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56 minutes ago, gmgraves said:

Where did you get the notion that Pass designs his equipment to “enable decent amounts of harmonic distortion”? I know one of his designers quite well, and he says that’s patent nonsense. One reason Pass uses class A in his amps is to reduce the distortions inherent in class A-B amps.

 

I could be wrong but he may be confusing "decent amount of harmonic distortion" with the use of negative feedback, a technique commonly employed in amplifier design to improve performance when properly implemented..

"Relax, it's only hi-fi. There's never been a hi-fi emergency." - Roy Hall

"Not everything that can be counted counts, and not everything that counts can be counted." - William Bruce Cameron

 

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3 hours ago, gmgraves said:

 

Where did you get the notion that Pass designs his equipment to “enable decent amounts of harmonic distortion”? I know one of his designers quite well, and he says that’s patent nonsense. One reason Pass uses class A in his amps is to reduce the distortions inherent in class A-B amps. 

 

 

Depends on who he is designing for. His DIY stuff is known for it, and this thread, as an example,  https://www.audiosciencereview.com/forum/index.php?threads/nelson-pass-amps.8034/, describes his tilt on the game, from the POV of various observers - his aim is to "make it sound good", above all else.

 

Yes, class AB has a major weakness in its concept - it is relatively difficult to completely negate the impact of crossover distortion; I have played with Spice simulations which show that even in ideal circuit setups that the glitch in the waveform is very hard to make completely vanish. Some very sophisticated designs can make it happen, but you then pay for that in that the circuit has a very high parts payload.

 

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Tell me, Frank, where did you obtain your knowledge that allows you to second-guess a piece of equipment’s power supply designs? How do you know, for instance, that (A) the capacitors you replace willy-nilly are an improvement over the original design? Do you do the maths? (B) when your PS mods are finished, what improves? Voltage regulation? Current sourcing? Lower ripple? (C) How do you measure these improvements to the power supply; or do you just “guess” that the equipment sounds better?

 

Explored this area over many years - it started because the original Perreaux had duff smoothing caps for the job, even though they looked like they could jump start a vehicle, 😉. Symptoms were loss of high treble quality when the PS was working hard; quite easy to hear - improved this area over several iterations, by throwing away those caps and introducing a design which had extremely low ESR - treble problem disappeared.

 

Spice does the maths for me, there's a thread over on diyAudio, that ran years ago where I was very active, that I've pointed to a couple of times - it's quite easy to show that real world supply circuits have trouble with voltage sag, because the parts are not capable of delivering the energy needed when the speakers are being driven hard.

 

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Frank, I have “read what you have done” for several years now. And just judging from what you have posted here, it doesn’t amount to a hill of beans. If you have, at one point or another, posted everything that you have done, then, that’s from  where I have formed the opinion that your “method” cannot possibly enable the improvements in SQ that you have bragged about.

 

I do what's necessary to get a particular setup to reach an acceptable standard - the original Yamaha, Perreaux, etc setup had sufficient raw quality, and was exceedingly simple; enough was in place so that it reached the convincing SQ level without that much needing to be done. Lower cost, and quality items have more shortcomings; it was a challenge to see if I could also push them to that point as well - and good learning. Key is ability to be able to hear what a system is getting wrong, and make good judgement calls of what should be worked on - every setup is going to have a unique set of weaknesses; no point in wasting time 'fixing' stuff that doesn't need fixin'.

 

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Those speakers are never going to disappear, and that’s my point.

 

They have got close - but no cigar. Problem is in the electronics; still too much low level distortion for my mind to be able to ignore.

 

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I have no idea. I have never seen that movie. At first, I mixed it up with “Where Eagles Dare”, which I did see when it was in the theaters first run in ‘67 or’68. But I don’t remember much about it or its characters either, so, either way, your analogy is therefore lost on me, Frank.

 

??????????!!!!!!

 

Don't worry 'bout it then ... 😉.

