View Full Version : Superclock in SL-1210
Has anyone thought of replacing the 4.19328MHz crystal X201 feeding pin 5 of IC201 with a superclock, say one of Audiocom's ones? I'm toying with the idea but unsure whether that is a common frequency and whether it would work in that circuit. If not possible, what about a higher quality more accurate crystal?
Any ideas?
WOStantonCS100
17-01-2012, 21:14
I've been looking into this ever since reading about the Inspire Monarch. There has to be a source; just have to track it down.
Wakefield Turntables
17-01-2012, 21:55
MMmmmmm would be interesting to see what Paul has to say about this, yet another possible mod to add to the list
Reid Malenfant
17-01-2012, 21:59
You'd probably need to get a custom quartz crystal made as it's a non common frequency. I doubt you'd be able to find anything close & trim it's frequency & still maintain the stability of a superclock. Dividing down from a higher frequency may well be possible, so look for multiples of the fundamental.
Google is your friend ;)
WOStantonCS100
18-01-2012, 05:26
If we know what to ask for, perhaps these folks would make a batch of them for us??
http://www.bomarcrystal.com
The question is, Biff, would a replacement crystal be any better than the one used by Panasonic?
I'd love to get Audiocom's views. Where's Mark Bartlett?
prestonchipfryer
18-01-2012, 07:07
If a crystal could be sourced, how easy/difficult to implement on the sl12** would that be?
John :)
As easy as removing the original and soldering in the replacement.
I'm watching this one with interest, as the 'improved' crystal used in the Monarch was one of the reasons given why it apparently sounded so good!
Although until one of us with a heavily modded Techy compares it to our own T/T, we've no idea whether that 'good' is better or not than the good (more like awesome) we already get...............
Marco.
sq225917
18-01-2012, 09:45
Marco, exactly.... We all know how prone hifi mags are to largess, I'd love to hear one, maybe we could arrange one from Bob, he's just 2 miles up the road from me.
Lol, perhaps - that would certainly be interesting and no doubt entertaining! ;)
I think we have to remain open minded to the possibility that current technology may have succeeded to produce a more advanced and sonically superior crystal to that which Panasonic originally used.
However, we must also acknowledge that the crystal Panasonic used would've been an integral part of the original circuit, and that a turntable is very much about the sum of its parts, rather than the influence of any individual component.
Marco.
One thing's for sure: that crystal frequency seems to be unique to the SL-1210, I can't find one of that frequency from anywhere else. Would be interesting to take a dekko at Monarch's improvements. Maybe they have put it in a temperature controlled environment? Easy to put it in a small can with a resistor to create a constant temperature.
Reid Malenfant
18-01-2012, 13:34
If you want the best you need one with a built in oven :) I know that sounds nuts, but effectively the idea is to keep the crystal at a dead constant temperature & thus the accuracy will be maintained over various room & equipment temps.
It's not really an oven but effectively a small heater, probably a resistor & a temperature sensor designed to keep it at a set temp.
Not sure what's in these superclocks but I know they are more accurate than the common or garden quartz crystals in standard players, they maintain the accuracy as well from what I have read :)
E2A:- :doh: Should have read Martins post :rfl:
Failing any other avenue, I might try the 'oven' approach.
Paul Hynes
18-01-2012, 17:20
I will be ordering some crystals shortly for a new clock design that I have running in test. I will ask the manufacturer if he can produce a suitable crystal for the SL1200.
Thanks, Paul! Meanwhile, I am in discussion with Mark at Audiocom with a view to whether a Superclock could be applied to the circuit.
Wakefield Turntables
18-01-2012, 18:27
Great idea with regards the Superclock. I always suspected the PCB and components could be bettered. I'm watching this thread with great interest.
WOStantonCS100
18-01-2012, 19:32
I will be ordering some crystals shortly for a new clock design that I have running in test. I will ask the manufacturer if he can produce a suitable crystal for the SL1200.
Yes, awesome! As well, thank you, sir! I look forward to the response.
Great idea with regards the Superclock. I always suspected the PCB and components could be bettered. I'm watching this thread with great interest.
+1
sq225917
18-01-2012, 23:32
Looking at something similar for the Hercules PS, new discrete regs and better XO's/local regs. Has to be worth a tinker, and I'll measure the results at the stylus for you all to see.
If you are going to build an ovenized oscillator, you must use a crystal that is designed to work in an oven. They usually are not cheap.
"Cheap" crystals are usually in an HC-49/s holder. You could not pay me to use one of those. If you are going to get someone to make you a custom crystal, don't let them talk you into that holder. It will not be any better than what you already have. It very well could be worse.
Crystals are manufactured to be inexpensive, just like pretty much anything else. It is just a fact of life. But, getting someone to make a decent one is not fun. They are all geared to buying their parts from Asia, and their sole concern is price. Few companies make their own crystals, these days. So, when you approach someone about making a custom part, they usually are not interested. Their suppliers only want to make parts that are cheap and common. Trying to get someone to make a small handful, at an oddball frequency, is a pain.
We have been beating the bushes, for months, trying to get decent crystals. And at the usual frequencies, for digital audio.
Good luck!
Thanks - that's good, if sobering, information to have.
sq225917
20-01-2012, 09:39
See if Guido Tent has any suggestions he seems to be able to source a variety of do an tcxo's for his own tentlabs stuff.
