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Signalkabel and your characteristics
The electrical music signal consists of a mixture of rivers (electron movement) of different frequency (5 Hz-100 kHz) and amplitude (1 well - 1 mA and/or with loudspeakers to 10 A), which must at the same time pass (in correct temporal relationship = phase) the cable.
Periodical parameter:
Every time two leaders to be parallel led a parallel capacitance C develops (in pF/m). Stromdurchflpossene leaders thus always develop a magnetic field and a longitudinal inductance L (in µH/m). These provide for a nonlinear envelope delay within the transmission range (approx. 5 cycles per second - 100 kHz), i.e. signal stream of different frequencies need different times around the cable to happen. Hence that impulses are worn, the rendition follows inhomogenously and the spatial illustration becomes indistinct. A further periodical phenomenon contributing to it is the skin effect. In a leader current portions with high frequencies are pushed to the surface of the leader, this lead likewise to envelope delay distortions.
Frequency-independent parameters:
(Approximately) the frequency-independent characteristics of a cable are the longitudinal resistance R (in mOhm/m) and the parallel conductance G (in µS/m). They represent the dissipation factors (Dissipations Factor) of the line (Ds=R/Omega*L and Dq=G/Omega*C), which should be as small as possible together with L and C. To neglect thereby the losses of the insulator (dielectric) are not infinitely high that, and is more exactly regarded also not frequency-independent!
The insulator is permanently in the electrical alternating field (between the two leaders, Poland). The molecules of the insulator are moved with the field change (pole reversal) and polarized thus (material-dependent dielectric constant). These material shifts withdraw from the music signal energy (dielectric dissipation factor) periodically, since this procedure cannot run off infinitely fast.
Polyethylene (SPE), usually foamed, teflon (ptfe) and air is suitable, there the dissipation factor (tangent delta) small and hardly a capacity increase took place as dielectric very well (this is desired only with the element condenser). The insulator PVC frequently used with cables is conceivably badly suitable. The dissipation factor is high, the free electrons of the material provides for zero crossover distortions, the leader chemically is attacked (free hello genes), but it is economical. Foamed Polyuretan (PURE), which in inexpensive Coaxkabeln is often used, is a good compromise.
Exotic Isolationen is manufactured from silk or untreated cotton.
By suggestion of the cable with sound a modulation finds instead of (Mikrofonie). I.e. the opposite ladder can be moved in the distance to each other in the clock of the music slightly, which leads volume-dependent modulation of the signal to the change of capacity and thus to frequency and.
The technical data:
With Interconect cables the capacity is with approx. 50-100 pF/m (in exceptions until approx. 1000 pF), the Induktität in the Größenordung of 0,3-1 µH/m, the resistance with 20-100 mOhm/m the conductance with approx. 0.01-1 µS/m (the conductance Siemens is the reciprocal value of the resistance). The characteristic impedance can be computed from L and C:
Z = root (L/C), e.g.: L=0.4ΜH, C=70pF - > Z=75Ohm.
With loudspeaker cables inductance should not exceed 0.1-0.5 µH/m and the resistance 50 mOhm/m.
The capacity of a cable rises with the size of the surface and with the reduction of the distance of the two leaders to each other.
With inductance is it exactly turned around, the further and the back leader remove lie apart, the more largely is inductance. The resistance depends on the resistivity of the used leader material (with silver smallest) and on the cross section (the more largely the smaller). The best leader silver, has better conductivity in relation to copper one approx. 15%. The derivative value and/or isolation value depends on the used dielectric. The insulator has a Ohm\'s resistance from some mega to Giga ohms.
Näherungsformeln: a=Abstand (center to center) in mm, D, D=kleiner, large diameter in mm
Twin lead without screen:
C [pF/m] = 12 * etar/log (2a/d)
L [µH/m] = 0.92*log (2a/d)
Coaxleitung:
C [pF/m] = 24,1 * etar/log (D/d)
L [µH/m] = 0.46*log (D/d)
Line resistance:
R [mOhm*m/mm ²] = Kupfer=17.8, silver =16.5 e.g. 3 m with 2,5 mm ² Kufer = 21.4 mOhm (with 20 degrees C)
Dielectric | Constant one (etar) | Dissipation factor (tangent delta)
PVC 5-8 0.1-0.15
PURELY 3-4 0.015-0.06
PE 2.3 0.0005
Ptfe 2 0.0002-0.0005
Silk 1.4 < 0.0005
Air 1 < 0.00001
The total characteristic of the cable:
This becomes by the structure: Arrangement of the leaders (coaxially, parallel, cross-interconnected, twisted, intertwined…), distance of the leaders to each other, with or without screen and the materials: Material (copper, silver, Goldlegierung), kind of the leader Lizte or massif, degree of purity and/or crystalline structure (normal, OFC, PCOCC, 6..8N copper, 4N or 5N pure silver), electrical resistance, insulating material (dielectric: PVC, PE, PP, teflon (ptfe), silicone, lacquers, fabrics), microphone IE sensitivity of the gesammten arrangement and skin effect with to large cable diameter (diameter <0.8mm, or flat line) determines.
The goal:
As balanced a relationship of the parameters as possible to each other (R/L=G/C) minimize the Widergabefehler. Unfortunately this is nearly impossible, since the parameters affect each other mutually and the source and the load must be also still considered. Experiences have shown that NF-small signal-cables (Interconect cables) as low a capacity as possible and as low an inductance as possible with at the same time low Ohm\'s resistance should exhibit loudspeaker cable (NF-Großsignalkabel).