 

And, some news!! A new toy is on its way ... the Behringer active monitors I got some years ago turned out to need too much fiddling, tweaking to be a good candidate for a value for money, tarting up exercise - and, just came across something, literally today, that is a more visually acceptable, and capable active speaker, meaning digital in, 🙂 ... cross my fingers that this can deliver the goods, at a low effort cost.

 

Also, starting to play with some circuit simulation of Putzeys's recent class D amp modules - will be interesting to get a handle on what makes them tick ...

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7 hours ago, gmgraves said:

That’s why some of the best sounding amps, often don’t measure that way. For instance, the French Jadis tube amps have more than 2% THD (Total Harmonic Distortion) at rated power, yet the amps sound marvelous. Perhaps, this IS what Frank was talking about. Thanks for bringing that possibility to my attention. 

 

In part. Pass is correct in saying that FB won't automatically solve all the problems, and the classic output stage operating in class AB is a perfect example of this. The theory of feedback says that the circuit will be able to compensate for any discrepancies in the perfect behaviour of the signal through its path, by "counter-distorting" at the input of the circuit - an error signal is added to the true input; the amplifier is in effect always amplifying a distorted version of the waveform, which is neatly reversed as it passes through the signal path - a 'pure' version of what you want is then what the speaker sees.

 

The fly in the ointment, in most implementations, is that the signal drive to the output stage, that which is pre-distorted, remember, now has very fast slew rate parts at the crossover region, intended to "undo" the crossover artifact - but anyone who has tried to get a power output stage to have a very high effective bandwidth knows that this is far from easy, the characteristics of high power transistors in every way conspires against being "fast"- it can be a losing battle. Very clever, and very fast designs can get around this - think the Spectral brand here.

 

Higher level, but pleasant distortion can easily be superior to listen to, than quite low level, but irritating, and disturbing artifacts - this is why, say, class D can easily do a better job of getting the subjective SQ right, if the implementation is good enough - no crossover headaches.

 

Well done class A, extremely fast class AB, and good quality class D are all fine solutions - the last is where the future is, for obvious reasons.

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13 minutes ago, fas42 said:

Well done class A, extremely fast class AB

It should be : Well done Class,  extremely fast Class B.……….

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Class-AB is less linear than either A or B, and in my view its only legitimate use is as a fallback
mode to allow Class-A amplifiers to continue working reasonably when faced with a low-load
impedance.
Class-B
Class-B is by far the most popular mode of operation, and probably more than 99% of the amplifiers
currently made are of this type. Most of this book is devoted to it. My definition of Class-B is that
unique amount of bias voltage which causes the conduction of the two output devices to overlap
with the greatest smoothness and so generate the minimum possible amount of crossover distortion.

 

Audio Power Amplifier Design Handbook 5th ed - D. Self (Focal, 2009) WW

 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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Note this post just made,

 

Turns out that systems at every cost level benefit, and, those at the bottom rungs get the most benefit! Why? Because those components usually have the lowest level of engineering applied internally to give good isolation, and are compromised badly by poor quality mains, etc. Which is why doing extensive tweaking externally to shield the gear from the environment can often have the greatest audible impact for low cost items - if the internal circuitry is "good enough", then they can shine in terms of getting the subjective qualities of the sound in good order.

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11 minutes ago, sandyk said:

It should be : Well done Class,  extremely fast Class B.……….

 

 

Well, that's the first time I've seen that Self calls it class B - the usual understanding, that most go by, is using AB to describe it ... it makes things messy, if even the experts can't agree on the 'right' term to use ... 😁.

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Since a post I made recently really belongs here, I'll repeat it,

 

For me, cables are a  pretty simple concept ... they are merely a circuit path external to the boxes which allow all the components to form the overall circuit of the playback system; they either do this job, which is no different from that done by a 1mm long trace on a circuit board in concept, correctly - or they don't. The latter is what we don't want - which is why I hardwire, or equivalent, my cables ... this is now much closer to a robust version of a circuit link.

