much as I do! I need to read some more so I can get ahead again

[JCR]

Originally Posted by custodian

I sound a bit like a missionary on this subject: I don't mean to become a preacher. I am not an expert in this field and the views above are grossly oversimplified and incomplete. Hopefully it has provided a useful overview of the options. I'm happy to demo the effects of my own BVA clock to anyone who happens to find themselves in this part of the UK

Thanks for this clear explanation custodian! This is the clearest and best overview of the digital clock options/challenges I have seen and is quite useful! I will echo others here as not to worry about your "preaching"! We all need a little bit of that in this topic

I just wish that was more then a single $37k alternative out there

Thanks again for the clarity of your explanations!

Jacques