flkin Posted September 6, 2018 Share Posted September 6, 2018 Mutec has been quiet for sometime even their service team doesn't reply quickly anymore. Apparently they are "busy with work overload preparing for a long yearly closing of the company on the 10th to 20th of Sept". Not good to ignore customers PinkFaun - Vinnie Rossi - YBA - QSA Lanedri - Wilson Link to comment
Popular Post julian.david Posted September 7, 2018 Popular Post Share Posted September 7, 2018 On 9/5/2018 at 10:24 PM, Confused said: I have just noticed that @julian.david has not posted on CA since the start of the year. A shame, because he has provided some great insight with many of his posts. Anyway, it therefore looks like we are unlikely to get a direct answer to the clock aging question any time soon. Hi all, Has it really been a year? Time flies I guess. Well, mea culpa. I became a dad a year ago and had to cut back a little bit. Turns out that my son doesn't care about audiophile discussions quite as much as I had hoped (yet!) - although he does thoroughly enjoy Paul Simon's Graceland 25th Anniversary Edition as he should ? Anyway, rest assured that I have been following these threads and I tried to be available for questions as much as I can. BTW, MUTEC has started advertising on the CA forum to show our support for the community. Regarding the aging questions I'll check back with Christian Peters as he is the one sourcing the parts and so he's intimately familiar with the oscillator and other components. He's about to leave for vacation but I'm hoping he'll have the chance to give me some insights. Thanks, Julian Superdad and str-1 2 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
Popular Post julian.david Posted September 7, 2018 Popular Post Share Posted September 7, 2018 On 9/6/2018 at 6:02 AM, flkin said: Mutec has been quiet for sometime even their service team doesn't reply quickly anymore. Apparently they are "busy with work overload preparing for a long yearly closing of the company on the 10th to 20th of Sept". Not good to ignore customers Look, MUTEC is a small company without a call center in India. Instead you get an actual response from a human being and quite often from the CEO himself. Chris takes very little vacation, but every once in a while he takes a week or 10 days and that does in fact mean that the office is closed. That has absolutely nothing to do with ignoring customers. mourip, auricgoldfinger and Superdad 1 2 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
austinpop Posted September 7, 2018 Share Posted September 7, 2018 @julian.david Great to see you back on CA. Congrats on a year of fatherhood! Regarding the aging question, I look forward to the answer. julian.david 1 My Audio Setup Link to comment
sam1000 Posted September 7, 2018 Share Posted September 7, 2018 Congratulations and welcome back Julian! I read somewhere on the forum that you are planning to sell an OEM cable to go with Ref10. What is the tentative timeline for the release. julian.david 1 Link to comment
andresz Posted September 8, 2018 Share Posted September 8, 2018 Hello. I have a NVIDIA Shield TV and was wondering whether its USB is compatible with the Mutec MC USB 3+? Thx in advance. julian.david 1 Link to comment
Popular Post JohnSwenson Posted September 10, 2018 Popular Post Share Posted September 10, 2018 I'm NOT from Mutec, but I have a little bit of knowledge about crystal oscillators so I hopefully can offer some insight as to what aging is. First off we need to understand that there is not just one aspect about crystal oscillators that have numbers, people here tend to like to latch onto numbers as figures of merit, but this can be fraught with danger since there are at least there different aspect of crystal oscillators that have numbers, before you start comparing numbers you ABSOLUTELY HAVE to understand which aspects those numbers refer to otherwise you are comparing surface tension to the color of the peel of an orange. There are two primary aspects of a crystal oscillator: 1) phase noise (I have written exhaustively about this early in this thread so I will not duplicate it all here) This is not a single number, it is a graph. This graph is the phase noise as an off set from the "carrier", which is the frequency of the signal coming from the oscillator. In a nutshell no oscillator produces a perfectly "pure" frequency. They all vary a little bit over time. Phase noise looks at the rapidly varying frequency changes. It is plotted in regards to frequency. If the output frequency varies a little higher, then a little lower, then a little higher and does this at a regular rate, this will show up as a spike in the graph (refered to as a "spur"). Real oscillators rarely do this, they kind of randomly fluctuate in frequency, such that this plot looks like a jagged continuous line. USUALLY much higher in value at the lower frequencies than the higher frequencies. From listener reports it seems that the lower offsets, (around 10Hz), seem to be the most import for audio. Unfortunately these are usually the most difficult to improve. 2) Actual frequency of the output. Due to above there is no such thing as AN actual frequency, it is wandering around. So the term "frequency of the output" is some form of averaging over time. That process can vary all over the place and is very rarely specified. Which of course makes comparing numbers rather difficult unless the same test equipment is used in exactly the same way. For example I have a frequency counter which has at least 30 different ways of measuring frequency, which will all give slightly different numbers. #2 has several different subcategories: #2.1) Accuracy. This is just the frequency out of the box. A high accuracy oscillator might be within 10 Hz of the number specified on the can and a lower accuracy one might be within 200Hz of the number on the can. Usually specified in Parts Per Million (PPM), thus a 1 PPM 10MHz oscillator can be up to 10Hz off the specified 10MHz. Some are so good they are specified in parts per billion (PPB). Unless it is pretty grossly off, this is pretty much unimportant for audio. #2.2) Temperature coefficient. All oscillators will change their frequency with a change in temperature, the Temperature coefficient (Tempco) specifies how much. It is usually measured in PPM per degree C. Unfortunately it is not a single number. Take