 

IME, the construction of a cable, the materials used to make it, its ability to reject interference from any environmental electrical noise, etc, combined with the relatively poor electrical integrity of the typical plug in, or tighten down, connection all combine to give each external link a "sound". Which I don't want. The finished cable link should work identically, in every audio significant measurable way, over many years of never being touched, or disturbed, to an extremely short, soldered link - that should be the goal; anything else will always be a compromise.

 

N. down the road did a simple experiment which demonstrated what's going on: he had low cost, ordinary wire, and an expensive cable - which when used conventionally showed what audiophiles expect to find; the ambitious link "sounded better". Then he alternately soldered the link with the cheapy, and the pricey items ... well, well - all the differences evaporated; there was nothing gained by using the "better" one - it was the hardwiring eliminating the distortion anomalies that the expensive cable 'helped tame' - a lot cheaper, wouldn't you say, 😉.

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Interesting find just made ... the nCore amp modules, by Hypex, were purported to be the bees knees as regards getting "perfect sound" - that is, by all conventional measurements there is nothing that they do wrong; they should be "fully transparent". However, some weren't as impressed as they should have been ... and lo and behold, there is indeed a 'weakness' in their implementation, as accepted by the designer ... https://audioxpress.com/article/purifi-audio-a-straight-wire-to-the-soul-of-music.

 

So what ... ? Well, we keep being told, by the objectivists, don't worry your pretty little heads about anything that could possibly cause any audible issues; everything is under control, because we have the measurements "to prove it", 😉.

 

Many a slip twixt ...

 

 

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On 4/7/2020 at 3:25 PM, fas42 said:

And, some news!! A new toy is on its way ... the Behringer active monitors I got some years ago turned out to need too much fiddling, tweaking to be a good candidate for a value for money, tarting up exercise - and, just came across something, literally today, that is a more visually acceptable, and capable active speaker, meaning digital in, 🙂 ... cross my fingers that this can deliver the goods, at a low effort cost.

 

And, they've just arrived - first impressions, on unboxing, impressive - for the money, 😉! Very meaty, looks good ... now to see if it works, etc, 🙂. ... And they do ... again, impressive - from dead cold, first disk tried, they did a very nice job with Beethoven Violin Sonatas, with Perlman and Ashkenazy - the same one as on my YouTube channel ... good tonality, can't pick anything obviously wrong - a solid tick!

 

Can anyone guess the brand - and, price?

 

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Also, starting to play with some circuit simulation of Putzeys's recent class D amp modules - will be interesting to get a handle on what makes them tick ...

 

In progress ... working off what some other good people have already done; sort of functions but still plenty to do - 500 amp spikes in the output devices won't give it a good lifespan, 😁.

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5 hours ago, fas42 said:

Can anyone guess the brand - and, price?

 

OK - I'll bite.

 

JBL Active Monitors

 

$600

 

To be clear, this is just a guess!

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.

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Nice try, 😉 ... Edifier S2000 Pros; in US dollars, 260 ...,

 

Edifier S2000 Pro Active

 

Not the stands though, they're extra. Obviously a copy of the style of a well regarded brand; in the flesh, they look and feel as impressive as the photo implies, pass the rap test easily - way more weighty than my original B&Ws, not a single thing gives the impression that they're a cheapie.

 

Hooked up, they deliver. Absolutely nothing done to optimise, just plugged in to test if they work - fed via optical, which, fool me 😜, I have never used before,and didn't trigger on the plastic caps - from an Aldi Blu-ray player. Listened all the way through on the first 2 CDs, the second was https://www.allmusic.com/album/no-1-blues-album-mw0001037012. All the guts, drive and balls of the bass solid tracks on this came over beautifully - Big Sound, easy peasy.

 

Perfect? Of course not!! More refinement, better treble, greater clarity and soundstage - but a solid foundation; easily livable with, straight out of the delivery box.

