John Curl's Blowtorch preamplifier part II

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Today i listened to Spoon's album "They Want My Soul" first on CD then on vinyl. They sounded a little bit different but not dramatically, which tells me my phono playback system is working pretty well. I can't say I preferred one over the other. The CD is a little cleaner, the vinyl has some positives as well. Of course the LP is brand new, first play today, i doubt it will sound quite so good in ten years. Well made though.
 
I listen to vinyls, but I find modern reviews about that medium are sometimes exaggerated. So just wanted to search if there are any common points raised in favour or against as such in olden days. If there is some truth in pros and cons about both mediums, there ought to be some intelligent far sighted reviewer who may have written about it way back then. 'Which is better' was not my intention. Just wanted to keep things in perspective.

Found some links with general description.
CD Introduction
News story
Regards.
 
Perhaps we are not looking at it the right way? Perhaps vinyl sounds better because more is hidden by surface noise and possibly RIAA correction? Perhaps the problem with CD is that people hear MORE than with an LP? And inevitably, more will include lack of surface noise etc. Less masking.

However, that said, it still leaves unexplained the reasons why some digital players sound wonderful while most sound so-so at best. I mentioned the Philips dream system I was treated with in a demo - left me with confirmed knowledge that excellent CD players could be had now (and "now" was 1992 or '93).

Further, quite by chance, I happen to own two very distinctly different CD players which underline the differences extremely well. My old Yamaha CDX 993 (their top model at the time, unavilable in N. America, no idea why), purchased in 2001, right out of the box sounded extremely "analog", not a trace of the usual complaints associated with CD. At first, I asociated that with the way it was made, twin power transformers, one for digital and another for analog circuits, the fact they use 4 6.800 uF caps to start with and went nuts on local regulation, internal bracing, etc, and later on, when I obtained its Service manual, I could see it was made of a mix of Panasonic and Yamaha chips, basically a tuned MASH machine, but that it used three separate stages for I/V conversion, buffering and a proper output amp. The I/V strage used an op amp, but the following two stages used discrete devices (John, are you reading this?), which seem to have been well thought out, I have seen better but ceratinly way above the norm. IT conveys a sense of presence and if required brutal force (in the bass lines) I don't hear very often. No wonder its predecessor, essentially the same, was well liked by the British press. However, there's a price for everything, while sounding very warm and most "analog", I had a feeling it was skipping over some finer detail. This was later cured by replacing the cheap I/V op amp from NJR with an AD 825, this left the basic sound signature but did produce the lost detail much better.

Then, some years later, I added an outboard DAC I bought from an Australian company, one of the so called "Real Time DACs", based on 8 Philips 1543 standalone DACs in parallel, so no oversampling, no brickwall filters, etc. Its output stage is an AD 847, separate windings and PSU regulation for digital and analog sections. This calmed down the analog sensation, but added still more detail and space. For AUS$ 250, an excellent buy, with second to none service attached. No skimping either, strictly Rubycon caps, Dale resistors, etc. Just add a ase of your choice.

Then, exactly 13 months ago, I purchased my current player, NAD C 565 BEE, which as you probably know uses the Wolferson DAC and a sprinkle of BB 2143 op amps. I don't like NAD, and I never liked the 2134 op amps, but somebody in NAD obviously did serious work and produced a unit in which the result exceeds the simple sum of parts. It really works amazingly (for me) well, the Marantz 6005 sounds distinctly crippled next to it, no contest, NAD wins hands down.

So, obviously, a much better breed of CD players is quite possible at what are still quite reasonable prices, that NAD cost me around damn well spent $450. I even tried using it as a DAC only via an USB cable from the PC, and it certainly made music much more reasonable.

The fact that practically each and every CD will portray soiurce material seems to point towards the way these machines are made. They still have some evolution available to them, taking whatever slant their designers care to aim for.
 
That show that some actually care enough to pay for the higher quality. I think it's rather nice and shows that not all people are seeking the discount department for their foods.

If we really started to care about the quality of replay there just may be the possibility that our hobby starts gaining audience again. As of now, why should any body care. What the younger people hear when they walk into a HiFi shop sounds worse the their Iphone and headset. If this is all we can do, then I understand why our hobby is loosing out. looking in, we're all to blame, as if CD was any of my concern I am making speakers. But it is, we all have and share the responsibility to pull this in the direction of better.

Digital may be convenient, it may be the better source. But its killing music, making people stay at home not going out to buy albums, missing the dialogue with the record dealer recommending albums, digital is assembling all in big super streaming stores killing artists and putting them in their pockets. Digital simply transfers music and audio to computer giants Apple, Google and Microsoft. We should all be behind Vinyl replay not only because it better (I really think it is) but also better for the variety and for our hobby... We all share a responsibility and some people here are quite influential. Let them see the light. and think a little wider than just to their own vertical silo.

My only hope, the light in the night is that with a good system, you can still make people cry, shiver and smile. Whit a good system you can make people want and desire this for their home as well.
 