an oscillator at 25C, raise the temp 1C and you will have a certain change in frequency, Start with the oscillator at 50C and change it one degree and you will get a VERY different change in frequency. All crystal oscillators have some temperature where a small change in temperature makes almost no difference in frequency, if you are significantly away from this temperature the change can be VERY large for even a fairly small change in frequency. Because this is measured in PPM/C a lot of people confuse it and accuracy since they both have PPM in the units but they are VERY different things, You can have high accuracy and lousy Tempco, or lousy accuracy and low Tempco. This has SOME affect on audio, but not a lot. The primary effect is at warm up, when a device is is turned on and the temperature inside the box is increasing. During this time the changing frequency can make a small audio difference. After reaching thermal equilibrium the Tempco has almost no effect on audio. #2.3) Aging. This is the long term change in frequency over long time periods (measured in years). Most crystal oscillators have a fairly large change in frequency from year to year. During the first few years this is fairly large, then slowly goes down to almost no change after about say 15 years or so. Aging has essentially zero impact on audio. #1 is the only one that has any significant impact on audio. Of the #2 categories Tempco is the only one which will have some impact on audo, but only during warmup. After the temperature settles down, almost no impact. So in summary, spend money on low close in phase noise, money spent on high accuracy, low Tempco or low aging, is usually just throwing away your money. The OCXO is an exception to this, see below. In particular a TCXO (temperature compensated crystal oscillator) is almost never a good thing for audio. A TCXO, has a normal crystal oscillator and a temperature sensor of some sort. The voltage from the temperature sensor is fed into a port on the crystal oscillator which causes its frequency to change with a varying voltage. This setup so it does some degree of cancellation of the crystal Tempco. So now we have a temperature sensor with almost always some degree of noise on the voltage output, feeding an input port which changes the frequency, thus rapidly varying the frequency, what is this called? Phase noise. Thus TCXOs ALWAYS have higher phase noise than a regular crystal oscillator using the same crystal and circuit minus the compensation. Yes it might have a smaller impact during warm up, but sound worse otherwise. Not usually a good use of money. The type of crystal used in common crystal oscillators is what is called an AT cut. Its primary claim to fame is that the temperature where the zero Tempco appears ( sometime called the Tempco threshold or "knee" of the Temcp curve) happens near normal room temperature. This gives pretty good temperature behavior without doing anything else. But they do not have the best performance in other parameters. In particular for audio the phase noise of a different cut, called the SC cut, is much lower. BUT the knee in the Tempco curve is way up in the 90C range, at room temperature the Tempco is so bad that even a small temperature change drastically changes the frequency, so even for audio it is useless. This is where the OCXO comes in, the primary purpose is to raise the temperature of the SC cut crystal so it is sitting right at the knee of the Tempco. This gives an oscillator with a very low Tempco, very low aging and very low phase noise. Not all OCXOs are created equal, in particular the less expensive OCXOs (say less than $100) do not use a crystal and circuit with particularly low phase noise, but they DO have very low Tempco and low aging, but the phase noise is no better than a $10 regular crystal oscillator. Again this is just a waste of money, you are spending money on something that doesn't make sound better. (note this is "new" price, not what you can get on ebay for a used one). BUT if you spend the money on a very special SC cut crystal and very special circuitry you can get the lowest phase noise of any oscillator known. It is not cheap, but this type of OCXO IS the way to get the lowest phase noise. OCXOs at this level also give you very low aging and very low Tempco, but these are not primarily the main reason for getting one of these OCXOs. Unfortunately for audio, most applications (other than audio) want very good specs for ALL the parameters, it should be possible for the manufacturers to optimize for phase noise only, thus giving us lower cost oscillators since they are not trying get say extremely low aging. One other VERY important aspect about phase noise: comparing charts can ONLY be done if the frequencies are the same. The phase noise for an oscillator increacess by 6dBc/root Hz per octave of the oscillator frequency. Thus of you have plot for a 10 MHz oscillator and one for the same model oscillator at 20 MHz, the numbers will be 6 dBc/ root Hz higher. If you take that 20 MHz output and run it through a good flip flop, dividing the frequency by two, you will get the same phase noise plot as the 10MHz version. So be VERY careful when comparing phase noise from different oscillators , they either need to be at the same frequency or you apply the 6 dBc/ root Hz rule. (explaining that rule is a little complicated so just take my word for it) Sooo as far as aging is concerned, spec sheet aging has nothing to do with audio. John S. Superdad, mourip, d_elm and 11 others 2 7 5 Link to comment