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4 hours ago, fas42 said:

Nice try, 😉 ... Edifier S2000 Pros; in US dollars, 260 ...,

 

Edifier S2000 Pro Active

 

Not the stands though, they're extra. Obviously a copy of the style of a well regarded brand; in the flesh, they look and feel as impressive as the photo implies, pass the rap test easily - way more weighty than my original B&Ws, not a single thing gives the impression that they're a cheapie.

 

Hooked up, they deliver. Absolutely nothing done to optimise, just plugged in to test if they work - fed via optical, which, fool me 😜, I have never used before,and didn't trigger on the plastic caps - from an Aldi Blu-ray player. Listened all the way through on the first 2 CDs, the second was https://www.allmusic.com/album/no-1-blues-album-mw0001037012. All the guts, drive and balls of the bass solid tracks on this came over beautifully - Big Sound, easy peasy.

 

Perfect? Of course not!! More refinement, better treble, greater clarity and soundstage - but a solid foundation; easily livable with, straight out of the delivery box.

The best stand type speakers use air motion transformers as tweeters. They would likely give these speakers the top end that you say these speakers need.

George

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3 hours ago, gmgraves said:

The best stand type speakers use air motion transformers as tweeters. They would likely give these speakers the top end that you say these speakers need.

 

I agree that the better technologies will be able to do a finer job with the top end - however, this is not where these speakers are showing the issues to be; as usual, it's the electronics which dictate the SQ that counts - and this is trivially obvious by shutting down other devices on the same power circuit.

 

I need to get a good handle on what counts - last night, a Bartok piano CD was not up to snuff; today, after a solid run of conditioning I couldn't fault the tonality on this disc ... anyway, I'll use this other thread,

to keep notes of how things are going; what I discover on the way.

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Just to note that it's the parasitic behaviours of the materials used in the make up of cables, and the designs and precise methods of their construction that become crucial, when a certain standard of SQ is reached - easily measurable RLC numbers have close to zero meaning at this point.

 

Cables are a great source of interfering noise, either picked up from the environment, or internally generated. Solutions are to eliminate cables entirely from the setup - the active speaker concept, which I'm playing with right now - or be paranoid with every aspect of how the connections between components are organised - what I have spent a lot of time investigating, and optimising with previous rigs.

 

The current digital speaker demonstrates this quite remarkably - close to zero external cables, so the ones left are so much more important to get right; get it wrong, and the drop in quality is subjectively dramatic.

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Noting Yet Another Thrashing about the "significance of jitter",

 

I'm sure that if one went in deep, into the guts of the circuitry, and peered really close, that one could see nasty bits o' jitter wandering around - when the SQ is not up to scratch ... and I would say, "So What?" OK, you've got a possible correlation between what you hear and some measurable, with great effort, misbehaviour - so, what are you gonna do 'bout it ... wave your finger at the circuit, and tell it not to do bad stuff like that?! 😁

 

What I'm saying is that the best approach is to get the engineering, and implementation right up front - and then any jitter will just melt away into insignificance, as far as being relevant to the SQ. I'm pretty sure that the term will have barely passed across the consciousness of any of the designers of the gear I've played with over the years - including the current digital speakers ... yet each setup in its own way has what it takes to get the sound to a good standard - provided the user takes the time and effort to investigate what's possible, 🙂.

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5 hours ago, fas42 said:

Noting Yet Another Thrashing about the "significance of jitter",

 

I'm sure that if one went in deep, into the guts of the circuitry, and peered really close, that one could see nasty bits o' jitter wandering around - when the SQ is not up to scratch ... and I would say, "So What?" OK, you've got a possible correlation between what you hear and some measurable, with great effort, misbehaviour - so, what are you gonna do 'bout it ... wave your finger at the circuit, and tell it not to do bad stuff like that?! 😁

 

What I'm saying is that the best approach is to get the engineering, and implementation right up front - and then any jitter will just melt away into insignificance, as far as being relevant to the SQ. I'm pretty sure that the term will have barely passed across the consciousness of any of the designers of the gear I've played with over the years - including the current digital speakers ... yet each setup in its own way has what it takes to get the sound to a good standard - provided the user takes the time and effort to investigate what's possible, 🙂.

