Are anyone using Fulton wire length in their speakers, interconnects or power cables? I am planning to build my power cable and interconnects with this length which is 114 1/4 th inches or 57 1/8th inches long (tip to tip not including any connectors). This length was discovered in the 1970s by Rob Fulton to have minimum reflection of signals back to source. Was wondering if anyone tried this before and their listening impressions vis-a-vis other lengths.
Fulton Length Wires
- Thread starter Hari Iyer
- Start date
panditji
Well-Known Member
Waiting to hear your impressions .. This should be interesting if you find any difference...
kapvin
Well-Known Member
very interesting bit of Arcania. but if it were a more secularly heard difference, it would have found its way into other equipment in the 45 years since its discovery. More likely a more select group only can hear the difference.
I just love @Hari Iyer 's ability to pull out such interesting yet arcane stuff. always entertaining, and sometimes informative
kapvin
Well-Known Member
wow!Shun Mook cables use this lengths and charge a fortune.
but I am sure that there must be more to their claim than just precision cutting. or people would take the cheaper model and "upgrade it" with a few snips.
As far as I know Kapvin, they use tinned copper cables, probably Western Electric, and then package them and sell them. Maybe they add something to the cables or treat them with something. I have no clue. Most of these audiophile tweaks and cables use stuff like quartz crystals, amethyst powder, etc, which all have piezo electric properties and help in reduction of emi and rf.
I was Mr. Robert Fulton's friend and so-called special Southern California representative, from 1980 until 1984. To my own knowledge, his special lengths were never tested subjectively, on a reference - quality audio system, until 2020. Forty two years after his death.
Mr. Dennis Fraker, who owns a company called " Serious Stereo " did such testing on his own home system. A top-notch set up. He subjectively determined that indeed, 57 1/8th WAS the best sounding basic audio length. What I had taken as good faith, as Mr. Fulton's word, for 46 years, was indeed finally confirmed to me subjectively, in 2020.
Very interestingly, Dennis determined while experimenting, that two Fulton lengths in series, ( 57 1/8th Xs two or 114 1/4 inches ) sounded better to him, than a shorter single length increment. Not only for speaker leads, but for Power Cord lengths also. Pierre Sprey, recently deceased owner of Mapleshade Audio, determined that an 8 foot speaker cable length, always sounded better to him, than any 4 foot length speaker cable.
The Japanese high end company Shun Mook that Prem mentioned " got this somewhat right . Length selection was done according to their web site " purely by critically listening ". 0ne of their length offerings is " 14 feet ". Fourteen feet times 12 inches is 168 inches. If we divide 168 inches by three, we obtain 56.00 inches. Wouldn't one have to say, that there exists a striking similarity between 56 inches - determined subjectively, to Mr. Fulton's 1970s 57 1/8th inches- objectively ( lab ) determined length ?
To this day, I incorporate Fulton lengths in my audio system, typically multiples, sometimes divisors. Mr. Robert Fulton also lives on, forever in my heart.
Jeff
Mr. Dennis Fraker, who owns a company called " Serious Stereo " did such testing on his own home system. A top-notch set up. He subjectively determined that indeed, 57 1/8th WAS the best sounding basic audio length. What I had taken as good faith, as Mr. Fulton's word, for 46 years, was indeed finally confirmed to me subjectively, in 2020.
Very interestingly, Dennis determined while experimenting, that two Fulton lengths in series, ( 57 1/8th Xs two or 114 1/4 inches ) sounded better to him, than a shorter single length increment. Not only for speaker leads, but for Power Cord lengths also.
Pierre Sprey, recently deceased owner of Mapleshade Audio, determined that an 8 foot speaker cable length, always sounded better to him, than any 4 foot length speaker cable.The Japanese high end company Shun Mook that Prem mentioned " got this somewhat right . Length selection was done according to their web site " purely by critically listening ". 0ne of their length offerings is " 14 feet ". Fourteen feet times 12 inches is 168 inches. If we divide 168 inches by three, we obtain 56.00 inches. Wouldn't one have to say, that there exists a striking similarity between 56 inches - determined subjectively, to Mr. Fulton's 1970s 57 1/8th inches- objectively ( lab ) determined length ?