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Hi Dejan.
What is the brand name of this Aus so called ''Real Time DAC'' board ?.

In my experience/understanding oscillator clock jitter is one of the devils, if not the major devil in the details of digital playback.
Expect some level/spectrum of recording device jitter to be incorporated into CD transfers, and any replay device jitter will intermodulate with this embedded jitter and cause subjectively amplified level of spectral errors.

In the replay device it is not so much the magnitude of the jitter so much as the spectrum of the jitter.
Jitter causes particularly pernicious distortions that are spectacularly unnatural and readily detected by the ear....ie jitter causes a whole spectrum of discordant artifacts that do not occur in nature/natural sounds.

There has been some interesting discussion over on this thread diyaudio - dac-filtering-rasmussen-effect
The OP is advocating fitting a shunt approx 1uf cap ! (I'm not sure exactly which D-S current output DAC) directly across the +/- outputs so as to cause a drooping response of around -1.5dB at 20kHz.
He also advocates use of super-capcitor (ESR = 40 ohms) across the DAC output stage supply in addition to the normal supply decoupling.
The super-cap is I think good advice...provides very effective rail damping down to less than sub audio frequencies.

The HF drooping response claim is an interesting one, more so that Joe states that there is a 'sweetspot' shunt cap value factor involved.
I am interested to try this experiment for myself and hear what Joe is on about.

It could be well argued that none of us old farts can directly hear 20kHz, but I do venture that most of us can hear sub 20kHz artefacts that do not belong, and long term experience with good gear serves to heighten this sensitivity to discordant products.
Good performing vinyl amplification sidesteps playback higher frequency/repetition rate (20Hz +) playback jitter induced problems/artefacts, and I venture this is a major reason why some listeners ardently prefer vinyl over digital.
In my experience, digital done really well/properly kicks vinyl to the kerb in subjective accuracy of cleanliness, depth, side and behind imaging and of course SNR....when the convenience/repeatability of good digital is factored in, digital wins hand down no question.

Dan.
 
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It's due to economics, pcb real estate and designers ignorance...most consumer digital gear to date has the time base quartz oscillator crystal directly connected to two pins of the system DSP.
This is exactly how not to do it, rendering the audio stage oscillator prone to all sorts of system induced modulations, and the now standard DDS techniques only serve to worsen the (jitter) situation.
Take a closer listen to your mobile phone for instance....the playback jitter is very much broadband and casts a broadband (white/ish) noise over the final audio output, markedly reducing ultimate intelligibility.

Dan.
 
Max, I think I told you already, I'd love to give you a link as these people deserve it, but cannot because their address ws on a hard disk I lost.

Google for things like DIYAustralia or some such, that's how I ran across them the first time. Since the whole process was via the Internet, I have unfortunately and stupidly lost all comms with them.

On the other hand, looking over the seemingly endless list of Chinese suppliers, I did see a few offerings which looked like spitting images of what I have, but of course, for less money. Leads are outboard DAC, Real Time DAC, etc.

I'll give it another go, but don't hold your breath.
 
MiiB, if your comment is related to me, I have always known that there's no such thing as a free lunch. If you want quality, you will have to pay, but unfortunately, having to pay does not guarantee quality any more. THIS is I think one of the key reasons why our beloved hobby is losing ground, to many snake oil peddlers around.
 
Or Marketing.

Hipster fashion and social signalling. First, let's put it in perspective- sales have grown from microscopic to minuscule. The growth in downloads in one day is larger than the growth of LPs in a year. Second, what's the fastest growing hardware category on this anthill growth curve? Yep, USB turntables!

We were at a concert last night, one of our favorite musicians. He had his new CD on sale, and vinyl as well. "People kept asking me to release stuff on LP, so I had some pressed." "Same recording as the CD and the download?" "Yes." "Do you think it sounds better?" "Who cares, the important thing is that people who want my music can get it."

So... the people buying that LP were buying a digital recording, just one that was sold on an inferior medium that has fun and ritual associated with it. And that seems to be true more often than not; all of the musicians I know who have released LPs recorded and mastered them digitally. But that's fine, their audience is getting the music. The hipsters have the "cool" and the ritual, and the download sales still overwhelm everything else.

And it was a great show.
https://www.youtube.com/watch?v=aYjqfYd_HSE
 
MiiB, if your comment is related to me, I have always known that there's no such thing as a free lunch. If you want quality, you will have to pay, but unfortunately, having to pay does not guarantee quality any more. THIS is I think one of the key reasons why our beloved hobby is losing ground, to many snake oil peddlers around.
Yep, far too much BS involved, witness many recent esoteric CNC produced designs that look great/fantastic and fit perfectly in modern decor, but ultimately miserably fail to deliver acoustically, and at stratospheric price points.
Just combine a CNC oriented engineer with cloth ears/ignorance and a Persian carpet salesman marketing department and you have modern 'high end'.

Dan.
 
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