Do CD Transports benefit much from upgraded power cords?

@vuch

the question was about power cords!

@audiophile1 

Not to mention the likelihood that the CD transport injects noise onto the power cord which can affect other components.

A CD transport includes three feedback loops: a servo mechanism for adjusting the height of the laser above the pits on a rotating disk; a control system to regulate the flow of bits by slowing down the rotational speed of the platter; and a mechanism for tracking the pit spiral towards the outer edge of the disk. Most likely these are realised digitally.

Then there is the digital logic to apply the Reed Solomon Error Correction Code.  Altogether quite an electrically noisy environment!

Interestingly I have access to a couple of Sony universal disc transports, which handle CD, SACD, DVD, BluRay and Ultra BluRay.  Each transport has two HDMI outputs, one purely for audio.  

Each is powered by a 12-Volt wall wart, so it would be very easy to substitute a 12-Volt car battery for the mains supply and do some A / B comparisons.

What objections are likely to be raised by the community, a) if there is no clear audible difference or b) if a clear audible difference is reported?

@thecarpathian 

"Doesn't amperage play a part in this? I also don't see the correlation between changing the power source with changing the power cord"

Many of us have to make do with 240-Volt mains supply, so already need less than half the amperage of the 110-Volt crowd!

I am proposing an experiment where an AC mains power supply (which happens to be external to the transport and converts AC to 12-Volt DC) is replaced by a 12-Volt battery.  The AC power cord is not just changed, it is completely removed.  The mains AC, with all its alleged noise, is also completely removed.  If need be, the battery and the low voltage cable can be shielded by a Faraday cage.

12-Volt Amperage consumed by the transport would be unchanged, and quite small.

Personally, I would expect the output from the transport, as delivered via HDMI, to be indistinguishable at the bit level.  But there may be an impact on other components from the removal of the wall wart (switched mode power supply).  Not bought from Walmart!

Earlier I proposed an experiment to replace a switched mode power supply delivering a nominal 12-Volts DC for a 12-Volt battery in a Faraday cage. The target CD transport is a Sony Univeral disk player with HDMI output.

My Windows laptop has an HDMI connection.  Does anybody know how to capture CD playback on this HDMI connection to a digital file on the laptop.  If so, this should be able to tell if there is a bit-wise difference between power sources when playing back the same CD.  Assuming the same starting position!

If the two match bit-wise, any sound quality difference would surely have to be caused by the injection of electrical noise into other connected components by the switched mode power supply.

Obviously, if I do hear a difference, I have satisfied one person (me) that there is a difference, especially if I hear it consistently in a blind comparison.

But I can also hear the objections.  My mains is about 250-Volts RMS, not 110. My grid is not like yours.  (Mine is geographically the world's biggest, going from the Northern tip of Queensland south down the Great Dividing range then under the ocean to the hydro-electric generators in Tasmania).  There's no big industry near where I live, only an electric light rail several miles away, Even the ultra-low frequency submarine communications base has been dismantled.

If I can't hear a difference, the CD transport will be too cheap, or my ears too old, or the rest of my gear too unresolving.

Thoughts?

@thecarpathian

"Perhaps not permanently..."

The three huge radio towers have gone, and there are houses there now. I do know a street in Canberra where all the houses have been vacated by order because of high radiation risk. Did not stop us working the other side of the road, in clear sight of numerous defence satellite dishes.

I do have an absolute example where modifying a power cord causes a digital signal to become unintelligible. I have a KEF subwoofer in my motorhome which can be powered by mains, or via a battery and inverter. When switched on, with the standard power cord, the class D amplifier in the KEF generates so much RFI down the power cord, it stops my TV receiving digital signals over-the-air.

Modify the power cord by adding two ferrite chokes and the RFI becomes benign. This is entirely objective, and repeatable. No subjectivity required!

My take: stop worrying about the noise coming in from the mains, start worrying about the noise your components might generate

In my youth, when I could only afford 20 for a bottle of scotch, I thought they all tasted about the same. Later in life I graduated to single malts 5 to 10 times more costly. Each year, we stopped blind tasting wine and did a whisky tasting. All we had to go on were tasting notes, because even the bottles had been exchanged to remove that clue. Bottom line is that I correctly identified all eight whiskies presented. One was 16-year old Lagavulin with its signature iodine, seaweed and hospital bandage aromas.