To this day, I incorporate Fulton lengths in my audio system, typically multiples, sometimes divisors. Mr. Robert Fulton also lives on, forever in my heart.
Jeff
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I remember reading about a Theory for Digital SPDIF signals where 1.5 m was supposed to be the ideal length as anything shorter than that had some reflections which messed with the sound. If i remember it had to do mainly with managing the 75Ohm input and output impedences which the SPDIF format was designed around.
Not sure of there is a corresponding theory for speaker cables ?
Not sure of there is a corresponding theory for speaker cables ?
Most interesting arj. Good posting.
I recall, in the late 1979, Mr. Fulton telling me that one meter was not a good cable length at all, something then-prevalent, which he disliked..
But you are quoting us 1.5 meters.
One point five meters ........... converts to 59.05 inches.
59.05 inches and 57.125 inches that Mr. Fulton determined, are only about 3.4% apart. Not too different .
Thanks !
I would speculate that Mr. Fulton's wire work resulted when Fulton was called in by the Psychological or Physiology ( ? ) Lab, at the University of Minnesota. They were audio - testing animals with good high frequency hearing. Lab animals, baboons, at about 20K. When they switched to 60K signals, all the Lab's test animals, ( each which had been carefully documented ), got sick. Robert Fulton, as an audio consultant, came to the Lab's rescue.
Recall his biography " a guy who can fix anything " ?
Jeff
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The principle is the same for light as well as electricity which are both electromagnetic waves travelling at a constant speed, regardless of the frequency or wave length but depending on the medium through which it is travelling. In vacum this speed is 299792458 m/s. The speed of any electromagnetic wave cannot change regardless of the frequency, else you will violate Einstein's theory of relativity. So what happens to light when it travels in one medium with imperfections, it changes direction, rather than changing speed. In an optical fibre this will cause optical reflections. These reflections are fully explained by Fresnel's equations. These equations are furhter based on interface conditions for electromagnetic fields and maxwell's equations. When electricity passes through circuits having differing impedance it is exactly like light passing between two mediums with different refractive index. In case of electricity, the equivalent is impedance. But this phenomena even for electical signals are called reflections because they are exactly like what happens with light.
A perfect optical cable is one that has no imperfections to reflect light inside the cable. A perfect electrical cable is one which has zero resistance, zero capacitance and zero inductance. None of which is possible in real world.
When you are passing electricity through a wire, the wire is a series of infinite inductors and resistors in series and infinite capacitors in parallel. When the amp passes signal, it charges the first capacitor, then the second and so on till it reaches the end. If the circuit is open, the last capacitor charges with voltage more than the rest of the line capacitance. But the last capacitor is connected to the previous capacitor, so it charges the previous capacitor and so on and a positive wave travels back to the amp as a positive reflection wave. If the wire is shorted at the end, the last capacitor cannot charge. But it is has another capacitor before it, so it will discharge that. This discharging of capacitors then travels back to the source (at the speed of EM propagation) as a negative voltage reverse wave that cancels out the forward positive wave.
Somewhere between open and short is a nice medium value of impedance which doesn't allow overcharging or undercharging. Thus leaving no change in voltage to propagate back along the transmission line. That terminating impedance just happens to be the characteristic impedance of the transmission line, which is determined by the distributed capacitance and inductance of the wire, the speaker and the amp output, pcb trace, transformer connected to amp output, etc.
This is where I'm not clear. I think amps are designed for specific impedance of speaker (4 ohms or 8ohms generally) plus some impedance of the speaker wires. Or they are designed with the expectation that the speaker wire will have infinitesimally small impedance.
The importance of matching impedance
Understanding Reflections and Standing Waves in RF Circuit Design | Real-Life RF Signals | Electronics Textbook
Read about Understanding Reflections and Standing Waves in RF Circuit Design (Real-Life RF Signals) in our free Electronics Textbook
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Hi,
Neat explanation. V.G., even I followed you. How do you come to know all of this?
I used to explain things to audiophiles decades ago as
" We all go ape over these speaker wires ". IMHO, power supplies that you mention differ vastly, amp to amp, in tube amps, depending upon it's design and implementation.
I am thinking in terms of a full blown L.S.E.S. supplies, with 5 uF GTO bypasses for C1 and C2 to the Finals, and
other conventionally- designed tube amp power supplies. The L.S.E.S. topology drives the heck out of speaker wire, and speakers.
