Prima Lunacy? (SuperTubeClock)


I am planning on upgrading my tube amp when its current set of tubes start to go.  So I've been doing a bit of perusing online, and was really considering the Prima Luna integrated amps until I read about "the world's first tube-based data clocking device: the SuperTubeClock™"

Did I missing something or is this just about the most obvious snake oil sales job?  For what I am understand the Prima Luna Engineers are using a tube-based oscillator in lieu of a quartz crystal to generate the DAC chip clock signal.  Their blurb lists reduced jitter and noise as the advantages.  AFAIK the noise in a timing signal should be superfluous since it has two values 1 and 0, and anything in between (noise) is ignored.  If the clock signal "noise" is leaking into the final analog output, then there are big problems with the DAC chip.  With respect to jitter, I would expect the inaccuracies of a high-quality crystal oscillator to be measurable only in the nanosecond or picosecond range.  Can an analog-style oscillator really do better (and does it really matter)?

Another thing that stuck me is that the clock triode is soldered in, and there is mention of it lasting 5 - 10 years.  When it goes bad, do owners have to send their DACs to Prima Luna to be refitted with new - and possibly rare and otherwise unavailable - clock tubes?

Thoughts, anyone?
tinskip
Prima Luna are made in China. That alone is reason enough to knock them out of contention. Your question about customer service might be about this tube but winds up drawing attention to the general problem of having something made in China. Never a good idea, and one that is only getting worse and worse as time goes by. 

Have you looked at Raven? https://www.youtube.com/watch?v=Gcd76DZmbdY Much better quality and made right here in the USA.
I owned a Primaluna PL2 for several years.  Designed in the Netherlands, built in China and distributed and supported by Kevin Deal at Upscale Audio.   Solid build, great sound and great customer support.  Even though i bought mine used Kevin helped me out with a small problem-bad tube i was new at this.
Isn't Line Magnetic made in China? Would not turn down those amps.
I have a Melody integrated, same thing. Designed in Australia, made in China. When I bought it, dozen or more years ago, thought oh how great providing some good jobs in China. 

Right after I get the amp find another story put out by some reviewer who actually went to China to see how they are made. All the people live and work in the same building. Because when you work 20 hour days for a dollar there's no time to be commuting back and forth and no money even for a bicycle anyway. Just wonderful.

But hey I'm sure Line Magnetic and Prima Luna would never do anything like that. They probably have some magic fairy dust or something to keep the price down.
MC is showing his ignorance regarding Prima Luna. The company has been in business for over 20 years, is designed in the Netherlands and they have been built in the same Chinese factory since day One. Of course, nothing is better than What MC suggests. If he says it is good, then it must be the best. I am surprised MC didn’t call it the “Kung Foo” DAC. On a lighter note, Washington State is having a resurgence of Covid 19 in the more rural areas. How can that be, it’s a big hoax😂😂😂?  It is also so nice that MC is very concerned for the Chinese workers. 
That's an insult not an argument. 

I said Prima Luna are made in China. You agree Prima Luna are made in China. Where is the ignorance? I mean, aside from you being ignorant of the meaning of words, and showing a lack of reading comprehension.
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My last Post was deleted:
MC you diss everything that is made in China. That WAS my point. .  You mention reading comprehension.  I suggest you try it sometime. 
Oddly, as recently as 7 months ago @millercarbon had been recommending Prima Luna integrateds.

https://forum.audiogon.com/discussions/seeking-advice-upgrading-decades-old-audio-system/post?highli...

Apparently the conditions for the Chinese workers and the structure of the government has really deteriorated since then.  lol
After reading the writeup on the "SuperTubeClock," and examining the waveform photos it provides after going to the URLs of the photos themselves (where they are presented in an easier to see form), I don’t consider this writeup to be BS or the SuperTubeClock to be snake oil. While the writeup raises some questions in my mind which are left unanswered/unexplained (see below), and although I certainly find a lot of other audio marketing literature to be BS from a technical standpoint and a turnoff when it comes to considering the product for purchase, I don’t in this case.

AFAIK the noise in a timing signal should be superfluous since it has two values 1 and 0, and anything in between (noise) is ignored. If the clock signal "noise" is leaking into the final analog output, then there are big problems with the DAC chip.

That is not correct. Noise on the clock signal applied to a DAC chip will result in short-term random or pseudo-random fluctuations in **when** transitions between 1 and 0 and/or 0 and 1 are sensed by the chip, causing the timing fluctuations that are referred to as jitter. (Generally speaking those transitions are sensed in the vicinity of their mid-point, i.e., roughly half-way between the two voltage states of the clock signal). And generally speaking that is widely recognized as being a significant issue in digital audio, to a greater or lesser extent depending on the particular design of course. It is not a matter of the noise "leaking through," it is a matter of the effects of the noise on timing.