afrancois Posted September 10, 2018 Share Posted September 10, 2018 1 hour ago, JohnSwenson said: I'm NOT from Mutec, but I have a little bit of knowledge about crystal oscillators so I hopefully can offer some insight as to what aging is. First off we need to understand that there is not just one aspect about crystal oscillators that have numbers, people here tend to like to latch onto numbers as figures of merit, but this can be fraught with danger since there are at least there different aspect of crystal oscillators that have numbers, before you start comparing numbers you ABSOLUTELY HAVE to understand which aspects those numbers refer to otherwise you are comparing surface tension to the color of the peel of an orange. There are two primary aspects of a crystal oscillator: 1) phase noise (I have written exhaustively about this early in this thread so I will not duplicate it all here) This is not a single number, it is a graph. This graph is the phase noise as an off set from the "carrier", which is the frequency of the signal coming from the oscillator. In a nutshell no oscillator produces a perfectly "pure" frequency. They all vary a little bit over time. Phase noise looks at the rapidly varying frequency changes. It is plotted in regards to frequency. If the output frequency varies a little higher, then a little lower, then a little higher and does this at a regular rate, this will show up as a spike in the graph (refered to as a "spur"). Real oscillators rarely do this, they kind of randomly fluctuate in frequency, such that this plot looks like a jagged continuous line. USUALLY much higher in value at the lower frequencies than the higher frequencies. From listener reports it seems that the lower offsets, (around 10Hz), seem to be the most import for audio. Unfortunately these are usually the most difficult to improve. 2) Actual frequency of the output. Due to above there is no such thing as AN actual frequency, it is wandering around. So the term "frequency of the output" is some form of averaging over time. That process can vary all over the place and is very rarely specified. Which of course makes comparing numbers rather difficult unless the same test equipment is used in exactly the same way. For example I have a frequency counter which has at least 30 different ways of measuring frequency, which will all give slightly different numbers. #2 has several different subcategories: #2.1) Accuracy. This is just the frequency out of the box. A high accuracy oscillator might be within 10 Hz of the number specified on the can and a lower accuracy one might be within 200Hz of the number on the can. Usually specified in Parts Per Million (PPM), thus a 1 PPM 10MHz oscillator can be up to 10Hz off the specified 10MHz. Some are so good they are specified in parts per billion (PPB). Unless it is pretty grossly off, this is pretty much unimportant for audio. #2.2) Temperature coefficient. All oscillators will change their frequency with a change in temperature, the Temperature coefficient (Tempco) specifies how much. It is usually measured in PPM per degree C. Unfortunately it is not a single number. Take an oscillator at 25C, raise the temp 1C and you will have a certain change in frequency, Start with the oscillator at 50C and change it one degree and you will get a VERY different change in frequency. All crystal oscillators have some temperature where a small change in temperature makes almost no difference in frequency, if you are significantly away from this temperature the change can be VERY large for even a fairly small change in frequency. Because this is measured in PPM/C a lot of people confuse it and accuracy since they both have PPM in the units but they are VERY different things, You can have high accuracy and lousy Tempco, or lousy accuracy and low Tempco. This has SOME affect on audio, but not a lot. The primary effect is at warm up, when a device is is turned on and the temperature inside the box is increasing. During this time the changing frequency can make a small audio difference. After reaching thermal equilibrium the Tempco has almost no effect on audio. #2.3) Aging. This is the long term change in frequency over long time periods (measured in years). Most crystal oscillators have a fairly large change in frequency from year to year. During the first few years this is fairly large, then slowly goes down to almost no change after about say 15 years or so. Aging has essentially zero impact on audio. #1 is the only one that has any significant impact on audio. Of the #2 categories Tempco is the only one which will have some impact on audo, but only during warmup. After the temperature settles down, almost no impact. So in summary, spend money on low close in phase noise, money spent on high accuracy, low Tempco or low aging, is usually just throwing away your money. The OCXO is an exception to this, see below. In particular a TCXO (temperature compensated crystal oscillator) is almost never a good thing for audio. A TCXO, has a normal crystal oscillator and a temperature sensor of some sort. The voltage from the temperature sensor is fed into a port on the crystal oscillator which causes its frequency to change with a varying voltage. This setup so it does some degree of cancellation of the crystal Tempco. So now we have a temperature sensor with almost always some degree of noise on the voltage output, feeding an input port which changes the frequency, thus rapidly varying the frequency, what is this called? Phase noise. Thus TCXOs ALWAYS have higher phase noise than a regular crystal oscillator using the same crystal and circuit minus the compensation. Yes it might have a smaller impact during warm up, but sound worse otherwise. Not usually a good use of money. The type of crystal used in common crystal oscillators is what is called an AT cut. Its primary claim to fame is that the temperature where the zero Tempco appears ( sometime called the Tempco threshold or "knee" of the Temcp curve) happens near normal room temperature. This gives pretty good temperature behavior without doing anything else. But they do not have the best performance in other parameters. In particular for audio the phase noise of a different cut, called the SC cut, is much lower. BUT the knee in the Tempco curve is way up in the 90C range, at room temperature the Tempco is so bad that even a small temperature change drastically changes the frequency, so even for audio it is useless. This is where the OCXO comes in, the primary purpose is to raise the temperature of the SC cut crystal so it is sitting right at the knee of the Tempco. This gives an oscillator with a very low Tempco, very low aging and very low phase noise. Not all OCXOs are created equal, in particular the less expensive OCXOs (say less than $100) do not use a crystal and circuit with particularly low phase noise, but they DO have very low Tempco and low aging, but the phase noise is no better than a $10 regular crystal oscillator. Again this is just a waste of money, you are spending money on something that doesn't make sound better. (note this is "new" price, not what you can get on ebay for a used one). BUT if you spend the money on a very special SC cut crystal