Even a SE output transformer's Z mach, becomes less of an issue.
Jeff
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At the risk of going off topic, but the principle of reflections should apply to power supplies too.Hi,
Neat explanation. V.G., even I followed you.
I used to explain things to audiophiles decades ago as
IMHO, power supplies that you mention differ vastly, amp to amp, in tube amps you use, depending upon it's design and implementation.
I am thinking in terms of a full blown L.S.E.S. supply, with 5 uF GTO bypasses for C1 and C2 to the Finals, and
any conventional tube amp's power supply. The L.S.E.S. drives the heck out of speaker wire, and speakers.
Even the SE output transformer's Z mach, becomes less of an issue.
Jeff
Ultimately what we hear from the speaker is the power supply. The power supply has a challenging job with an output whose impedance keeps on changing depending on the frequency of the signal at the moment. How do amp designers take the abiity of the power supply to provide constant DC output without causing any reflection? Do they assume putting a large bank of capacitors will be enough? Can regulated power supply be used? Can a regulated power supply be as fast as the ability of the capacitors to provide power during peak demands? My guess is the regulated power supplies even today cannot beat the speed of capacitors, but that's my guess and I have no knowledge about how fast regulated power supplies can be or if they are used in demanding amps.
I totally get it. The way I understood power is that if you consider music as a piece of sculpture then the power supplied to the amp is the Raw material and the amp itself is the sculptor
The input signal is the small image which needs to be reproduced bigger and the amp (sculptor) carves it on the input power ( Material) to give it to the speaker. The better the material, the better the output and hence the importance of the powersupply to the amp. And this is valid for every component that has some sort of an amplification etc preamp/output stage etc.
This means of getting this power being so critical better be well designed.
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I don't want to go too deep into it as it is a subjective topic and best to be tried and guaged.
Techincally speaking, the impact of reflections apply only to very high frequency transmissions that are to be transmitted over very long distances and do not impact audio frequencies.
In RF applications, reflections are usually taken care by matching the source and load impedance.
Other than reflections, another problem that will surface is standing waves, a mix of transmission and reflection waves which can lead to vagaries in amplitude. While some may cancel out others will add up causing higher voltage at the load than the source.
But as I have stated in the 1st para, their impact is way below negigible for normal audio applications.
With digital transmissions, the 75ohm charatcterestic impedance is the reason for the minimum 1.25 meter cable length suggesstion, but that again applies only is very realisistic situations. I persoanlly have not heard any audible impact of this with coax cables, have used 50cms to 3 feet cables.
The length I use is determined by the need depending on component distances to avoid clutter.
Techincally speaking, the impact of reflections apply only to very high frequency transmissions that are to be transmitted over very long distances and do not impact audio frequencies.
In RF applications, reflections are usually taken care by matching the source and load impedance.
Other than reflections, another problem that will surface is standing waves, a mix of transmission and reflection waves which can lead to vagaries in amplitude. While some may cancel out others will add up causing higher voltage at the load than the source.
But as I have stated in the 1st para, their impact is way below negigible for normal audio applications.
With digital transmissions, the 75ohm charatcterestic impedance is the reason for the minimum 1.25 meter cable length suggesstion, but that again applies only is very realisistic situations. I persoanlly have not heard any audible impact of this with coax cables, have used 50cms to 3 feet cables.
The length I use is determined by the need depending on component distances to avoid clutter.
mbhangui
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RIGHT ON, in your above post. Good.
Off topic possibly, but power supplies rule, and they also BEG to be well wired !!
** I have been waiting patiently two years on HFV, for a F.M. who is from India, to eventually bring up such things ! **
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
I have DIY build experience with regulated supplies, for tube amps. My 1982-84 ( Fulton topology design -assisted ) monoblocks. Each had L1/C1/L2/C2 passive supplies, 24 Ohm DCR Ls, followed by double actively solid-state regulated B+ supplies, separate for the Input stage, the Driver stage, and Finals stage. The filaments were actively regulated.
