[Steve Eddy]

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif However I do know some instances where specific cables will provide measurable differences and benefits. Example: Tube preamp with high output impedance driving long interconnect cables to monoblock amplifiers. Let's say the preamp's output impedance is 7Kohm - it doesn't have a low impedance output buffer or follower. Interconnect cables are 20 feet long with 100pF/foot capacitance (common for generic low cost interconnect cables). This combination forms a low pass filter at -3dB at 11,370Hz! This WILL be audible.

Sure. But I'm not aware of anyone who would argue otherwise.

The Great Cable Debate has never been about issues of simple resistance, inductance and capacitance. It has always been about other aspects. PVC versus Teflon. ETP versus OFC versus OCC. 99.95% versus 99.999% versus 99.999999%, etc.

se

 

[anetode]

Don't forget the looks, I'm willing to pay extra to make my headphone cable resemble a fluorescent shoelace

 

[Donald North]

I understand what you are saying. You forgot to mention silver

Back to my point: Very few people understand that there are some instances where cables will sound different with legitimate technical explanations.

 

[Steve Eddy]

Quote:

Originally Posted by anetode /img/forum/go_quote.gif Don't forget the looks, I'm willing to pay extra to make my headphone cable resemble a fluorescent shoelace

That can be arranged.

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[Steve Eddy]

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif I understand what you are saying. You forgot to mention silver

No I didn't.

Quote:

Back to my point: Very few people understand that there are some instances where cables will sound different with legitimate technical explanations.

Sure. But generally those aren't the people arguing against cables.

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[roadtonowhere08]

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif Back to my point: Very few people understand that there are some instances where cables will sound different with legitimate technical explanations.

I have a question: is there any case where one would not want the lowest inductance/capacitance cable available?

Your two examples benefit from both attributes being as low as possible. I buy cables with low inductance/capacitance to prevent the possibility of the high frequency low pass filter you mentioned.

 

[Donald North]

Often with cables, efforts to reduce capacitance increase inductance and vice versa. Generally speaker, you want lower capacitance interconnect cables and lower inductance loudspeaker cables.

In efforts to reduce interconnect capacitance, some companies will make unshielded cables. These then can pick up RF/EMI and inject it into your system. If you have a low output impedance preamp/source then this is less of a problem than if you have high output impedance (as in my example).

The lower capacitance & shielded cables I've seen are often large in diameter and not as flexible.

 

[roadtonowhere08]

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif Often with cables, efforts to reduce capacitance increase inductance and vice versa. Generally speaker, you want lower capacitance interconnect cables and lower inductance loudspeaker cables. In efforts to reduce interconnect capacitance, some companies will make unshielded cables. These then can pick up RF/EMI and inject it into your system. If you have a low output impedance preamp/source then this is less of a problem than if you have high output impedance (as in my example).

Gotcha, thank you.

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif The lower capacitance & shielded cables I've seen are often large in diameter and not as flexible.

Yep, those are the kind I have: Blue Jeans Cable LC-1 Low Capacitance Audio Cable. Not all that flexible, but based on the published specs, I am perfectly happy.

 

[anetode]

A discussion of the technical merits of cable design misses the point. The essence of the fancy cable market is the exploitation of consumer psychology. It's the soda pop sold in movie theaters - seemingly a minor component but one with the greatest profit margin and therefore the major source of net earnings. Take some sugar water, a disposable paper cup and license to take advantage of Coke/Pepsi marketing and you have a greater cost ratio than even cables.

Then again, the taste difference between water and pepsi is real and verifiable

 

[roadtonowhere08]

Quote:

Originally Posted by anetode /img/forum/go_quote.gif A discussion of the technical merits of cable design misses the point. The essence of the fancy cable market is the exploitation of consumer psychology.

I agree on the last sentence, but not all do. To delve further down this topic would necessitate a move to a different sub-forum (wink, wink, mods).