and very special circuitry you can get the lowest phase noise of any oscillator known. It is not cheap, but this type of OCXO IS the way to get the lowest phase noise. OCXOs at this level also give you very low aging and very low Tempco, but these are not primarily the main reason for getting one of these OCXOs. Unfortunately for audio, most applications (other than audio) want very good specs for ALL the parameters, it should be possible for the manufacturers to optimize for phase noise only, thus giving us lower cost oscillators since they are not trying get say extremely low aging. One other VERY important aspect about phase noise: comparing charts can ONLY be done if the frequencies are the same. The phase noise for an oscillator increacess by 6dBc/root Hz per octave of the oscillator frequency. Thus of you have plot for a 10 MHz oscillator and one for the same model oscillator at 20 MHz, the numbers will be 6 dBc/ root Hz higher. If you take that 20 MHz output and run it through a good flip flop, dividing the frequency by two, you will get the same phase noise plot as the 10MHz version. So be VERY careful when comparing phase noise from different oscillators , they either need to be at the same frequency or you apply the 6 dBc/ root Hz rule. (explaining that rule is a little complicated so just take my word for it) Sooo as far as aging is concerned, spec sheet aging has nothing to do with audio. John S. Thank you John. Another example of UpTone sharing their knowledge. A real example for the HiFi industry. Looking forward to the answer from Mutec as well. Link to comment
julian.david Posted September 10, 2018 Share Posted September 10, 2018 On 9/8/2018 at 8:45 AM, andresz said: Hello. I have a NVIDIA Shield TV and was wondering whether its USB is compatible with the Mutec MC USB 3+? Thx in advance. Hi Andresz, I got your PM about this. Let me do some research please and get back to you ASAP. Thanks, Julian MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
julian.david Posted September 10, 2018 Share Posted September 10, 2018 On 9/7/2018 at 7:46 PM, sam1000 said: Congratulations and welcome back Julian! I read somewhere on the forum that you are planning to sell an OEM cable to go with Ref10. What is the tentative timeline for the release. It's something we're still looking into, but progress has been a little slow because we're currently focused on a much bigger, and (I think) more exciting project... I'll let you know as soon as there's news on the cable front though. Julian Confused 1 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
Popular Post julian.david Posted September 10, 2018 Popular Post Share Posted September 10, 2018 9 hours ago, JohnSwenson said: I'm NOT from Mutec, but I have a little bit of knowledge about crystal oscillators so I hopefully can offer some insight as to what aging is. First off we need to understand that there is not just one aspect about crystal oscillators that have numbers, people here tend to like to latch onto numbers as figures of merit, but this can be fraught with danger since there are at least there different aspect of crystal oscillators that have numbers, before you start comparing numbers you ABSOLUTELY HAVE to understand which aspects those numbers refer to otherwise you are comparing surface tension to the color of the peel of an orange. There are two primary aspects of a crystal oscillator: 1) phase noise (I have written exhaustively about this early in this thread so I will not duplicate it all here) This is not a single number, it is a graph. This graph is the phase noise as an off set from the "carrier", which is the frequency of the signal coming from the oscillator. In a nutshell no oscillator produces a perfectly "pure" frequency. They all vary a little bit over time. Phase noise looks at the rapidly varying frequency changes. It is plotted in regards to frequency. If the output frequency varies a little higher, then a little lower, then a little higher and does this at a regular rate, this will show up as a spike in the graph (refered to as a "spur"). Real oscillators rarely do this, they kind of randomly fluctuate in frequency, such that this plot looks like a jagged continuous line. USUALLY much higher in value at the lower frequencies than the higher frequencies. From listener reports it seems that the lower offsets, (around 10Hz), seem to be the most import for audio. Unfortunately these are usually the most difficult to improve. 2) Actual frequency of the output. Due to above there is no such thing as AN actual frequency, it is wandering around. So the term "frequency of the output" is some form of averaging over time. That process can vary all over the place and is very rarely specified. Which of course makes comparing numbers rather difficult unless the same test equipment is used in exactly the same way. For example I have a frequency counter which has at least 30 different ways of measuring frequency, which will all give slightly different numbers. #2 has several different subcategories: #2.1) Accuracy. This is just the frequency out of the box. A high accuracy oscillator might be within 10 Hz of the number specified on the can and a lower accuracy one might be within 200Hz of the number on the can. Usually specified in Parts Per Million (PPM), thus a 1 PPM 10MHz oscillator can be up to 10Hz off the specified 10MHz. Some are so good they are specified in parts per billion (PPB). Unless it is pretty grossly off, this is pretty much unimportant for audio. #2.2) Temperature coefficient. All oscillators will change their frequency with a change in temperature, the Temperature coefficient (Tempco) specifies how much. It is usually measured in PPM per degree C. Unfortunately it is not a single number. Take an oscillator at 25C, raise the temp 1C and you will have a certain change in frequency, Start with the oscillator at 50C and change it one degree and you will get a VERY different change in frequency. All crystal oscillators have some temperature where a small change in temperature makes almost no difference in frequency, if you are significantly away from this temperature the change can be VERY large for even a fairly small change in frequency. Because this is measured in PPM/C a lot of people confuse it and accuracy since they both have PPM in the units but they are VERY different things, You can have high accuracy and lousy