Paul Hynes
20-01-2012, 10:54
I will bear that in mind when sourcing my own crystals.
Few companies make their own crystals, these days. So, when you approach someone about making a custom part, they usually are not interested. Their suppliers only want to make parts that are cheap and common. Trying to get someone to make a small handful, at an oddball frequency, is a pain.
And that's exactly what pisses me off about audio these days: it's all about quantity over quality, driven by the bottom line! :rolleyes:
Is it therefore any wonder why many of us build our systems around quality vintage equipment, designed in an era when overall standards were much higher? Whatever happened to striving for excellence, genuine innovation, and creating something that is truly unique and special??
To my huge disdain, we've largely become an undiscerning nation of mindless sheep, who are easily dictated to and satisfied with blandness and mediocrity. And they call this progress!!! :doh:
Marco.
Reid Malenfant
20-01-2012, 14:54
Ok guys, I have just had a thought :)
If getting an ovenized cystal is going to be problematic it might be worth considering simply keeping the standard crystal at precisely the right temperature to produce exactly the right frequency.
It wouldn't be too difficult to use a peltier cooler to maintain an exact temperature. They work both ways, with DC current fed one way one side heats up & the other cools, feed DC in the opposite polarity & the side that heated up previously cools & vice versa.
Shouldn't be difficult to make a control circuit to do the job :)
My thinking says that the exact frequency is not so important (certainly not the highest priority as it is for radio operators), it's the stability and jitter that are critical. Will any kind of temperature controlled enviroment improve that, or is it down to how optimally the flip-flop circuit uses the crystal? This I think is where the Superclock comes in.
Ok, the first thing you guys need to decide is what exactly it is that you want to accomplish, and why.
I know..........."I want it to sound better!"
Right. And what parameter(s) make it "better". Stability? Sort-term, or long-term? Phase noise?
Once you know the answer to those, and why, then you can think about making it "better".
If "better" is long-term stability, then what you have may be good enough. Short-term..........??? Phase noise.......I can promise you it isn't. (And I don't even know what you have, what it does, and how it is made.)
OK......someone said jitter, etc. Yes, if you divide down, the jitter gets better. But, the higher the reference, the harder it is to get a good crystal. And therefore, low jitter.
If whatever this thing is already has a divider chain, then it probably will not get any better. Eventually you hit the real-world noise floor, and that is as low as you can go. Divide any clock enough times, and that is what you get.
sq225917
21-01-2012, 08:28
There is a divider chain on both the 1210 and the Hercules board I'll be using. To be honest I'm more interested in psu quality and splitting each stage than I am about the quality of the do reference. Crystal effects will be swamped by motor cogging in the 1210 and by cogging and belt incOnsistencies in my application.
It can't hurt though, can it? I think most of us just like fiddling with stuff. I actually give away far more stuff than I build for myself.
What I want is not long term stability (which will have precious little effect on sound quality), I want jitter reduction to give the cleanest clock possible. Some of that will come with the phase 3 regs I'm about to install, to give the AN6680 control IC a cleaner supply, and some of it could come from a Superclock circuit.
In the case of the Technics, jitter reduction could help reduce rotational noise amplified and fed into the motor by the AN6675 motor drive IC.
I think knowing what the time constant of the speed control loop is, in relation the the frequency used in the digital circuit would help to understand if jitter is a significant factor.
If for instance the crystal oscillates at 4 Mhz, but the control loop operates at 100hz, the jitter noise may not even be discernible to the control loop.
I'm a mech engineer, not an EE, but that is what comes to mind.
Exactly!!!!!!!!!!!!
The phase noise of the reference will be reduced by 20*log N, where N is the integer division rate. If the division ratio is 1000 (servo running at 400 Hz), you have picked up 80 dB of noise reduction. You are now into the noise floor.
5 PPM of short-term drift might be 20 Hz, at 4 MHz. But it is now 0.002 Hz, at 400 Hz. Do you think you will hear that much speed variation?
sq225917
21-01-2012, 16:56
I guess it depends on the pattern of error, entirely random error at such a low level is going to be inaudible but if you up the level a little and find out the error is modulated by something else on the board then it'll become audible much sooner than one might expect.
I know having worked through the circuit on my Hercules board that I'm better spending my time working the power supply for the transistors that drive the two sine waves than I am wasting money on better XO or power supplies for the XO.
We know from CD player upgrades that clock stability is critical to good sound. My old Sony SCD-1 flagship SACD player had battleship construction, quality PCBs and compartmentalised shielding. However, a Superclock 2 from Audiocom certainly made a considerable difference in both CD and SACD replay.
The jitter reductions may be small but they are audible. I know that the above is clocking data and for the Techie we are talking about rotational noise. I'm not saying I know there will be an improvement: I'm saying I want to try it.
Martin,
Many upgrades accepted today, were ridiculed at the time as not possibly being capable of making a difference. I say go for it! It couldn't hurt to try and see what happens.
We know from CD player upgrades that clock stability is critical to good sound. My old Sony SCD-1 flagship SACD player had battleship construction, quality PCBs and compartmentalised shielding. However, a Superclock 2 from Audiocom certainly made a considerable difference in both CD and SACD replay.
