02-20-15: Jmcgrogan2
After positive experiences with the HFC interconnects, I finally received a pair of CT-1E speaker cables today. I noticed a dramatic drop in output levels. As Siddh points out, they are quite exceptional, aside from the large drop in gain. However, that may turn out to be a deal breaker for me too. John (and others who are experiencing a similar issue), perhaps the experience Rlawry reported on 1-16-15 involving his HFC phono cables has some relevance: 01-16-15: Rlawry
Previously I reported on this thread that I bought a used 2 meter CT-1 cable to try for signals between my turntable with Lyra cartridge outputting 0.5 mV and my Manley Steelhead Phono Stage. When I replaced my previous carbon nanotube Bybee filter cables with the CT-1 I got no signal at all from one channel and a weak one from the other.... I contacted HF cables and was told the cable connectors were probably contaminated with metallic debris, making for a bad connection, attenuating the weak phono signals. So I sent them back for cleaning and received them today. I tried the cables again after letting them settle for a few hours.
The results were completely different this time, and in a word, otherworldly.... If you think your cables might need the contacts cleaned, HF Cables can send you some Silly Putty to glob onto the connectors to effectively remove the metallic debris. Well under an ohm of contact resistance would be audibly significant in a speaker cable, although several ohms or more would most likely be necessary to cause the 10 vs. 2 o'clock difference in volume control position you described. Also, if you or one of the others experiencing this issue has a multimeter, it would certainly be interesting if you were to disconnect the cable and measure the resistance of each of its conductors between one end and the other. If you are equipped to do that, also check to see if there is an essentially infinite resistance between the two conductors, as would be the case with nearly all conventionally designed cables. Best regards, -- Al |
Wow, John!! No wonder these things sound different, and no wonder they lower the gain of the system.
I would suggest asking HFC if those numbers seem right, or if they are indicative of a defect. If they are correct, and if the 5 ohm impedance spec of your speakers is in the right ballpark for most frequencies and is mostly resistive in terms of its phase angles, it would mean that roughly 2/3 [actually (5.6 + 5.8)/(5.6 + 5.8 + 5)] of the voltage the amp is putting out at any given instant would be dropped across the cables rather than appearing across the speaker terminals. That's a loss of more than 10 db! Although given that you are using a tube amp having a significant output impedance, that would be partially/slightly compensated for by an increase in the amp's output voltage that would occur (everything else being equal) as a result of it seeing a less demanding load of 16.4 ohms rather than 5 ohms.
BTW, how long are your particular cables? As I'm certain you realize, cable resistance is proportional to length, everything else being equal.
And yes, I think it would be well worth trying the 8 ohm tap and seeing how it sounds.
Best regards,
-- Al |
ACman, thanks for providing the additional data point. 3.8 ohms for 2 feet; wow! What kind of speakers are you using? The volume loss resulting from a given cable resistance will, as you probably realize, be inversely proportional to the impedance of the speaker.
In any event, from a technical standpoint a couple of things seem clear to me, assuming that these high resistances are a consequence of the design and not of defects, and assuming that these resistances, which are at a frequency of zero Hz (i.e., the DC that is provided by the meters), are not somehow magically negated at frequencies of 20 Hz and higher:
1)The sonic consequences of the resistance will vary considerably depending on how the impedance of the particular speaker varies as a function of frequency. The output impedance and drive capabilities of the amplifier that is being used will also be relevant factors, meaning specifically that tube amps and solid state amps will tend to interact differently with these cables, and meaning also that due to their differing output impedances different tube amps will also tend to interact differently.
2)Putting aside subjective preferences, those kinds of resistances cannot, as I see it, be considered to be consistent with ***accurate*** transfer of the amplifier's output signal to the speaker's input.
I should add that all of this just applies to speaker cables. Under any reasonable circumstances the resistance of line-level interconnects will be inconsequential, because it will be a miniscule fraction of the load impedance. The same goes for phono cables, aside perhaps for those few situations in which certain LOMC cartridges may be loaded with very low resistances (e.g., tens of ohms).
IMO, FWIW. Regards,
-- Al
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Acman, I'm interpreting that your last post just above was a clarification of the one just above it, rather than an indication of a second measurement at a different point. Is that correct?
If that is not the correct interpretation, you would be saying that you measured the same 13.1 ohms for the speaker itself and for the speaker plus the wires. That would not make sense, given the 8 ohm nominal impedance of the speaker, and also given the 3.8 ohms you measured for each of the conductors in the cable.
If my interpretation is correct, and the 13.1 ohms just applies to a measurement at the amp end of the cable with the cable connected to the speaker, everything seems consistent. The wires total 2 x 3.8 = 7.6 ohms, and the DC resistance of your nominally 8 ohm speaker itself would be 13.1 - 7.6 = 5.5 ohms, which seems reasonable.
Best regards,
-- Al
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Thanks, Roger. That all seems to point to the battery in the multimeter being dead, or possibly to the terminals which mate with the battery being corroded.
In many and probably most analog multimeters the internal battery is just used for resistance measurements, while not being used for voltage or current measurements. If the meter circuits are not receiving a reasonable voltage from the battery, the needle will not move.
Most analog multimeters have a removable cover over the battery compartment, which when removed will provide access to the battery (or batteries).