In a thread a few months ago one of our technically astute members, @Kijanki, explained it this way:

Let me try to explain jitter. Imagine you play 1kHz sinewave recorded on your CD. Digital words of changing amplitude, representing sinewave, are converted in even intervals into analog values by D/A converter. You get analog 1kHz sinewave.

Now imagine that these time intervals are not exactly even, but are getting shorter and longer 50 times a second. Now you won’t get only 1kHz sinewave but also other frequencies, mainly 950Hz and 1050Hz called "sidebands". Distance from the main (root) frequency depends on the frequency of the interval change (jitter), while their amplitude is proportional to amount of interval change. These new sidebands have very small amplitude, but are not harmonically related to root frequency (1kHz) and that makes them still audible.

With many frequencies (music) there will be many sidebands - practically a noise added to music. Sidebands have small amplitude that is proportional to amplitude of the signal. This noise stops (is not detectable) when music stops playing. You can only hear it as lack of clarity in the music (since something was added).

Things the writeup leaves unexplained include the following:

1) **How** is the sine wave produced by the tube converted to a square wave? Presumably that is done by solid state devices, which may or may not introduce significant amounts of noise themselves and cause some amount of jitter regardless of how clean the signal provided by the tube may be. It would be nice if some indication of **overall** jitter performance were indicated.

2) Waveforms are shown for 8.4672 MHz and 42.2 MHz. What rate is actually being used in the D/A conversion? While the writeup and the photo for 42.2 MHz indicate that risetimes and falltimes of the square wave are about 1.67 ns, a corresponding figure is not presented for the 8.4672 MHz case. And it appears based on the waveform photo that those times are about 4 or 5 ns, considerably slower than at the higher speed.

In any event, I wouldn’t consider this writeup to be something that would dissuade me from considering this DAC, if I had a need for a new one. I certainly can’t say as much about a lot of other marketing literature I have seen from other manufacturers.

Regards,
-- Al


Here’s two DACs similar in price. 
 the Mytek Brooklyn Bridge

Maximum output level / Impedance. 9.6Vrms / 73ohm
A-wtd S/N ratio (S/PDIF / USB) 112.9dB / 112.8dB
Distortion (1kHz, 0dBFs/–30dBFs) 0.0003% / 0.00017%
Distortion & Noise (20kHz, 0dBFs/–30dBFs) .0005% / 0.00035%
Freq. resp. (20Hz-20kHz/45kHz/90kHz) +0.0 to –0.0dB/–0.4dB/–1.9dB
Digital jitter (48kHz / 96kHz) <5psec / <10psec
Resolution (re. –100dBFs / –110dBFs) ±0.1dB / ±0.5dB
Power consumption15W (1W standby)

The Prima Luna EVO 100

Maximum output level / Impedance. 2.15Vrms / 2.35-12.2kohm
A-wtd S/N ratio (S/PDIF / USB) 104.9dB / 105.0dB
Distortion (1kHz, 0dBFs/–30dBFs) 1.07% / 0.025%
Distortion & Noise (20kHz, 0dBFs/–30dBFs) 1.03% / 0.026%
Freq. resp. (20Hz-20kHz/45kHz/90kHz) –1.6 to +0.1dB/–0.5dB/–7.4dB
Digital jitter (48kHz / 96kHz) 160psec / 80psec
Resolution (re. –100dBFs / –110dBFs) ±0.6dB / ±3.5dB
Power consumption 53W

Specs from Hi Fi News

It mentions in the review the Prima Luna uses a crystal as the Master clock the tube is used in he side bandwidth oscillator.
Impedance ... 2.35-12.2kohm

Ouch! That would certainly make it a poor match for the input impedances of a lot of solid state components, especially considering the wide variation of impedance as a function of frequency. Additional detail from the review:

Output impedance is excessively high at 2.38kohm through mid and treble, increasing further to 3.5kohm/100Hz and 12.1kohm/20Hz

A lot of the other differences seem expectable given that one DAC is tube-based and the other is solid state. Although the EVO’s jitter numbers don’t appear to be anything to write home about. Again from the review:

Jitter, in practice, is influenced by noise and other interference emanating from every corner of the digital circuit and is reduced from the 330psec measured with the ProLogue Eight to 160psec (48kHz) and 60psec (96kHz) in the EVO 100, with ±100Hz and ±200Hz PSU modulations the key components.

(The references to 100 Hz and 200 Hz would be 120 Hz and 240 Hz in the USA).