The jitter reductions may be small but they are audible. I know that the above is clocking data and for the Techie we are talking about rotational noise. I'm not saying I know there will be an improvement: I'm saying I want to try it.
You can not equate the amount of jitter, in your CDP, to the amount of jitter one will have, after it is run through a divider chain.
1.) You are not going to find a crystal at that frequency.
2.) You will not be able to measure any change in jitter/phase noise. Not only because you do not have the gear (it costs many thousands of dollars), but because it is going to be in the noise level.
3.) Your money..........and what do I know............enjoy!
Over and out.
Paul Hynes
22-01-2012, 13:21
I seem to recall someone telling me that regulators that were designed to operate up to 100 MHz for digital circuitry were a waste of time as at these frequencies the type and position of capacitors in the circuit power lines were the important issue. The capacitors are important but so is the regulator. I have sold thousands of these regulators, so far, with a 56 day return if not satisfied guarantee. I think people are pleased with the improvements these regulators have made, as they are not being returned. If they were making no improvements I would have a very large box full of rejects by now.
Several of my friends over the years have shown the ability to discern perfect pitch just by listening to a note. They could tell if the note was off pitch by small amounts. In the past our survival in the wild was based on a keen sense of sight and hearing. Being able to judge distance and direction accurately could mean the difference between life, or death, at the hands of a predator. The human brain is a very complex organ that is capable of processing sensory input in a way that focuses on important data and ignores unimportant data. Many have reported hearing signal events buried in the noise floor.
There are plenty of examples of audio equipment with exemplary measurements that do not convey music in a comprehensible way. On balance I will take what I hear over measurements every time.
Regards
Paul
On balance I will take what I hear over measurements every time.
Indeed, Paul, and yet you are an engineer. As I have said to many others over the years, there is no conflict of interest!
Paul Hynes
22-01-2012, 14:28
There should not be a conflict of interest but I think you will be saying this to many more over the coming years.
I seem to recall someone telling me that regulators that were designed to operate up to 100 MHz for digital circuitry were a waste of time as at these frequencies the type and position of capacitors in the circuit power lines were the important issue. The capacitors are important but so is the regulator. I have sold thousands of these regulators, so far, with a 56 day return if not satisfied guarantee. I think people are pleased with the improvements these regulators have made, as they are not being returned. If they were making no improvements I would have a very large box full of rejects by now.
Several of my friends over the years have shown the ability to discern perfect pitch just by listening to a note. They could tell if the note was off pitch by small amounts. In the past our survival in the wild was based on a keen sense of sight and hearing. Being able to judge distance and direction accurately could mean the difference between life, or death, at the hands of a predator. The human brain is a very complex organ that is capable of processing sensory input in a way that focuses on important data and ignores unimportant data. Many have reported hearing signal events buried in the noise floor.
There are plenty of examples of audio equipment with exemplary measurements that do not convey music in a comprehensible way. On balance I will take what I hear over measurements every time.
Bloody hell - what an amazing post!!! :eek: :respect:
I concur completely :clap: :clap:
It's going right into Our Ethos for permanent reference!
Marco.
I seem to recall someone telling me that regulators that were designed to operate up to 100 MHz for digital circuitry were a waste of time as at these frequencies the type and position of capacitors in the circuit power lines were the important issue.
They did? Don't they realize regulators don't work at 100MHz? Yeah, that is why the caps are needed. But regulators regulate, and caps bypass. Both are important, but have much different jobs.
I bet they also think all caps are the same, because it is 100 MHz. Or any other frequency, as well. Oh, well........
Anyway, back to the original issue.........
Guys, I am probably the only person any of you will run into that has experience designing low-jitter oscillators. If sticking a different crystal into a circuit was all it took, anyone could do it. But, it is far more complicated than that.
Most crystals perform about the same, because they are all made about the same. And that is: cheap.
To get any less phase noise (jitter) than you already have, it will cost $$$. You can not, or will not, get a "typical" crystal that will perform any better. Even if you called up someone, like IQD (in your neck of the woods), they are not going to budge unless you start to talk about making thousands. If you do find someone who will make a one-off, without a large minimum, or price tag, what do you think they will sell you?
"Why don't you want a HC-49/s? What is wrong with them? That is what everyone uses these days."
(At this point, you know you are talking to a salesman, and you might as well talk to the wall.)
Just like pretty much everything else, these days, crystals have been relegated to "commodity" status. Which means no one makes their own, as they outsource to Asian suppliers. Which is why they are all cheap, and perform that way.
In fact, I will stick my neck out further, without even seeing what is inside your TT, and go as far as to say if you do get a "new" crystal that it will be worse, than what you have.
Guessing what era that TT was made, I will wager it uses a HC-49 holder. Which is the typical holder used in commercial electronics, back then. They are ok. Biggest flaw is it is a resistance-weld holder. Which is going to limit performance, as it will not be as clean (internally) as one would need, for really good performance.
And you are going to step down, to a HC-49/s.
I am sure there is 1000 things you can do, to improve your TT. Changing the crystal is not one of them.
WOStantonCS100
23-01-2012, 05:13
Anyway, back to the original issue.........
Guys, I am probably the only person any of you will run into that has experience designing low-jitter oscillators. If sticking a different crystal into a circuit was all it took, anyone could do it. But, it is far more complicated than that.