We blended the left-overs. Lagavulin dominated the blend ... and it is now my favourite drop. As a treat, my partner bought me a bottle, but sadly it was only 8 years old and a pale shadow of the older stuff.

I believe that, unlike wine and even beer, whisky does not change once it is bottled. I can see no reason why a single malt cannot be improved with a little blending - I am looking at a very rare Tasmanian double malt as I type. Like hifi, a law of diminishing returns comes in until like a painting, the value is in the rarity, not the picture ...

@mclinnguy

The guy who organised the whisky tastings was very quietly spoken and must have had pretty good hearing. He was an SAS instructor, and his reputed specialty was to disarm a knife wielding attacker while he was unarmed AND BLINDFOLDED. He used to spend weeks living off the land in the Northern Territory, observing joint US and Australian exercises while remaining unseen.

Another attendee knew a lot about transports - he flew Hercules including the final humanitarian evacuations from Saigon. Ended up as Wing Commodore for the RAAF’s VIP fleet

But I digress ...

@audphile1 

Johnny Walker blends malts all the time.  Blue Label includes Lagavulin ...

The real crime in my book is adding ice

My point is that a tiny dram of another whisky has a chance of improving the single malt, which itself is likely a blend of many barrels,

Bit like changing a power cord on a CD transport really

Anyone know what happens when you bend a single crystal wire?

My metallurgical training would suggest the single crystal would morph into multiple crystals, or grains. It is called work hardening. Grain boundaries increase resistance.

Unlike other crystals, metal crystals often have an extra half-sheet of atoms which allows the crystal to 'slip' and plastically deform way below the breaking point of brittle crystals. The purer the metal, the easier it slips and the softer it is.

@thecarpathian

You asked in my opinion what "is the best type copper for cable application?".

I am here primarily to learn, so really I am the worst person to ask!  However my physics background forces me to apply Occam's razor to claims.  If there is a simple explanation, it is more likely to be correct than a complex one.  Or as Einstein said, make the explanation as simple as possible, but not more so.

To your question: Theoretically, for high voltage transmissions lines, aluminium is best with a steel core to hold it up.

For microwave frequencies, use hollow pipes because of the skin effect.

For speakers, usually a high current application, the shorter the better.  Ideally the amplifier is in the speaker so its output can be feedback-corrected to match the speaker.  Otherwise you probably want low resistance in the cable and the connectors.  If you halve the length, or double the cross section, you halve the resistance.  Note that all speakers have varying impedance across their frequency range, especially around cross-over regions.  Changing the resistance of the cable will alter the tonal balance, for better or worse.  Changing the purity and crystal structure only have small effects on resistance.

The mere act of changing a cable scrapes oxidation from its connector surfaces, and suddenly the resistance drops a bit.  The speaker gets a bit louder and louder sounds better.

In practice, most of my cables are cheap!  I did buy one slightly up market power cord but I cannot find it.  I did modify one power cord by adding ferrite chokes to mitigate RFI emissions and that solved a particular problem.  I still feed my Quad electrostatics with the Naim speaker wire my dealer threw in forty years ago.  I re-terminate it every few years.

When I bought current-hungry KEF Reference 1 speakers I bought a pair of QED silver coated copper leads with a fancy twist, secondhand.  I could bi-wire them but can't be bothered - still enjoying them too much.

I did buy some van den Hul balanced interconnects, because the blurb on their website made some sense from a physics viewpoint.  They use the cable weave invented by Alexander Graham Bell.

Am still seeking advice on rewiring my old SME tonearm!  Reducing the number of corroded connections and going balanced has some appeal!  Siver litz or copper?

My digital connections are all HDMI, no dramas as long as they include Ethernet. I only stream audio in order to sample tracks, and then it is WiFi to my phone and Bluetooth to my pre-amplifier.

Basically a cable sceptic but so many report benefits, they can't all be wrong.  Can they?