The problems were, each channel was FAR too large. Each required three chassis, and was FAR too heavy, do I recall 350 pounds per channel or maybe in total. The solid state B+ regulators blew up regularly, due to my lack of solid state E.E. experience . The amp was great, when it was running. Ten 6SN7-GTBs with a 612 VDC B+ supply, cap coupled into six P-P-P 6B4-Gs per channel, with no NFB loops. My first tube amp design ever.. One channel here :
Today, I can beat that 1982 amp's performance, with a 100% reliable 57 pound single chassis stereo amp using an all passive supply, and Tetrode 6005 Finals.. Or, .... as two 43 pound 9 Watt monoblocks ( the 6005 TRIPLE ).
Very respectfully, your ideas of capacitors , and large sizes, has been proven to be incorrect thinking in terms of topology over the last 30 years, by " hep " DIY builders I associate with. To explain : The lager the capacitor bank, the slower, and more out of time, the amplifier becomes. A large capacitor bank plays the music back in the slow time of that large reservoir. NEVER ever in the time of the music. It becomes absolutely 100% incapable of supplying a Final tube's PEAK instantaneous requirements. As such, it is thus very poor at pulse reproduction. Music IS complex pulses, ever- changing. The tube amp's power supply must be designed to be just as fast as the audio circuit, that it feeds !!!
Kindly allow me to cut and paste Dennis Fraker, my audio Mentor's few words :
The above paragraph is an excellent conceptual explanation of why we use a L.S.E.S. supply topology. Thanks for getting this. Anyone may ask any responsible questions !!
Jeff
................................................
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
RIGHT ON, in your above post. Good.
Off topic possibly, but power supplies rule, and they also BEG to be well wired !!
** I have been waiting patiently two years on HFV, for a F.M. who is from India, to eventually bring up such things ! **
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
I have DIY build experience with regulated supplies, for tube amps. My 1982-84 ( Fulton topology design -assisted ) monoblocks. Each had L1/C1/L2/C2 passive supplies, 24 Ohm DCR Ls, followed by double actively solid-state regulated B+ supplies, separate for the Input stage, the Driver stage, and Finals stage. The filaments were actively regulated.
The problems were, each channel was FAR too large. Each required three chassis, and was FAR too heavy, do I recall 350 pounds per channel or maybe in total. The solid state B+ regulators blew up regularly, due to my lack of solid state E.E. experience . The amp was great, when it was running. Ten 6SN7-GTBs with a 612 VDC B+ supply, cap coupled into six P-P-P 6B4-Gs per channel, with no NFB loops. My first tube amp design ever.. One channel here :
Today, I can beat that 1982 amp's performance, with a 100% reliable 57 pound single chassis stereo amp using an all passive supply, and Tetrode 6005 Finals.. Or, .... as two 43 pound 9 Watt monoblocks ( the 6005 TRIPLE ).
Very respectfully, your ideas of capacitors , and large sizes, has been proven to be incorrect thinking in terms of topology over the last 30 years, by " hep " DIY builders I associate with. To explain : The lager the capacitor bank, the slower, and more out of time, the amplifier becomes. A large capacitor bank plays the music back in the slow time of that large reservoir. NEVER ever in the time of the music. It becomes absolutely 100% incapable of supplying a Final tube's PEAK instantaneous requirements. As such, it is thus very poor at pulse reproduction. Music IS complex pulses, ever- changing. The tube amp's power supply must be designed to be just as fast as the audio circuit, that it feeds !!!
Kindly allow me to cut and paste Dennis Fraker, my audio Mentor's few words :
The above paragraph is an excellent conceptual explanation of why we use a L.S.E.S. supply topology. Thanks for getting this. Anyone may ask any responsible questions !!
Jeff
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F.M. Yogibear's ( above ) post :
" Well, I thought the shortest signal path is best for faithful reproduction of music. Above lengths would make my set up real messy. "
We have precedents here in this thread, such that your first sentence's statement is not really 100% so :
1) Mr. Fulton's Audio Lab wire work for sickened baboons in the 1970s.
2) Pierre Sprey's web site, where he most clearly advises NOT to use a shorter speaker wire length, in all instances eight feet being superior sounding to four feet.
3) Dennis Fraker's subjective listening tests in 2020, where for both power cords and speaker leads, he determined 114 1/4 inches clearly sounds superior to 57 1/8th inches.
Shun Mook "somewhat" comes into play, in a somewhat less precise way. As was arj helpful, with a 1.5 m SPDIF " ideal " cable length.
