If it's possible, then why did you not do it?
Your HTS5.1 already failed in simulation, you have never proved the contrary
in more than 1 or 2 or more years. Negative real part of input impedance between
800 KHz and 80 MHz -> unstable with the right inductance on the input.
I have one that is both unconditionally stable, without feedback around some op amps
to the source and non-impressed by temperature; some people on diyaudio have it.
Obviously, I don't feel like proved wrong.
Gerhard
Your HTS5.1 already failed in simulation, you have never proved the contrary
in more than 1 or 2 or more years. Negative real part of input impedance between
800 KHz and 80 MHz -> unstable with the right inductance on the input.
I have one that is both unconditionally stable, without feedback around some op amps
to the source and non-impressed by temperature; some people on diyaudio have it.
Obviously, I don't feel like proved wrong.
Gerhard
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Tell this to the countless members that build it. Your simulation is obviously wrong, doesn't reflect the implemented final circuit (you missed even the servo circuit principle of pole-zero cancellation to avoid peaking), and you are looking in the wrong place, ever heard of "loop gain" and "compensation"? But I am willing to debug it for you, if you can afford my hourly rate. As a free benefit, you could then stop sleeping with this wrong simulation under your pillow, ready to pull it anytime when you see my posts. This behavior is exclusively licensed to Andreas, with my PLL noise results.
BTW, a MC head amp is not a low noise measurement amplifier, but don't worry, be happy, and enjoy your grudge
!
BTW, a MC head amp is not a low noise measurement amplifier, but don't worry, be happy, and enjoy your grudge
!
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You guys want to help out andrea? Just present the proof that his oscillator made audible difference in objective listening comparison.
And so, what's your problem?
If you want I can subtract 30dB of phase noise to the plot of your PLL oscillator in the TimeLab software (the one wich implements the cross correlation, not the ADCs/FPGA) so it will become the best ever built.
For this job my hourly rate is for free.
It's a pity.
With the best oscillator ever built you could have supported the debate with Gerhard a little better.
I don't, I just want you and syn08 to stop reiterating the same message. Of course there is no hard evidence that Andrea's oscillators make an audible difference, but so what? There is no reason at all to believe that amplifiers with 1 ppm distortion sound any different from those with 1000 ppm distortion, but low distortion amplifier threads are usually not made unreadable by hundreds of posts from two people demanding controlled listening tests or measurements made by independent laboratories.
In fact, if I remember well, syn08 even admitted on this thread that he had designed a very low distortion amplifier. Shame on him! Following the logic of you two, he should first have conducted psychoacoustic research to find out what level of distortion is audible, then figured out how much distortion studio equipment and loudspeakers produce, take the worst of them all and then design his amplifier to only have marginally less distortion or be prepared to justify himself.
A reread of the forum rules is necessary (it helped me refrain from responding to some of this, perhaps it will help others also). The arguments are now laced with personal insults. Harassment and trolling are against the rules. If you can’t abide, just add people to your ignore list and urge other not to repeatedly respond or quote posts dosed up with jabs and venom.
@ even harmonics, I have no idea if it's audible, none at all. I suspect its beyond audibility compared to an already very good clock implementation. Nonetheless, I appreciate the quest for perfection.
I will dignify your comment with a response here, although it is off topic, I hope it will be tolerated.
There are a few fundamental differences:
a) the PGP amplifier (still available on my web site) was from the very beginning defined as a technical challenge of reaching 1ppm THD @20KHz. At no point it was claimed to provide any sonic improvement, in fact the scope of the project was a strict technical spec.
b) the project was made public to everybody and their dog, with schematics, Gerbers, wiring recommendations (to avoid magnetic effects, which was probably the biggest challenge), measurement techniques, adjusting procedures, etc... No group buy was initiated (although I was several times asked to do so).
c) the design was commented in audio all over the world (I've joined lots of audio forums at the time, to provide advice and respond questions, here's an example: ????? ??????? and many successful builds were reported, in India, Russia, Czech Republic, US, etc... I did my best to discourage any replication for commercial purposes (I refused to hand over the design files and the PCB layout database), not sure how successful.
Now please compare with the Andreas approach, that include among other, outlandish claims about the sound quality of the clock, group buys for profit (self admitted), no source code for the software, encrypted FPGA configurations, etc... and decide what is/was closer to the DIY spirit.
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I see Ian doing the same thing, certainly similar, but I don't see you continuing to argue and break the boxes. to not come back you have your forum where you are so noble ...
With due respect, you've been off topic for weeks here and in the FIFO threads. Why stop now when this could be a useful learning experience.
There are a few fundamental similarities:
You designed built and refined the PGP amplifier. It appears to be as you claim SOTA. I think it is a stunning achievement. I would love to hear it along this your vinyl source. I enjoy digital and tubes, but fully accept that what you have built could have properties that are wonderful.
Much like Andrea's clock and Ians FIFO.
Many were interested in following your journey and then sought to build one of your designs. Again, similar. I hope no group flamed the global followers and called them sheep, idiots, and chastised them for celebrating the designer.
When complete you listened to it. You commented in great detail about the SOUND QUALITY produced by the design. You invited a group of several people over for a structured listening session. You list the variety of top tier commercial audiophile amps your guest listeners have to give credibility to your claim of SOTA sound quality. You explained that your BOM cost $1000 but the commercial amps that it bests would be $30k.
Wow. The similarities are staggering. Every time we mention that we have listened to systems running Ian's FIFO and / or Andrea's clock and claim quality sound rivalling $30k components you flame us. If we celebrate the incredible price/performance of our creations you call us idiots.
A staggering double standard. Why can you not see this?
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Still no proof to speak of. I guess Andrea is totally out of luck in getting help from his followers.
Do you think that would've happened if you picked out true audible traits of Andrea's product and presented here?
There is a simple explanation: Ian makes very little unsubstantiated claims and his projects seem to be based on solid engineering. He implements and optimizes what is in general known to affect the SQ, by indeed occasionally over designing his projects, but seem to know, for example, that the sensitivity of hearing to jitter is in the 100's of ps at best. And when challenged (which I did myself several times) does not claim he was insulted and starts throwing **** in the fan. He responds calm and tries to support his findings. Which may or may not be correct, that's besides the point. If the points are still under contention, he agrees to disagree, and that's it. Ian makes mistakes (like the one with the phase noise measurements using a scope) and I myself did not defend them.
Long story short, Ian doesn't peg the BS meter off scale,
You skipped all the differences and brought up a few irrelevant points.
But nevertheless, there is yet another fundamental difference that I missed; in the last ten years or so, the definition of DIY Audio has changed significantly; then, DIY Audio was about designing circuit topologies, boards, soldering parts, measuring the results, optimizing the results, evaluating the sound. Today, it looks like DIY is about purchasing prebuild assemblies and kits, putting them together on a wood board, tweaking by filling boxes with sand, and sharing anectodic sound quality reports. Funny enough, the tubes guys remained the crowd closest to the original spirit, while the emerging digital audio the farthest.
From this perspective, your view of DIY Audio is fully understandable.
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For completeness, Joseph informed me that there was indeed a large difference in the way the reference voltages were generated between the two DACs of which he measured the output signal spectrum. The D90, which had the worst sidebands around the signal, uses ADP7112 references which have lots of subsonic noise that rolls off at roughly 9 dB/octave. It's only 600 nV/sqrt(Hz) at 10 Hz, though, instead of the 6 uV/sqrt(Hz) that I calculated. See the 5 V trace of figure 33 of https://www.analog.com/media/en/technical-documentation/data-sheets/ADP7112.pdf The other DAC used an LT3045.
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