Thanks, @djones51. Regards,

-- Al



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Wow, there are some seriously misguided views on some Chinese audio manufacturers. Very sad. If you did any research, you would find that the two brothers who started Line Magnetic have a great track record and that the LM facilities are far from your simplistic notion of asian sweatshops . Why are you so quick to judge people and their products, particularly in the hobby you partake, because of the country/politics they happen to be born into?

My last Post was deleted:
MC you diss everything that is made in China. That WAS my point. . You mention reading comprehension. I suggest you try it sometime.

If it was deleted, it wasn’t by me, nor was it at my request. That would make no sense. For as long as it was there anyone could look and see that was NOT your point. All you did was call me ignorant. Which is in fact an insult. "That’s an insult not an argument" is practically my calling card at this point, what with how often people incapable of reasoning fall back on insults.

Like right now, you’re insulting me again with the reading comprehension remark. Which if you had anything to back it up (ie, an argument) that would be fine. I would simply refer back to your original post, cut and paste, prove you wrong. Now sadly something neither of us can do. All because someone got upset and thought their feelings are more important than our ability to think and share ideas. However much others may disagree they are still only words and ideas. To try and force everyone to agree at the risk of harming someone’s feelings is tyranny of the worst sort as it is tantamount to mind control. I will have none of that.

I will ask however that if you are going to insult me at least have some ground or justification. Besides feelings, I mean. Otherwise when you get right down to it, what’s the difference between two kids on a playground going "No YOU ARE!" Or "I’m rubber and you’re glue words bounce off me and stick to you" if you’re not into the whole brevity thing.

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Own a Line Magnetic 518 integrated amp , very well built and very nice sounding.

https://www.monoandstereo.com/2017/08/line-magnetic-factory-tour.html
Doesn't look like a sweat shop factory but if you have some other definitive evidence of such please post it
MC, again, it’s because you diss everything Chinese made when your beloved Melody amp is made there.  You must be the exception to the rule?  I am tired of you MAGA people blaming everything on China. China makes many excellent products, get over it.  
Isn’t it convenient to be able to make claims and assertions freely with no facts or evidence to back it up? Also call those who keep tabs on such fake  things fake? It’s a very popular pastime these days.
"All the people live and work in the same building."
How is that different from many people all around the world over the last few months?
Almarg, thank you for your response, but I still remain completely unconvinced about the value of the SuperTubeClock for the following reasons:

(1) I have never heard of another case where an analogue-type oscillator was deemed more precise than a quartz crystal oscillator. Analog oscillators are subject to some degree of thermal drift.

(2) In the PrimaLuna page there are nice scope images for the output of the SuperTubeClock at two frequencies, but they are not being compared to anything. Why do they not show the output of a high-quality crystal clock?

(3) Even if the SuperTubeClock were indeed more precise / less noisy than a crystal oscillator, then the clock of the ADC which captured source audio signal would have to use one as well for the SuperClock-timed DAC to have much value. If both the ADC and DAC clocks have jitter in some situations the "jitters" may cancel each other out!  But then they could add up as well, I guess.

It would be nice to hear from people who have actually heard this DAC!

"I am planning on upgrading my tube amp when its current set of tubes start to go."

Don’t hold your breath, they will last a long time. I’m not a digital gear nitpicker, but have demoed one in my system for the CD deck. It did what it’s designed to do, and that is make the CD player a little less "CD sounding" I looked nice too, complimenting my PL HP.

The distributor is the one to address your long term concerns, not anyone here.

I went Denafrips Ares-R2R design. Le$$ and equally satisfying. My subjective opinion, of course.


Edit:

I misread your comments. I understood it as you already have a PL. Nevermind.



Apologies to the OP for digressing from the main topic but I want to share my opinion on the issue raised by @millercarbon. I also used to be of the opinion that we should buy a product that offers the best value regardless of the country of origin. But in the last 2-3 years, due to the nature of my work working with several clients, I have come to witness the shady nature of the Chinese government. Unlike @millercarbon, my beef is not due to the nature of labor laws and conditions in China, as frankly that is mostly based on rhetoric that might have had some truth to it a decade ago.

The Chinese government brazenly enters the markets in many countries, but goes out of its way to block access to the local Chinese market. It encourages dumping, IP violations, and unethical manipulation that makes it almost impossible for foreign companies to operate in a level playing field. It will be hypocritical of me to say that I will never buy chinese products, because in most cases I don't really have a choice. But I do look for alternatives whenever I can.
I just read PrimaLuna's page for their EVO 400 amp, and according to it, at the very bottom "OUR AMPS ARE PERFECT. BUT YOUR SYSTEM MAY NOT BE", they are the only ones who know how to make use of EL34's, and their amps are so awesome they can make up for crappy speakers.  Wow!  These guys really are full of it!

I guess I'll be looking elsewhere.  I have time.