Very interesting, eh ?
Inside amps and preamps Yogibear, I agree with you - " shortest possible and also equal lead lengths " rules.
Sometimes internally we can apply a divisor of 57 1/8th, like seven plus inches ( one eighth ).
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Observe this 2022 RCA jack to Input tube's Grid #1 ( control grid ) wiring, low loss, equal lengths and double Wonder Wire :................................................... ( the 2021 Chassis #2 stereo 6005 amp )
short run above, with high transfer efficiency.
Jeff
" Well, I thought the shortest signal path is best for faithful reproduction of music. Above lengths would make my set up real messy. "
We have precedents here in this thread, such that your first sentence's statement is not really 100% so :
1) Mr. Fulton's Audio Lab wire work for sickened baboons in the 1970s.
2) Pierre Sprey's web site, where he most clearly advises NOT to use a shorter speaker wire length, in all instances eight feet being superior sounding to four feet.
3) Dennis Fraker's subjective listening tests in 2020, where for both power cords and speaker leads, he determined 114 1/4 inches clearly sounds superior to 57 1/8th inches.
Shun Mook "somewhat" comes into play, in a somewhat less precise way. As was arj helpful, with a 1.5 m SPDIF " ideal " cable length.
Very interesting, eh ?
Inside amps and preamps Yogibear, I agree with you - " shortest possible and also equal lead lengths " rules.
Sometimes internally we can apply a divisor of 57 1/8th, like seven plus inches ( one eighth ).
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Observe this 2022 RCA jack to Input tube's Grid #1 ( control grid ) wiring, low loss, equal lengths and double Wonder Wire :................................................... ( the 2021 Chassis #2 stereo 6005 amp )
short run above, with high transfer efficiency.
Jeff
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You state "Sometimes internally we can apply a divisor of 57 1/8th". If so, that should make Yogi Bear and many other members of this forum very happy. But that's only so if the divisor applies to external wiring as well as internal wiring. .If not, that leads a multitude of reasonable and common-sense questions such as 1 )what's the difference? 2) exactly what are those "sometimes"? 3) do you have any evidence to support your claim or is it just something that you have simply made up? etc., etc., etc.
Without getting into the specifics, which would literally require a doctoral dissertation, your statement "Very respectfully, your ideas of capacitors , and large sizes, has been proven to be incorrect thinking in terms of topology over the last 30 years, by " hep " DIY builders I associate with. To explain : The lager the capacitor bank, the slower, and more out of time, the amplifier becomes. A large capacitor bank plays the music back in the slow time of that large reservoir. NEVER ever in the time of the music. It becomes absolutely 100% incapable of supplying a Final tube's PEAK instantaneous requirements. As such, it is thus very poor at pulse reproduction. Music IS complex pulses, ever- changing. <deleted>
In my opinion, the proper way to think about this issue is in terms of power supply output impedance, which is a measure of how much the power supply voltage varies when subjected to a dynamically time-varying load. In my experience, active voltage regulators are able to provide a low impedance only up to a few kHz. In order to provide a low impedance at higher frequencies, you need capacitors. More importantly, rather than a single large capacitor, you need a bank of parallel capacitors, each of which has a self-resonant frequency that is much higher than the highest frequency that the amplifier is expected to produce. My 2 cents.
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surfatwork
Well-Known Member
Sometimes, the desire to do something different just because one can, overtakes the need to do something because it makes an objective difference.
After that, it is simply an exercise in self-justification.
After that, it is simply an exercise in self-justification.
Subbu68
Well-Known Member
Very true..
Transmission line theory to my knowledge applies to long lines and lossless lines. When you have like 2-3m ?????
BTW we do use it for power lines too for surges.
Very important point you made. I did some reading and find that unless you reach frequencies in Mhz, Ghz range, reflections are too tiny to cause any effect. I didn't have a idea of the amount of reflection that would be present for audio spectrum. But it was in my mind because of these claims from a company like Van Den Hul and others warning the users how harmful reflections are and how their cables eliminate that. I have first hand experience with VDH revolution cable which I use it to connect my speaker and which i discovered has the superb property of imitating an ordinary 12 awg lamp cord.
Just one excerpt on reflections
Indeed most of these companies peddle snake oil.
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