Most crystals perform about the same, because they are all made about the same. And that is: cheap.
To get any less phase noise (jitter) than you already have, it will cost $$$. You can not, or will not, get a "typical" crystal that will perform any better. Even if you called up someone, like IQD (in your neck of the woods), they are not going to budge unless you start to talk about making thousands. If you do find someone who will make a one-off, without a large minimum, or price tag, what do you think they will sell you?
"Why don't you want a HC-49/s? What is wrong with them? That is what everyone uses these days."
(At this point, you know you are talking to a salesman, and you might as well talk to the wall.)
Just like pretty much everything else, these days, crystals have been relegated to "commodity" status. Which means no one makes their own, as they outsource to Asian suppliers. Which is why they are all cheap, and perform that way.
In fact, I will stick my neck out further, without even seeing what is inside your TT, and go as far as to say if you do get a "new" crystal that it will be worse, than what you have.
Guessing what era that TT was made, I will wager it uses a HC-49 holder. Which is the typical holder used in commercial electronics, back then. They are ok. Biggest flaw is it is a resistance-weld holder. Which is going to limit performance, as it will not be as clean (internally) as one would need, for really good performance.
And you are going to step down, to a HC-49/s.
I am sure there is 1000 things you can do, to improve your TT. Changing the crystal is not one of them.
If what you say about sourcing crystals is true, then I have a big question for Inspire about their Monarch turntables. They say, "...such as a new
quartz chip of greater spec..." So, either someone has already done what you say only has a slim chance of being possible or the Inspire folks aren't being honest. I would love to know which one it is.
I am sure there is 1000 things you can do, to improve your TT. Changing the crystal is not one of them.
Thank you Patrick, that's very useful information. The crystal type as far as I can see is a HC49 low profile can.
So, if we assume for the moment that the crystal cannot be improved upon, we are left with two scenarios:
1) Lift the crystal from the PCB and make a temperature controlled environment for it, say between 40-60C.
2) Lift the crystal from the PCB and put it into a better/more stable oscillator circuit.
The question is, will either of these give us lower jitter than the crystal in the AN6680 circuit fed with a very clean power rail?
If what you say about sourcing crystals is true, then I have a big question for Inspire about their Monarch turntables. They say, "...such as a new
quartz chip of greater spec..." So, either someone has already done what you say only has a slim chance of being possible or the Inspire folks aren't being honest. I would love to know which one it is.
Me too, Biff!! Any view on this, Partick?
Here's a pdf of the review where the crystal upgrade is mentioned: http://www.inspirehifi.co.uk/inspirehifi/monarch_files/HFW_Inspire%20Monarch%20Jan12%5B1%5D.pdf
The onboard circuitry is upgraded with high-spec parts such as a new quartz chip of greater spec – taking speed control to even greater heights than previously achieved with past Technics, it is claimed.
???
Marco.
sq225917
23-01-2012, 10:13
That's an obvious and demonstrable claim, most simple Xo come in one of two specs, 30ppm or 20ppm, other than that you really would be specifying an uber part in a oven and a decent tcxo is going to cost a lot more than Bob could afford to put in that deck. The simple way to find out is to look at the part currently in the 1210, if it's the 30ppm piece then It can be improved, if it's a 20ppm then it really can't.
I view all such 'marketing' claims with healthy skepticism. I'm with ART on this one.
Sorry, Simon, for the benefit of the non-technical minded, could you please explain (in 'layman' terms) what an "Xo" is, and what "30ppm or 20ppm" are, and what sonic influence each would have?
Also, would the sonic advantages between 30ppm or 20ppm be roughly equipvalent to what a "decent tcxo" would do (and if not, why?) - oh, and while you're at it, what exactly is a "decent tcxo"? ;)
Churz! :cool:
Marco.
sq225917
23-01-2012, 11:49
20 parts per million: a measure of accuracy. Xo are generally specced for noise and drift. The difference between 20 and 30 ppm will be utterly inaudible, but as technical claims go 20ppm is 'better' than 30.
Xo oscillator
Vcxo voltage controlled.
Tcxo temperature controlled- ie in a regulated oven.
Paul Hynes
23-01-2012, 12:11
Pat,
Your comments regarding sourcing crystals, and their use, is helpful. Industry is slowly taking us all down to the lowest common denominator. Fortunately there are still those who are dedicated to making things better.
Perhaps you would care it illuminate us as to why you think there are no regulators capable or regulation up to 100 MHz.
Regards
Paul
Thanks, Simon :)
Xo are generally specced for noise and drift. The difference between 20 and 30 ppm will be utterly inaudible, but as technical claims go 20ppm is 'better' than 30.
So if that's the case, and as you say likely what Inspire have 'improved' in the new crystal that they're using, it's not going to account for any huge improvement in sound.... Is it? Therefore, whatever is making the Monarch sound so good (as per the reviews), if you are right, obviously isn't the new crystal.
The only way to achieve a genuine upgrade in that area, it would seem, is to have a top-notch bespoke crystal designed, as Partick has outlined. And based on what he's said, that ain't going to happen anytime soon!
What needs to be done, so that we're dealing in facts, not fiction, is for the crystals used in both the Monarch and the Techy to be identified, and that information reported here. Who's up for that job, then?