Tempco, or lousy accuracy and low Tempco. This has SOME affect on audio, but not a lot. The primary effect is at warm up, when a device is is turned on and the temperature inside the box is increasing. During this time the changing frequency can make a small audio difference. After reaching thermal equilibrium the Tempco has almost no effect on audio. #2.3) Aging. This is the long term change in frequency over long time periods (measured in years). Most crystal oscillators have a fairly large change in frequency from year to year. During the first few years this is fairly large, then slowly goes down to almost no change after about say 15 years or so. Aging has essentially zero impact on audio. #1 is the only one that has any significant impact on audio. Of the #2 categories Tempco is the only one which will have some impact on audo, but only during warmup. After the temperature settles down, almost no impact. So in summary, spend money on low close in phase noise, money spent on high accuracy, low Tempco or low aging, is usually just throwing away your money. The OCXO is an exception to this, see below. In particular a TCXO (temperature compensated crystal oscillator) is almost never a good thing for audio. A TCXO, has a normal crystal oscillator and a temperature sensor of some sort. The voltage from the temperature sensor is fed into a port on the crystal oscillator which causes its frequency to change with a varying voltage. This setup so it does some degree of cancellation of the crystal Tempco. So now we have a temperature sensor with almost always some degree of noise on the voltage output, feeding an input port which changes the frequency, thus rapidly varying the frequency, what is this called? Phase noise. Thus TCXOs ALWAYS have higher phase noise than a regular crystal oscillator using the same crystal and circuit minus the compensation. Yes it might have a smaller impact during warm up, but sound worse otherwise. Not usually a good use of money. The type of crystal used in common crystal oscillators is what is called an AT cut. Its primary claim to fame is that the temperature where the zero Tempco appears ( sometime called the Tempco threshold or "knee" of the Temcp curve) happens near normal room temperature. This gives pretty good temperature behavior without doing anything else. But they do not have the best performance in other parameters. In particular for audio the phase noise of a different cut, called the SC cut, is much lower. BUT the knee in the Tempco curve is way up in the 90C range, at room temperature the Tempco is so bad that even a small temperature change drastically changes the frequency, so even for audio it is useless. This is where the OCXO comes in, the primary purpose is to raise the temperature of the SC cut crystal so it is sitting right at the knee of the Tempco. This gives an oscillator with a very low Tempco, very low aging and very low phase noise. Not all OCXOs are created equal, in particular the less expensive OCXOs (say less than $100) do not use a crystal and circuit with particularly low phase noise, but they DO have very low Tempco and low aging, but the phase noise is no better than a $10 regular crystal oscillator. Again this is just a waste of money, you are spending money on something that doesn't make sound better. (note this is "new" price, not what you can get on ebay for a used one). BUT if you spend the money on a very special SC cut crystal and very special circuitry you can get the lowest phase noise of any oscillator known. It is not cheap, but this type of OCXO IS the way to get the lowest phase noise. OCXOs at this level also give you very low aging and very low Tempco, but these are not primarily the main reason for getting one of these OCXOs. Unfortunately for audio, most applications (other than audio) want very good specs for ALL the parameters, it should be possible for the manufacturers to optimize for phase noise only, thus giving us lower cost oscillators since they are not trying get say extremely low aging. One other VERY important aspect about phase noise: comparing charts can ONLY be done if the frequencies are the same. The phase noise for an oscillator increacess by 6dBc/root Hz per octave of the oscillator frequency. Thus of you have plot for a 10 MHz oscillator and one for the same model oscillator at 20 MHz, the numbers will be 6 dBc/ root Hz higher. If you take that 20 MHz output and run it through a good flip flop, dividing the frequency by two, you will get the same phase noise plot as the 10MHz version. So be VERY careful when comparing phase noise from different oscillators , they either need to be at the same frequency or you apply the 6 dBc/ root Hz rule. (explaining that rule is a little complicated so just take my word for it) Sooo as far as aging is concerned, spec sheet aging has nothing to do with audio. John S. Thanks a lot John for all your insights! While I'm personally an audio engineer by trade, my focus at MUTEC is marketing so I'm by no means on the same level of technical understanding as you are when it comes to OCXOs and phase noise. That said, I had the chance to discuss the matter with MUTEC's chief oscillator guru and I think it's safe to say that we agree on pretty much all counts. I'm adding his responses to some sub-questions of various folks inline below: On 8/29/2018 at 8:08 PM, str-1 said: I yesterday posted this question on the "A novel way to..." thread but then remembered this thread which I had read through part of last year, so thought I would post here as well. It's about the aging of the crystals these reference clocks use. How long under normal use would it be before I might expect to hear an aging crystal's contribution to a dropping off of performance from a Mutec REF 10 (or any other similarly specified reference clock)? The aging figures quoted for the REF 10 and for other clocks I have looked at indicate very, very small deteriorations under normal use. But can the aging process be accelerated by persistently adverse environmental factors, such as the increased heat from stacked and poorly ventilated equipment arrangements, or week on week of 30C degree summer heat in London where domestic air-conditioning is the exception rather than the rule? I could also mention variation in power supply, but would do so accepting that Mutec and other clock manufacturers have taken steps to