Regards,
-- Al
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09-18-14: Mapman
... is it possible that both the product and your perceptions are both changing? Not to mention the possibility that something else altogether is changing, in the system or its environment. E.g., ongoing aging or breakin of components, seasonal changes in temperature or humidity (see this post, for example), changes in AC line voltage or noise conditions, etc. As I've said in a number of past threads, in audio it is very easy to attribute a perceived change to the wrong variable. IMO. Regards, -- Al |
Rlawry, I could be wrong but I interpreted John's indication that "my other speaker cables measured ~ 0 ohms" to refer to a completely different set of non-HFC cables. I'm sure he'll clarify, but I suspect he was saying that he only measured the HFC cables on one channel, his "quick check" not including taking the time to disconnect the cables on the other channel. And of course the difference between the two conductors on the one channel was minor (5.6 vs. 5.8 ohms, some of that difference perhaps simply being due to the resolution and accuracy of the meter itself).
Regards,
-- Al
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Strange indeed, John. And I would emphasize that what matters is the total series resistance of both conductors, which would be 11.4 ohms for your 2.5 meter CT-1E, 7.6 ohms for Acman's 2 meter CT-1, and probably less than 1 ohm for Roger's 2.5 meter CT-1U.
Roger, I want to make sure I understand what you mean when you refer to the multimeter needle "barely deflecting." To measure low resistances with most analog multimeters one would set the mode to R x 1 (or some such nomenclature), then touch the meter leads together, then adjust some knob on the meter such that the meter reads 0 ohms, and then make the measurement. The 0 ohm reading will usually correspond to deflection of the needle from its rest position at the left end of the scale, all the way to a position at the right end of the scale where 0 ohms would be marked.
So a resistance of a fraction of an ohm would result in the needle deflecting nearly all the way across the scale, to a point close to where 0 ohms is indicated. Does that all sound consistent with the measurements you performed? If not, I'd be curious to know the make and model number of the meter.
Regards,
-- Al
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02-22-15: Audiolabyrinth
Almarg, How would all these people be able to measure the capacitance of their speaker cable's and Interconect's?, That would be interesteing to know these measurements. Various manufacturers of electronic test equipment offer both hand-held and bench type capacitance meters and "LCR meters" (LCR meters can measure inductance as well as capacitance and resistance). Also, some of the better digital multimeters can measure capacitance, although I suspect that in many or most of those cases the resolution and accuracy of the DMM would not be good enough to make meaningful measurements of cables, when measuring capacitance. And I suspect that capacitance meters and especially LCR meters providing resolution and accuracy suitable for measuring cables are likely to cost at least hundreds of dollars, and perhaps thousands for a really high quality instrument. In any event, regarding the HFC speaker cables I would feel safe in assuming that the capacitance of any speaker cable in which the two conductors are physically separate (i.e., not in the same jacket, and not physically joined together) would be low enough to be insignificant. Inductance is more likely to be important with that kind of cable, especially if cable length is long (since inductance, like capacitance and resistance, is proportional to length), and especially if the speakers happen to be electrostatics (since the impedance of electrostatics typically decreases to low values at high frequencies, while the impedance presented by an inductance rises in proportion to frequency, resulting in that impedance becoming increasingly significant relative to speaker impedance as frequency increases). It's a completely different story when it comes to line-level analog interconnects, btw. With those cables resistance and inductance are usually unimportant, while capacitance can sometimes be quite important, especially if cable length is long and the output impedance of the component driving the cable is high. Regards, -- Al |
However, the part that confuses me is that all HFC cords appear to use the same size conductors, only the magnets get larger as you move up the chain. So being old school, and thinking that more current requires larger gauge conductors has me confused how using larger magnets with the same size conductors can provide the same results of handling higher current. That’s a good question, John, and I certainly can’t provide any insight into what the answer may be despite having looked at the patent a while back. But it seems clear that the gauge and resistance concepts underlying more conventionally designed cables don’t seem to apply here. You’ll recall discussing in the thread some time ago that you and others measured seemingly absurd amounts of resistance for some of the HFC speaker cables, in the vicinity of 10 or 11 ohms for the combined resistance of the two conductors. But nevertheless no one seems to report any issues resulting from that, aside in some cases from having to turn the volume control up higher than when using other speaker cables. It might be interesting, though, to measure the resistances of these power cords, as was done for the speaker cables. Best regards, -- Al |
Bugredmachine 5-31-2016 8:14am EDT
If you’re pulling 10 amps with an amp, that would be some major kilowatts happening!! With 250 watt monoblocks and my full system in play including all peripherals, I only measure around 3 amps total pull at 85 db levels. First, in the absence of further information I would not assume that your current meter is fast enough to capture brief high current peaks in the AC current draw that will occur on brief dynamic peaks in the music, assuming (as I believe) that your TRL Samson amplifiers operate in class AB at high power levels. Second, keep in mind that under typical circumstances most music requires just a small fraction of an amplifier’s power capability most of the time. In general, most of an amp’s power capability is required just for brief dynamic peaks in the music. Third, keep in mind that a musical peak of 95 db will require 10 times as much power out of the amplifier than an 85 db level. For a class AB or class D amp, that means a great deal more AC power going into the amp during a 95 db peak than at 85 db. Roughly speaking, class AB amps tend to be in the vicinity of 50% efficient at full power. So to deliver 250 watts x 2 channels something on the order of 1000 watts of AC would be required, just for the amplifiers. In the USA and other 120 volt countries that is about 8.3 amps. And then there are class A amps, which draw enough AC power all the time to support their maximum output power capability. A Pass XA200.8 monoblock, just to cite one example, is rated to provide 200 watts into 8 ohms and is spec’d as requiring 750 watts of AC. For two monoblocks that would be 1500/120 = 12.5 amps, drawn continuously. Regards, --Al |