Marco.
sq225917
23-01-2012, 14:45
Marco, the crystal is divided down so far it's likely to make 0.0000000001% difference of the square root of f_ck all. It's a specious claim at best. What we really need is a demo- heads up, back to back. ;-)
So much of the 1210 sound is in the mechanical parts and their mounting.
Marco, the crystal is divided down so far it's likely to make 0.0000000001% difference of the square root of f_ck all. It's a specious claim at best. What we really need is a demo- heads up, back to back. ;-)
Indeed - I totally agree. Perhaps, since you know Bob, that could be arranged? I'd be WELL up for that! :exactly:
However, I'd still love to find out what crystals both T/Ts use - for the simple satisfaction of knowing if the one in the Monarch is technically superior (even if not in practice). If it isn't any better, we can discount that as being the reason why the Monarch might sound better than a Techy.
Marco.
sq225917
23-01-2012, 18:19
If it sounds better it will be down to removing the electronics, and the integrity of the platter and plinth, certainly not 10ppm better xo accuracy. ;-)
Indeed! However, it would still be nice to know the crystal compliment used in both :)
Marco.
WOStantonCS100
23-01-2012, 20:28
Indeed! However, it would still be nice to know the crystal compliment used in both :)
Marco.
Agreed.
WOW!!!!!!!!! Lots of good questions, and thoughts for discussion. I will try to answer them all, in order. If I miss yours, bang on my ear. It is only a senior citizen moment.
If what you say about sourcing crystals is true, then I have a big question for Inspire about their Monarch turntables. They say, "...such as a new
quartz chip of greater spec..." So, either someone has already done what you say only has a slim chance of being possible or the Inspire folks aren't being honest. I would love to know which one it is.
I would never say they are dishonest. The guys in marketing tend to get all excited about little things. It is outside of their purview, and things that are insignificant, to the technical guys, seem like a big deal to the non-technical guys. And they tend to blow them out of proportion.
Besides, it makes for good copy.
Thank you Patrick, that's very useful information. The crystal type as far as I can see is a HC49 low profile can.
So, if we assume for the moment that the crystal cannot be improved upon, we are left with two scenarios:
1) Lift the crystal from the PCB and make a temperature controlled environment for it, say between 40-60C.
2) Lift the crystal from the PCB and put it into a better/more stable oscillator circuit.
The question is, will either of these give us lower jitter than the crystal in the AN6680 circuit fed with a very clean power rail?
Temperature control will do nothing for jitter.
Stability has nothing to do with jitter.
Jitter is, for the most part, a function of the parameter we call "Q". There are 2 values: the unloaded, which is the Q of the crystal, and the one that really counts. Which is the loaded Q.
Loaded Q is the Q of the crystal, when it is actually in the circuit. All oscillator circuits will lower the Q. Laws of physics at work. You can take a high Q crystal, and load it the wrong way, and it will perform poorly.
However...............
There are lots of other things that enter into it. I have lots of high Q crystals that do not perform very well. Lots of things enter in, most involve the presence contaminants, inside the crystal can.
As I said "If it was that easy................"
That's an obvious and demonstrable claim, most simple Xo come in one of two specs, 30ppm or 20ppm, other than that you really would be specifying an uber part in a oven and a decent tcxo is going to cost a lot more than Bob could afford to put in that deck. The simple way to find out is to look at the part currently in the 1210, if it's the 30ppm piece then It can be improved, if it's a 20ppm then it really can't.
I view all such 'marketing' claims with healthy skepticism. I'm with ART on this one.
Ah, the old "Ours is better, because it is x ppm, and yours is y ppm" argument.
OK............it is useful spec, in terms of absolute accuracy. But, in this case............
Let's look at this. A crystal is designed to operate into a specified load, and we will say it is 18 pF, for discussion. What this means if you stick it into a circuit, that presents the crystal with a 18 pF load, then it will oscillate at the right frequency.
Sort of. Within reason.
20 ppm. 30 ppm.
What this means "If you stick in a 18 pF circuit, it will oscillate at the specified frequency, within +/- 20 ppm.
Translated: 4 MHz clock.............20 ppm..........will be off no more than +80 Hz, or - 80Hz.
When it comes to your TT (and you have absolute pitch), that note that is supposed to be 440 Hz will be off as much as 0.0088 Hz. I am not a musician, so I will leave it to someone else to tell us how many cents it is off.
There, ppm demystified.
Has no bearing on jitter, contrary to what many of our Asian buddies will tell us. Their schtick is "Good quality!" Ok, but, being polite, their measure of quality is much different from ours. When it comes to crystals/oscillators, this is their sole measure of quality.
Other than...............yeah, price. Which is price, not quality. Try telling those guys!
BTW..............those fancy ovenized clocks, kinda sorta like what someone will stick in your DAC (for an extra $10,000!) start at around $500. Give or take a few bucks. Yes, they have good phase noise. And those guys will make pretty much any frequency, and one, if you only need one. All it takes is cash. And lots of it.
Pat,
Your comments regarding sourcing crystals, and their use, is helpful. Industry is slowly taking us all down to the lowest common denominator. Fortunately there are still those who are dedicated to making things better.