ensure that that should not be an issue. I am interested in this because the benefits of using a reference clock with their equipment reported by many on CA and other forums range from the subtle to the profound, and I find myself wondering if I were to buy a REF 10 and found the benefits to be subtle, how long it would be before I lost even that due to deterioration of the crystal (accepting that other components would also degrade over time). First of all, the ambient temperature doesn't affect the aging of the OCXO because the crystal is operated at a much higher temperature. So this is not something to worry about. As John also pointed out the absolute frequency of the OCXO doesn't affect the phase noise and hence the audio performance. There is a small age-related drift that occurs, but it's a non-issue. Theoretically you could compensate for this drift with a super precise time-reference such as a GPS or atomic reference, but again, it's not necessary. The age-related frequency drift typically follows an asymptotic curve, meaning that it gets smaller over time. So as the crystal gets older, the rate of frequency change get lower and lower. After just a few years, the rate of change is then typically lower than the original spec for the fresh oscillator. On 9/1/2018 at 9:12 AM, Confused said: An interesting question regarding aging from @str-1 One thing that has been mentioned in this thread a number of times is that absolute clock accuracy (over time) is not important for an audio clock, what is important is the phase noise, something for which the REF10 has very impressive specifications. So this begs a question, from the specs the phase noise of the REF10 at, say, 10 Hz is less than -145dBc/Hz. So what happens to this figure after +/- 0.2 ppm aging after 10 years? OK, the figures are there, but I do not have a clue as to how significant this is in practice. OK - let's assume there is some unwanted degradation of performance over time. This then begs a second question, how best to mitigate this? To take my own use of the REF10 as an example. I know there is a warm-up time to achieve optimum clock stability, so I simply leave mine powered up and running 24/7, also, I am sure that powering up / down must cause some aging. However, in a typical week for me, the system may not be used between Monday morning and Friday evening. So some weeks, I could turn the REF10 off on Sunday night and then power it up again for the weekend on Friday evening. Over the year, this would mean the unit is powered up / down maybe 50 times, which in itself may cause degradation, but on the other hand, I would save maybe 6000 hours running per year. So which causes the most aging, 50 power cycles per year, or 6000 hours running per year? This might seem a bit of an obsessive question, but it would be easy enough for me to use the REF10 either way, and if one way was better for design life than the other, then that is the way I would go. Why not? I suspect that there would be very little in it either way, but it would be good to know. On the two points above, I would be very grateful if @julian.david could provide some insight. You can argue that the frequent changes in temperature that the components of a device like the REF 10 are exposed to due to frequent power cycles accelerate the aging process. This would mean that it's better to leave the device powered up. At the same time though, the life cycle of the electrolytic capacitors are finite, which then would suggest it's better to turn it off for longer breaks. But in the case of the REF 10 the electrolytic caps are operated at temperatures much below than the temperatures used to estimate their life cycles so this also shouldn't be an issue in any reasonable time frame. So in general, our recommendation would be to leave the REF 10 on except for very long breaks like a whole week as @Confused is mentioning. By the way, drifts in the power grid voltage are a non-issue because they get compensated by the internal power regulation of the REF 10 and won't affect the audio performance. Generally, the power supply of the REF 10 has been designed very conservatively so that the critical components don't get too hot even on warm days and when the REF 10 is mounted within a rack. That is at least as long as the housing vents are not blocked and proper air circulation is ensured. Hope this all helps! Julian auricgoldfinger, str-1, Confused and 3 others 3 3 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
str-1 Posted September 10, 2018 Share Posted September 10, 2018 On 8/31/2018 at 7:32 AM, baconbrain said: Certainly not an expert on this, but I believe the influence of external factors to the rate of deterioration must be a given. The question I would have back to you is: If the amount of benefit from the Ref10 is so subtle that one is concerned about a rate of deterioration +/-0.2 ppm (over 10 years), then is the total investment (Ref10 + cables + ....) warranted to begin with? Thanks @julian.davidand @JohnSwenson. Awesome answers. It was just idle curiosity when I first raised the question of aging but glad the matter has now well and truly been put to bed. Zenith SE > USPCB (5v off) > tX-USBultra 9V (SR4) > Sablon Reserva Elite USB > M Scaler > WAVE Stream bnc > DAVE > Prion4/Lazuli Reference > Utopia/LCD-4/HE1000se Link to comment
Confused Posted September 10, 2018 Share Posted September 10, 2018 1 hour ago, julian.david said: It's something we're still looking into, but progress has been a little slow because we're currently focused on a much bigger, and (I think) more exciting project... I'll let you know as soon as there's news on the cable front though. Julian A bigger and more exciting project? Interesting, I have to say that I have thought for a while that the REF10 looks a little lonely as the only product in Mutec's "Empyreal Class" category, is the REF10 going to get some Empyreal Class company? For me, an Empyreal Class version of the MC3+USB would be most excellent. I know that I am being slightly mischievous here, I am sure that if you could say more in the short term you would, and that when you are ready to say something, I am sure you will. Meanwhile, it's fun to speculate.? Anyway, many thanks for the feedback on the other points regarding aging etc., very much appreciated. Thanks also to @JohnSwenson, great stuff as always. Windows 11 PC, Roon, HQPlayer, Focus Fidelity convolutions, iFi Zen Stream, Paul Hynes SR4, Mutec REF10, Mutec MC3+USB, Devialet 1000Pro, KEF Blade. Plus Pro-Ject Signature 12 TT for playing my 'legacy' vinyl collection. Desktop system; RME ADI-2 DAC fs, Meze Empyrean headphones. Link to comment