 

Let me fix that for you, Frank: " provided the designer takes the time and effort to investigate what's possible."

 

Jitter, like other distortions, has an effect on sound. Whether or not it's audible is another question. But, proper design, proper PCB layout, choosing the right components, clean power supply, proper shielding, etc. can all reduce jitter to an unmeasurable degree. You, as the user, mucking around with connectors, volume pots, and solder joints, will have much, much less of an effect on jitter than anything a proper design can do, as for example, here:

 

image.png.3ac0e74bb0bd07c820436bc98d67d2f9.png

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11 hours ago, pkane2001 said:

 

Let me fix that for you, Frank: " provided the designer takes the time and effort to investigate what's possible."

 

That's the real long term solution of course - much progress has been made in three decades, but a high percentage of people still complain that digital playback systems are difficult to coax into providing satisfying reproduction under normal circumstances; meaning the user has to take charge to lift the bar. We're not there yet, no matter what the numbers say ...

 

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Jitter, like other distortions, has an effect on sound. Whether or not it's audible is another question. But, proper design, proper PCB layout, choosing the right components, clean power supply, proper shielding, etc. can all reduce jitter to an unmeasurable degree. You, as the user, mucking around with connectors, volume pots, and solder joints, will have much, much less of an effect on jitter than anything a proper design can do, as for example, here:

 

Again, observable jitter is a symptom of a lack of integrity of the system as a whole - noise entering the circuitry via the weaknesses that you mention above either directly cause jitter in a significant place in the system, or effectively distort the signal in the same, subjective way.

 

The current active speaker I'm using has the absolute minimum of connectors, no volume pots, possibly nothing that needs soldering to be involved - and the benefits of that, yes, proper design show through. The raw quality is extremely good, 95% or so in place already ... which means that the impact of any further tweaking is obvious - this is a good place to be, 😁. Would what I'm addressing show up as "jitter" somewhere? Haven't a clue - and, not interested, 😉.

 

If I dropped back to a rig that was choking with problems areas, like the NAD boxes when I first got them, then indeed I would have to resort to all those activities mentioned above, all over again - to get an acceptable standard in place ... the designers back in those days weren't thinking in the ways current ones can; so it was, is necessary for the user to get involved if he wants "what's possible".

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Noting, yet again, that many people in the audio game are absolutely determined that certain areas of an audio rig are absolutely crucial; and that other aspects are only of minor importance. From my POV, they've got it almost completely back to front - say, the need to believe that magnificent measurement figures will automatically deliver top notch sound; but tweaking the quality of the mains power the component sees is not that significant.

 

Every rig I've dealt with has shown that to work in reverse - the latest, digital active speakers, has demonstrated that yet again; quite capable of decent SQ with no tweaking, but to push it into the zone where it becomes "magic" ...  I'll need to address getting the filtering of any rubbish on the mains working at a premium level - something no, current, measuring ever, ever tells you about ...

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Note this reaction to hearing highly revealing transducers ...

 

This is a repeat of the usual problem of hearing a system with elements of very high potential, which is let down by some aspect not being sorted - the closer you get, the fussier you have to be; about everything. The giveaway is the comment,

 

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 I do recall thinking the RAAL’s lacked bass and dynamics and sounded horribly scratchy on top

 

"Horribly scratchy" is what you get when the electronics in the chain have some, possibly very subtle, issue - the high transparency overall is revealing, in all its glory, that which remains unaddressed. Adding some "brilliant!" component, like excellent headphones, is not going to solve this problem for you - you can either dull down the sound, which many do; or, find out what is causing the SQ deficit - and fix it ... the latter method is a top class winner, in every respect 😄.