Perhaps you would care it illuminate us as to why you think there are no regulators capable or regulation up to 100 MHz.
Regards
Paul
AH! Good question.
OK, let's take something most DIYers have run into: LM317. Your basic regulator, that operates on feedback. Let's look at the data sheet.......
Output z, at 1 kHz, is 3 milliohms. Yep, pretty good. But, the feedback is already starting to fall off, which means it will rise on a decade per decade rate. At 10 kHz.........yep, up to 30 milliohms. 200 milliohms, at 100 kHz.
Hmmm...........is that right? Yes, because............that cap you need to make it stable starts to enter in. So, the rate will slow down. At least until the cap hits its self-resonant frequency. (Which is something that also deserves discussion, but not today.) When we get to 1 Mhz, it is now 1 ohm. Doesn't seem like much of a regulator, to me.
If we extrapolate, using the 1 MHz value, and discounting the effect of the cap (which in this case will probably be past its self-resonant frequency), we get 10 ohms, and 100 ohms, at 10 & 100 MHz, respectively.
Let's look at something that does not use feedback, so there will not be falling loop gain, vs frequency: the simple emitter follower.
Some nerd will probably point out that an emitter follower does have internal feedback, and blah, blah, and more blah. (If you want to argue that, I bet some guys at DIY Audio want to argue with you. I don't!)
Ignoring all of that............does its impedance stay constant?
No...........
Some of you may have noticed the output will "go inductive". Which means it will rise, just like an inductor does. So, we chose to say "it has gone inductive."
Where does it start to become inductive?
100 kHz.............maybe 200 kHz.............
Google "alpha transition frequency". That is the point where a follower becomes inductive.
Thanks, Simon :)
So if that's the case, and as you say likely what Inspire have 'improved' in the new crystal that they're using, it's not going to account for any huge improvement in sound.... Is it? Therefore, whatever is making the Monarch sound so good (as per the reviews), if you are right, obviously isn't the new crystal.
The only way to achieve a genuine upgrade in that area, it would seem, is to have a top-notch bespoke crystal designed, as Partick has outlined. And based on what he's said, that ain't going to happen anytime soon!
What needs to be done, so that we're dealing in facts, not fiction, is for the crystals used in both the Monarch and the Techy to be identified, and that information reported here. Who's up for that job, then?
Marco.
Hey, it may very well sound better. They probably tweaked something else. Saying it has better stability, crystal, etc., sounds more high-tech than.........well, something simpler, like buying a cheap, industrial-grade cap, that improved performance. We all know that only audiophile grade caps can make it sound better!
I think they call that "artistic license".
Dingdong
24-01-2012, 04:36
Has anybody looked up 4.194304 Mhz crystals as an alternative to 4.19328MHz?
That would represent a 0.024% speed error, so it would be possible. However, according to Patrick it's unlikely that a crystal swap will be an improvement.
Excellent replies, Patrick. I'll leave the technical stuff to the techy bods on here, as unfortunately most of that stuff goes way over my head. However:
Hey, it may very well sound better. They probably tweaked something else. Saying it has better stability, crystal, etc., sounds more high-tech than.........well, something simpler, like buying a cheap, industrial-grade cap, that improved performance. We all know that only audiophile grade caps can make it sound better!
I think they call that "artistic license".
Indeed, and that could well be the case... What needs to be done is for someone who knows what they're looking for to take a wee peek-a-boo inside the Monarch and see what lives in there, and then report back with the info ;)
Btw, I love this bit on your website:
Don't ask when.......when it happens, it happens. We are working on it. We can either work on it, or answer all of your questions. Only one is going to happen, ok?
--------------------------------------------------------------------------------
OK, the DAC is close to being ready. USB and SPDIF inputs. And they sound pretty darn close to each other. So, there!
Awesome!! :D
Marco.
Paul Hynes
24-01-2012, 13:21
Pat,
It was a good question but it only raised industry standard answers from you. In fact you have not really answered the question at all. You and I have been here before.
The LM317 characteristics are well known, as it is an industry standard three terminal regulator that has been around for decades, and the data sheets show this information. I stopped using this type of regulator in the 1980’s because the performance just was not good enough for high performance power supplies, even for analogue use.
The reason you have given why the LM317 has poor regulation is one of the reasons I design for much wider operating bandwidth in my regulator designs and have been doing so since the 1980’s progressively moving the boundaries further. I documented this exact reason for rejecting this type of regulator for high performance power supplies in a series of articles in the UK underground magazine "Common Ground" during the late 1990's. The performance of the LM317 in audio power supplies was being questioned much earlier than this by audio enthusiasts, Sultzer, Jung, Marsh, Didden etc through the 1980’s.
Things have moved on a lot since then.
Regards
Paul
Sorry for the old thread resurrection!!!did this go anywhere???
Not sure what a better clock would achieve other than maybe more accurate rotation speed.
As already discovered there are no premium options for an oscillator unless purchased in quantity as a bespoke order. I may have an option on a discrete clock that will utilize the original xtal but should improve performance. Just thinking out load and wondering if its worth the effort!
Not currently, Ian. I am, however, very interested in a superclock implementation for the Technics. It has nothing to do with rotational accuracy - after all, the deck is pretty accurate as it comes. What I want to hear is the effect of reduced jitter in the phase drive to the motor coils.