andresz Posted September 10, 2018 Share Posted September 10, 2018 Thanks Julian - I put a few posts in various forums and found a happy user of a Nvidia with Mutec USB 3+. All works fine. Great news as I have been wanting to buy a unit but a bit worried re compatibility. Thx for the response! julian.david 1 Link to comment
jabbr Posted September 10, 2018 Share Posted September 10, 2018 12 hours ago, JohnSwenson said: it should be possible for the manufacturers to optimize for phase noise only, thus giving us lower cost oscillators since they are not trying get say extremely low aging. Q and look at the cut, not “OXCO” 12 hours ago, JohnSwenson said: One other VERY important aspect about phase noise: comparing charts can ONLY be done if the frequencies are the same. The phase noise for an oscillator increacess by 6dBc/root Hz per octave of the oscillator frequency. Thus of you have plot for a 10 MHz oscillator and one for the same model oscillator at 20 MHz, the numbers will be 6 dBc/ root Hz higher. If you take that 20 MHz output and run it through a good flip flop, dividing the frequency by two, you will get the same phase noise plot as the 10MHz version. Excellent point! Custom room treatments for headphone users. Link to comment
baconbrain Posted September 11, 2018 Share Posted September 11, 2018 23 hours ago, julian.david said: It's something we're still looking into, but progress has been a little slow because we're currently focused on a much bigger, and (I think) more exciting project... I'll let you know as soon as there's news on the cable front though. Julian I would be curious to know if the new project / product will be released in the near (next 90 days) or distant future? ? Link to comment
justubes Posted September 11, 2018 Share Posted September 11, 2018 Julian, If the Ref is used to reference any device or specifically a normal vcxo, how much does it contribute to the lower phase noise of the master? So will a Ref 10 refencing a mc3+USB, it there any further improvement or benefit of having a better or even lower phase noise osc in the mc3+ usb? Link to comment
julian.david Posted September 11, 2018 Share Posted September 11, 2018 10 hours ago, baconbrain said: I would be curious to know if the new project / product will be released in the near (next 90 days) or distant future? ? It's not going to be in the next 90 days and then we're hitting Christmas time, so let's say we're shooting for early 2019. But let me also say that any major roadblock could easily set us back. You guys here will definitely be among the first to learn about it. Confused 1 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
julian.david Posted September 11, 2018 Share Posted September 11, 2018 3 hours ago, justubes said: Julian, If the Ref is used to reference any device or specifically a normal vcxo, how much does it contribute to the lower phase noise of the master? So will a Ref 10 refencing a mc3+USB, it there any further improvement or benefit of having a better or even lower phase noise osc in the mc3+ usb? Hi, I'm not quite sure I fully understand your question. If it is whether or not the REF 10 can improve the MC-3+USB then the answer is yes, absolutely. That's what the external re-clock mode in the MC-3+USB is for and one of the reasons we even made the REF 10. In fact, our trade show demo system has in the past consisted of an MC-3+USB playing back audio from Roon on a laptop to a headphone DAC. As part of the demo we would switch from re-clocking based on the internal clock of the MC-3+USB to the external clock reference from the REF 10. The effects could be quite easily discerned by booth visitors despite the pretty noisy show floor. Does that answer your question or did I somehow misinterpret it? Julian MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
rickca Posted September 11, 2018 Share Posted September 11, 2018 @julian.david I think the question is this ... if you're using a REF10 into an MC-3+ USB, would there be any benefit to having a better (lower phase noise) clock in the MC-3+ USB than the one in the current product? I guess the speculation is that an Empyreal class version of the MC-3+ USB might have a better clock than the current product. Pareto Audio AMD 7700 Server --> Berkeley Alpha USB --> Jeff Rowland Aeris --> Jeff Rowland 625 S2 --> Focal Utopia 3 Diablos with 2 x Focal Electra SW 1000 BE subs i7-6700K/Windows 10 --> EVGA Nu Audio Card --> Focal CMS50's Link to comment
Popular Post julian.david Posted September 11, 2018 Popular Post Share Posted September 11, 2018 2 minutes ago, rickca said: @julian.david I think the question is this ... if you're using a REF10 into an MC-3+ USB, would there be any benefit to having a better (lower phase noise) clock in the MC-3+ USB than the one in the current product? I guess the speculation is that an Empyreal class version of the MC-3+ USB might have a better clock than the current product. Ah ok, I get your point now. Well, the clock is more than just a crystal so implementing a more sophisticated clock in the MC-3+USB is pretty involved. You have to look at all the components involved including the power supply. So at that point it's a complete re-design pretty much from scratch. If we did that as an Empyreal Class product, then that would cannibalize a lot of the appeal of the REF 10 as an upgrade option for an MC-3+USB. I can't lay out MUTEC's entire product strategy here, but we're very happy with the performance of the MC-3+USB as is, especially when combined with the REF 10. mourip and Confused 1 1 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