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Another interesting post,

 

"Slight harshness" is the enemy ... one has to be ruthless in tracking down why one is hearing this; and no, it has absolutely nothing to do with any problems in the recording, 😝 - this is using one's Get Out Of Jail Free card, and avoiding dealing with an underlying issue, or issues.

 

Headphones "relentlessly unforgiving of even the hint of harshness" ... ? Nope ... any rig which is on the cusp of delivering competent SQ will have to endure the same sort of situation - the slightest lack of sufficient integrity, somewhere, will be obvious; and will be intensely annoying because it is so clearly getting in the way of optimum sound.

 

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differences in personal preference? Who knows

 

Not IMO - once one has heard how well some piece of music has come across, that then sets a reference standard for what should be delivered - any experience that is less than that has been degraded by added distortion, from some issue in the playback chain. The choice, as always, is up the user whether he compromises because of some convenience factor that has been gained; or, he decides to go the extra distance to work out a better solution.

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The Edifier speakers I'm currently exploring are ridiculously good for the money ... but they still haven't got the sensitivity to the electrical environment under control ... well, I would be bloody surprised if they did, considering that extremely expensive gear also suffers from this!

 

Which unfortunately means that I have to solve the very same issues that I have had with every earlier rig that I've played with - with a set of expensive components, it's justified to outlay major money to improve the 'robustness'; but it would be damn silly to, say, spend more than the cost of the raw active speakers, just to make them sufficiently bulletproof.

 

What I've gained in this latest experiment is that the integrity of the parts is so high, straight out of the box from the store - so I don't have to do many of the bits and pieces that are normally needed to get around the internal weaknesses ... the focus now is to create a solution for adequately rejecting external interference which is cost effective, that can be packaged nicely - I won't be happy using these speakers on an ongoing basis until I've got them to a place where they can at least always shine as well as they've already shown me they are capable of.

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  • 2 weeks later...

Hmmm, this may take a while to knock over - the sensitivity of the active speakers to the power quality, that is. Because something broke, I had to remove one of the elements used for mains filtering, to repair a physical part - nominally only a minor player in the whole ... the loss in SQ was dramatic! Reinserting that "low level" bit got the quality to snap back ... phew!!

 

This is something that can be quite disturbing, at this level of tweaking - and it's been like this for 35 years ... one seemingly relatively unimportant part of the whole can, for whatever reason, go out of alignment, lose a connection, touch the wrong thing - and the subjective drop in the presentation quality can almost make one panic, ☹️. The good thing is to know that one should then just very carefully inspect every part of the rig, check every tweak carefully - to make sure everything is as it should be ... invariably, something is found - and, order is restored, 😊.

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Ah, the debacle of NBN, our  "fast"  Internet has struck again... Finally, getting the connection happening... and, there's a dud box, somewhere - either the one that came yesterday, inside the house - or on the pole outside. 

 

Will we have to wait a week for any contact to be restored - or will magic happen?... Stay tuned... 

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Well, no NBN magic happened ... the technician who came was a touch nervous, and has now gone AWOL ... no-one, including NBN knows where he is!

 

Which means, yes, will have to wait a week - using USB tethering on a smartphone to prevent having to play with microscopic screens, 🙄.

 

Good news on the current rig - the Edifier digital speakers have passed the John Ireland premiere of Epic March recording test, a BBC broadcast of the 1942 Proms - the corollary is that a modern orchestral track is full, rich, opens up a huge, deep window ...

 

Still haven't touched these on the inside - stabilising cables, mains filtering, and some more intense conditioning have been enough to get a highly acceptable standard.

 

Audio mate up the road has been busy with his old Quad CDP in the shutdown - a note on Facebook tells the story - turns out that the earthing arrangements weren't ideal; and he has done some more finessing of the internals. Very pleased with it now; has lifted its sparkle and life to that of his vinyl, he says - hopefully will catch a listen sometime soon ...

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