If you have a discrete design for use with the original crystal in mind, count me in. Continue via PM if you prefer.
Wakefield Turntables
29-11-2012, 13:46
:popcorn:
sq225917
29-11-2012, 14:40
Martin, you seem to be throwing the 'jitter' term about willy nilly. What do you mean by "jitter in the phase drive to the motor coils" ? Is there a D/A process taking place?
There's a clock involved, Simon, and some digital logic. This clock is used to derive the motor coil drive phases. Therefore time domain jitter will exist, no matter how small. You could translate that as noise, but small amounts of it will be getting into the coils and causing some fuzziness to the drive signal.
Wakefield Turntables
29-11-2012, 15:59
So the idea is to steady these signals as much as possible with a more upto date clock to try and stop "noise" getting into the coils and ultimately into vinyl replay. Right or wrong :scratch:
I'm much more familiar with the effect of clocking digital circuits in CD players and I'm not sure if there would be any audible improvement adding better clocking to the techie.
No harm in trying.
I've been following progress on a discrete clock design that is based on a standard type xtal and runs 2 oscillators out of phase with each other which should give better PSU supply noise rejection (don't ask me how cos I really don't know!!!) . Its similar to the clocking that has evolved in the "EC Design TDA1541 NOS" thead on diy audio.
Hopefully I should be getting a couple of PCB's to try and I thought as the techie has an odd freq and there is only a std type xtal available it might be worth trying.
That's pretty much it, Andy. As you know, regulating the power supplies with Paul's on-board regs has gone some way to helping that along. I guess (and it's only a supposition until I can hear the results) a highly stable clock would help to get even cleaner drive current into the motor windings.
How does the drive current fuzzyness translate into sound?
Wouldn't their be a fair old smoothing of speed due to the innertia of the deck compared to fast adjustments of drive current?
Must also depend on how the servo type thing works - are different currents used to vary the turning force or is it down to timing of the currents to the coils?
If the servo opperates via changing the amount of current to each coil (i.e. turning force at each point) then the timing of that delivery would stay constant and only determine absolute speed accuracy and the speed slider circuit quality might have a much much higher order of magnitude of effect (or removing it might be better). It might not to be to do with anything in the servo loop.
That 4MHz seems familiar as if it is the same value used in the Pink Triangle Too PSU. The Too PSU uses logic to recreate an AC drive to the same Premotec motor as used in the Linn.
Reid Malenfant
30-11-2012, 22:40
1. How does the drive current fuzzyness translate into sound?
2. Wouldn't their be a fair old smoothing of speed due to the innertia of the deck compared to fast adjustments of drive current?
3. Must also depend on how the servo type thing works - are different currents used to vary the turning force or is it down to timing of the currents to the coils?
4. If the servo opperates via changing the amount of current to each coil (i.e. turning force at each point) then the timing of that delivery would stay constant and only determine absolute speed accuracy and the speed slider circuit quality might have a much much higher order of magnitude of effect (or removing it might be better). It might not to be to do with anything in the servo loop.
That 4MHz seems familiar as if it is the same value used in the Pink Triangle Too PSU. The Too PSU uses logic to recreate an AC drive to the same Premotec motor as used in the Linn.
Apologies for being lazy, adding numbers makes things a tad easier.
1. We don't know, but it'll be fun finding out.
2. Once the platter is spinning there shouldn't be much of any difference in the current fed to the stator coils.
3. The Technics has a PWM feed to the coils (Pulse Width Modulation) at a fixed frequency by the crystal. The time that the coils are powered is varied & thus the current is varied. Most current will be used at startup as this is when the most torque is needed. The PWM circuit simply turns each coil on for longer & as a consequence more current is drawn & more torque is generated. As it gets up to speed the pulse width fed to each coil will reduce until some kind of near equilibrium will be reached.
4. You are assuming the timing stays constant, but I'm assuming that it may not well be so, this is why a more accurate clock & better timing might improve things on a fully fettled deck :)
But what do I know :cool:
Jitter in the motor drive could translate as rotational jitter in the platter spin. I'm not saying it will be audible, but it could be. After all, no-one thought that jitter in the clocking circuit of a CD player would be audible - how wrong they were.
sq225917
01-12-2012, 00:36
I'm surprised that they use a XO to create three lagged motor drive phases, that's a very odd way of doing things when two capacitors would give exactly the same effect. Are we sure it's implemented that way?
Time would likely be far better spent on a better compensation mechanism to remove their tendency to hunt and overshoot.
Jitter in the motor drive could translate as rotational jitter in the platter spin. I'm not saying it will be audible, but it could be. After all, no-one thought that jitter in the clocking circuit of a CD player would be audible - how wrong they were.
There's jitter and jitter and jitter.. The same term gets used to relate to very different things.
I'm not entirely convinced that jitter in the clock crystal per se is a cause of "jitter" in a CDP although the whole clock circuit and how it interacts with the chip (Dac or whatever) may have an effect. There are many accomplished digital designers out there who do make final judgement of their work on sound who would dispute the effect of a superclock being to improve the sound of a player with an already well designed clock (not just a white paper circuit copy). It may subtly change the sound but not necessarily improve it.