justubes Posted September 12, 2018 Share Posted September 12, 2018 Yes I understand in a product implementation that will increase the cost and make lines finer between theproduct lines. Just for further understanding and discussion. Suppose the base of the mc3+usb has a even lower phase noise clocking, closer to that of the Ref 10, this would surely increase the cost a fair bit to also get a better power supply into a larger unit. The question is even if still fed by the Ref 10 Which still has a better phase noise. How much does this external reference contribute to the overall phase noise in comparison to the mc3+ usb now as it is vs. Fitted with an even better oscillator. Is the determining factor more so the internal oscillator in the mc3+usb or will the better external reference still be the dominant and determining factor of the low phase noise in the mc3+ usb? If we rate. In a scale of 100% and take the base of the Ref 10 as 100 for low phase noise in clocking scoring Ref 10= 100 (base, best clock> Mc3+USB = 80 MC3+ USB plus ref 10 =90 MC3+ with improved oscillator over current 10g clocking plus the Ref 10 =?? Will there be yet another nice jump to say a score of 95 or will the score still be similar to 90, since the Ref 10 is disciplining the MC3+usb? Link to comment
Popular Post julian.david Posted September 12, 2018 Popular Post Share Posted September 12, 2018 7 hours ago, justubes said: Yes I understand in a product implementation that will increase the cost and make lines finer between theproduct lines. Just for further understanding and discussion. Suppose the base of the mc3+usb has a even lower phase noise clocking, closer to that of the Ref 10, this would surely increase the cost a fair bit to also get a better power supply into a larger unit. The question is even if still fed by the Ref 10 Which still has a better phase noise. How much does this external reference contribute to the overall phase noise in comparison to the mc3+ usb now as it is vs. Fitted with an even better oscillator. Is the determining factor more so the internal oscillator in the mc3+usb or will the better external reference still be the dominant and determining factor of the low phase noise in the mc3+ usb? If we rate. In a scale of 100% and take the base of the Ref 10 as 100 for low phase noise in clocking scoring Ref 10= 100 (base, best clock> Mc3+USB = 80 MC3+ USB plus ref 10 =90 MC3+ with improved oscillator over current 10g clocking plus the Ref 10 =?? Will there be yet another nice jump to say a score of 95 or will the score still be similar to 90, since the Ref 10 is disciplining the MC3+usb? I can't really give you answers to all those very specific technical questions, but I also think you're imaging the design process to be simpler than it really is. There is not a single parameter or value you can look at to rate the performance. As John already pointed out, you have to look at the phase noise as a function of the offset from the carrier in the graph. Tweaking one parameter may cause another parameter to change. More often than not product design (at least in my experience) is a matter of compromise and weighing pros and cons. The MC-3+USB is also a pretty diverse product with clock generation and distribution, re-clocking, and USB-interface components. I don't even know if an objective internal phase noise performance increase would have the same effect on all these components, but I'm sure Christian Peters has looked into that. At the end of the day though, just because something looks good on paper, still doesn't tell you if it actually sounds good. The challenging, but also fascinating part in audio product design is that you have the technical evaluation and the listening tests that you have to somehow reconcile to come up with a great product. Superdad and mourip 1 1 MUTEC GmbH Marketing Associate Email [email protected] Web www.mutec-net.com Link to comment
LowMidHigh Posted October 11, 2018 Share Posted October 11, 2018 I made a point in reference to REF10 (pan not intended) in a different thread, comparing it to the upgraded Cybershaft, and Julian suggested I move it here. Here's his reply: Hi there, While it’s true that some of Cybershaft’s latest 10 MHz clocks match the phase noise performance of the REF 10 at 1 Hz offset at a lower price, I think it’s also worth pointing out that these OCXOs are used, recycled oscillators with potentially questionable long-term performance. This is no secret as Cybershaft themselves note it in the fine print of these product pages. We’ve been doing quite a bit of research in this field at MUTEC prior to the launch of the REF 10. Our main developer has inside knowledge of the second-hand oscillator market and how these oscillators are handled in the process. So for us at MUTEC there were and still are a lot of reasons why we stay away from these predominantly Chinese-sourced recycled OCXOs. Sure, there’s a 2-year warranty but a performance decay and functional unreliability may easily slip in unnoticed over time. Buying a REF 10 guarantees a brand-new, carefully tested German-made OCXO that will provide excellent performance for many years to come. I personally believe there’s a real value in having the peace of mind that your newly bought equipment performs at its peak. But ultimately the great thing about competition is that everybody can make those decision on their own depending on their preference and budget. BTW, this discussion is probably better suited to take place in the REF 10 thread but I still thought it'd be worth chiming in here. Hope this helps, Julian Stereo [Genelec 1032C x 2 + 7360 x 2] <== [MC3+USB x 3 <-- REF10 SE120] <== [AERIS G2] <== [EtherRegen x 3] Chain switchable to [Genelec 8331 x 2 + 7350] Surround [Genelec 1032C x 3 + 8431 x 2 + 7360 x 2] <== [MiniDSP U-DIO8] <== [Mac Mini] Link to comment
LowMidHigh Posted October 11, 2018 Share Posted October 11, 2018 You make very compelling points, Julian. Thank you. Since I’m in the market, I’d like to ask a few public questions that might be to the benefit on others: Your literature mentions the square signal and steel chassis as contributing factors to the REF10 performance. How influential are they? Crudely speaking, 5%, 10%? How many years for continuous use can one expect from the REF10? Roughly of course. Is there a point in time in which a re-calibration is in order? Is that a service Mutec offers? How far apart can I place the REF10 from the slave? I have 2 systems that could benefit from the REF10. One would demand a 14-meter word clock cable, though… Thanks in advance! Johnseye 1 Stereo [Genelec 1032C x 2 + 7360 x 2] <== [MC3+USB x 3 <-- REF10 SE120] <== [AERIS G2] <== [EtherRegen x 3] Chain switchable to [Genelec 8331 x 2 + 7350] Surround [Genelec 1032C x 3 + 8431 x 2 + 7360 x 2] <== [MiniDSP U-DIO8] <== [Mac Mini] Link to comment
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now