Having said this, for those who will not be swayed to either camp, what else is there to talk about? Instead of bicker about beliefs, I would rather learn about the science behind cables. Nothing will change, so why not learn a bit, eh?

 

[anetode]

I suppose so. Forums aren't great places to study the science behind anything other than human interaction

That said, the geek inside me does enjoy all the minutiae of electrical engineering and metallurgy, factual or otherwise.

 

[Lead Ears]

Quote:

Originally Posted by roadtonowhere08 /img/forum/go_quote.gif I have a question: is there any case where one would not want the lowest inductance/capacitance cable available?

Well yeah, if they want a cable that yields audible differences. The first challenge to the pro-cabler is that the audible difference exists, however let's not forget that different ≠ better (at least, not necessarily).

Point being, if maintaining the purity of the audio signal is the goal, then a "good" cable can only harm the signal less than a "bad" cable....a cable cannot add anything to the signal.

On a side note, in relation to Uncle Erik's post at the beginning of this thread, I routinely use a highly sensitive HPLC system in my research (it's an Eicom HTEC-500, for those who are curious). I use it to detect physiological levels of the brain neurotransmitter acetylcholine. My detection limit is down to about 4 femtomoles, which is essentially a 4 picoamp signal. Any lower than that, and the signal-to-noise ratio is unacceptable. Point being, this is a $40k system and it uses regular stranded copper hook-up wire on the inside. It uses a generic IEC power cord, with its own internally regulated power supply (like a best-buy ht receiver). The guy who sold it to us is also one of the designing engineers...if he could sell us a lower detection limit by bundling in a $500 power cord, he would in a heartbeat.

Some of my colleagues do intracellular electrophysiological recordings (in single neurons). They're looking at even smaller signal amplitudes....just regular hook-up wire to the amplifier. The whole electrophys rig is probably over $100k....no expense spared for bleeding edge research, yet regular hook-up wire is good enough....just don't make it any longer than necessary

.

I realize that the "it doesn't show up on the oscilloscope" argument is getting old to a lot of folks, but maybe someone knows what a 4 picoamp signal equals in terms of decibels in a typical high-end listening rig.

Hope this isn't too inflammatory.

 

[Steve Eddy]

Quote:

Originally Posted by Lead Ears /img/forum/go_quote.gif ....a cable cannot add anything to the signal.

Sure it can. Harmonic Technology figured out a way to do that with their CyberLight cables.

se

 

[Lead Ears]

Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif Sure it can. Harmonic Technology figured out a way to do that with their CyberLight cables. se

Yeah, but that's not really a cable, it's a "Light Analog Module (LAM) Photon Transducer Light Signal".

 

[roadtonowhere08]

Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif Sure it can. Harmonic Technology figured out a way to do that with their CyberLight cables. se

Harmonic Technology | Products | Photon Cables | Photon Digital

Wow, over $3,000 to be lied to. How can the music "never be digitized" on a digital cable? It enters the cable as binary data, so right there, they are lying. In addition, they say that there is "absolutely no analog-to-digital conversion". So how does the S/PDIF receiving RCA jack read the data? It can only accept digital data as sent by the source RCA jack. It makes no sense.

I like this sentence: "Musical information is preserved to a greater degree due to complete lack of digitization". The product is called "Harmonic Technology Photon Digital Data Link".

In addition, they contradict themselves with two consecutive bullets:
- Light transmission through the fiber is uni-directional
- Since back reflection is extremely low (< -55dB), optical isolators are unnecessary

More contradictions:

With the signal (pulse) path completely isolated from the ground, the Photon Digital ensures that there is no possibility of the cables passing noise between components, nor acting as an antenna for RFI or EMI induced distortions—keeping the noise floor extremely low and reducing smearing.

Please note: Because there are no physical wires built within the Photon Digital, an extra ground wire may be needed in order to ensure components are on the same ground level.

Finally: True component impedance match for either 75 OHM "RCA"...
No such thing as a true 75 OHM RCA. They would have to use BNC for that... oh wait, they do not offer that