With a turntable, the sound is coming from the cartridge and the arm is probably the strongest influence on that cart. The TT itself is a combo of drive, plinth resonances, bearing quality and platter interaction with the vinyl with perhaps the drive being the lesser of those. Then on a well designed drive system is the eccentricity of a record causing more pitch instability than the drive system? The 1210 does have a well designed drive system even if there are still faults and compromises that can be sorted out with upgrades. Probably a drive system has more of an effect on a belt driven tt.
Then there's the amount of smoothing of servo mechanism effects by simple physics . Many bad servos out there are quite crude yet, whilst they might lack drive and pace in the sound on a cheap deck, we don't hear the much finer detail of the fast working adjustments that the servo is making - it's masked by the momentum of the platter.
So you cannot compare the two (CDP players and turntables), even if the same word "jitter" is used.
IMO changing one component on the drive circuit without changing the whole design for an even better one might just be a too miniscule a change to warrent both the cost and effort..
Still, I would never tell someone not to give it a go. So give it a go and see what happens.
If you have a discrete design for use with the original crystal in mind, count me in.
With the crystal you have, the design won't matter. All will perform the same.
When you get one that costs $50-100, then you can get picky on the design.
Jitter in the motor drive could translate as rotational jitter in the platter spin. I'm not saying it will be audible, but it could be. After all, no-one thought that jitter in the clocking circuit of a CD player would be audible - how wrong they were.
Don't know if any made it across the pond, but in the late 80s to early 90s, there was a product called the IsoDrive, that was a plastic doo-hickey that went on top of the CD, in Philips drives. It made a significant difference, and the difference was identical to the one lower clock jitter made. The guy who made it didn't know why it affected the sound the way it did, just that increasing rotational stability had to be good.
With the crystal you have, the design won't matter. All will perform the same.
When you get one that costs $50-100, then you can get picky on the design.
Are you saying that the limiting factor will be the xtal?
With the various clocks I've had and built for CDP's I've definitely found that the power supply makes a difference. I realise that better oscillators with real interesting parameters quoted like phase noise will ultimately out perform something like the eBay oscillators with nonsense performance figures quoted. I would say that the quality and suitability of the supply rail will allow an oscillator to perform optimally.
What I'm proposing here really is a suck it and see approach. The simple circuit would be very cheap to implement and if it doesn't work out to be any improvement, I'll use the PCB's in CD upgrades.....simples :D
I would agree it's worth a try - using a dedicated complete supply for a CDP clock makes a difference, with or without a better crystal (no noise in return path from other shared devices as stock), so it will improve quality of crystal reference. Points is whether that translates to an audible improvement in a DD turntable. Only one way to find out :)
Richard
Are you saying that the limiting factor will be the xtal?
The crystal will always be the limiting factor.
With the various clocks I've had and built for CDP's I've definitely found that the power supply makes a difference. I realise that better oscillators with real interesting parameters quoted like phase noise will ultimately out perform something like the eBay oscillators with nonsense performance figures quoted. I would say that the quality and suitability of the supply rail will allow an oscillator to perform optimally.
Any difference a supply would make would almost likely be in the noise floor. We have not found (with our uber-exotic test equipment) all that much difference in supplies. But, you must note that we do not measure anything above 1 kHz, when it comes to jitter frequency. Which is the area one would be looking, if they were interested in the noise floor.
Having said all of that..............
There are lots of folks claiming to hear differences in supplies, and I would not dismiss their claims. Only to point out the differences between a really good crystal, and the ones 99% of us have, is much more dramatic.
Now, as for the actual schematic...........
Yes, I contend it won't make much difference, unless you are really overdriving the crystal. With the common ones, the crystal will swamp any effects of the design. When it comes to really, really good ones, then everything matters, if you want it to perform at its best. In this case, what is perhaps the most important parameter is drive level. Too cold, and it will be on the noisy side. Too hot, and you run the risk of not only fracturing it (which I have never seen), but more importantly, it will have stability problems. So, there is a narrow range of drive levels, that will work. Unfortunately, it takes equipment most companies do not have. (Which is good, because we pad our income measuring stuff for other companies.)
One very peculiar effect we have noticed, and lots of our "clients" think we are nuts (we are, but for other reasons) is that if the drive level is not right (which usually means too low), you will see a lot of mains-related spurs, in phase noise plot. In all likelihood, they are not spurs, but mains noise that is picked up by the circuitry. So, if you see lots of 60 Hz (in our case), you know the drive level is not optimum. A slight tweak can reduce it by over 10 dB. In specific, it would mean changing the series R, in the typical IC Pierce circuit, by only a few ohms.
Which reminds me....................the one you see, in 99% of the publications.................
Wrong, in one way or another. You need to create a 90 degree phase shift, from the output of the gate, to the input of the crystal. The only way to do that is with a RC network. Yes, you could just use the R of the gate, but as low as it is, you are going to need a really big cap. And the gate won't like looking into that low of a Z. So, that circuit must use a series R. It also helps to keep drive level at a safe difference.
So..........as your homework......................stick 100R in series with the output, back to the crystal, and first shunt cap. Figure out how much phase shift there is, at the operating frequency, with only the usual 33 pF cap.
Then try it with something in the range of 1-10 nF. Tell me which one makes more sense.
Wakefield Turntables
07-11-2014, 18:36
Has anyone else considered this?
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