A screen when NF-lines is not necessarily necessary with high level connections (CD - > amplifiers). For very small signals, like them with pick-ups the rule are (< 0.5mV), and with HF-transmission is however necessary they. With high frequency signals the screen must be very close and reciprocally attached. Hum troubles (magnetic fields) could be achieved only by ferrousmagnetic screen (ferrousmagnetic materials e.g. iron). Better a reasonable uncoupling is, i.e. far away from Trafos and mains and as short as possible and no loops moves.
With the coaxial cable the signal is carried via the interior leader and the screen, that cannot fulfill thus their function as screen to no more. The use of parallel-symmetrical cables with additional screen is better. The screen is then connected at the source side directly with mass and at the Empängerseite by a 10Ohm resistance. On one side do not as only as possible attach (bag screen), this can to HF-receipt lead!
Additionally with loudspeaker cables a low Ohm\'s resistance (high cross sections of the cable) affects the break-even factor (control of the amplifier of the loudspeakers). Low = high absorption = controlled, dry bass against gift!
Plant-caused sound differences:
Always also the output impedance of the transmitter (Za) and the feed impedance of the receiver (CPU) has a strong influence on the transmission circuit. The output resistance of equipment (RA) must be larger as low as possible and the input impedance and/or load resistance (RH) in the factor at least 100 (over match, break-even factor highly). Both should be as frequency-independent as possible.
A frequency independence with loudspeakers does not let itself avoid unfortunately, as constant a impedance process as possible however always is from advantage. Here one can hope only for a cleanly designed frequency switch!
With preamplifiers and sources of music the practicable value of the output resistance (RA) is with 10-100 ohms with final stages should not it 0,1 ohms not exceed (the lower so much the better!). The input impedance (RH) of receivers naturally lies between 10-50 kOhm (the smaller so much the better!). The inductance and capacity of the exit should be möglichtst small!
Unfortunately are not the values, as with the HF-technology usually, fixed in a standard. Some sources of program have an output resistance of 2000Ohm, the output resistance of a tube final stage can some ohms amount to, which means strong negative interactions with the cable!!
The output resistance (RA) of the source forms a low-pass filter together with the cable capacitance (Ck) and the entrance capacity (Cp) of the receiver. fG = 1 (6.28*Ra*Ck+Cp) example: Ra=2kOhm, Ck+Cp=2nF - > critical frequency fG ~ 40 kHz.
Often the source has an output ouple condenser and the receiver an entrance ouple condenser (AC coupling).
The two condensers (approx., Ce) are positioned by the Signalkabel connected in series. This causes that the resulting value changes. The new capacity is smaller: Cn = Ca*Ce/(Ca+Ce). This can shift possibly the lower critical frequency upward (less bass). The new lower critical frequency concerning the input impedance RH amounts to: fG = 1 (6.28*Re*Cn).
Many more badly however, that is the quality (quality, loss angle) of the resulting condenser suffers! (Series connection: Ca+Rk+Lk+Ce). This leads inevitably to losses of fine design and fine dynamics. Thus as always as possible connect DC-DC, DC-AC or AC-DC! During DC DC coupling must be naturally paid attention to DC voltage freedom!
The internal Koppelkondensatoren often are from cheap quality. Often at the exit from place and cost reasons a Elko (approx. 10-100 µF) is inserted, as well as at the entrance (approx. 0.1-4.7 µF) from cost reasons an inexpensive foil condenser (0.15-0.5€). A high-quality condenser costs tenfold!. Here each quantity sound potential is given away. Bad, strongly lossy condensers change the sound toward soft, less Deteilreichtum (with Elkos) or toward cold with oversubscribed and hard high clay/tone range (with simple foil condensers).
To neglect are not the internal equipment cable connections (e.g. in loudspeaker boxes). These can play a crucial role opposite the external wiring. Often these are together longer than the external wiring, besides of cheap quality, and thus sound killer!
Mass balance stream: The transmitter and receiver are on different mass potential flow in such a way a balancing current over the cable connection. This river mixes with the signal stream (modulation) and leads to sound changes. A cause is usually mains supply or HF-stray effect.
If at your plant cables with other characteristics sound better or worse,
so can be this because of a compensation of opposite characteristics.
With each error minimization a cable will bring klangliche advantages to the chain with neutral, highly detailed rendition however.
Digital transmission circuits:
Here the problems lie somewhat differently, there here square wave signals with constant amplitude (0,5 V with S/P-DIF, approx. 3-7 V with AES/EBU) and frequency (5,6 MHz with CD, 11,2 MHz with DVD) with fast flanks (approx. 5-30 LV) to be transferred must count here characteristics such as HF-range, low capacity, wave running time, good screen and characteristic impedance (root (L/C)).
The range should not be as high as possible around the square wave signal to affect. At HF (high frequency) must be worked with characteristic impedance adjustment. The source exit, the cable with the plugs and the source entrance must exhibit the same values (with digital audio 75 and/or 110 ohms). Deviations can lead to reflections and thus to intermodulation with the consequence of phase jitters. Silvered copper Koaxkabel, with substantial or as braid (StaCu) implemented interior leader and teflon isolation proved as very positive. On the screen under no circumstances (CE), there otherwise HF up to 250MHz (harmonic waves) may to do without to be radiated here be able. These are caught by other HIFI devices and by intermodulation develop rattle/clink!
The sound differences by digital cables are to be attributed probably mainly to different jitter characteristics. Which leads with a digital cable mainly to jitters (mismatching, is to small range, envelope delay distortions, Mikrofonie, memory effects by dielectric losses…), still weitestgehends unclearly. Ready-made solutions there are not unfortunately, there helps only heard also here. (- > further information)
Other sound influences:
In both worlds the plug connectors are not negligible! Characteristics such as contact transition resistance, boundary layers by material transitions (brass nickel gold), soldered connections, capacity and inductance, as well as ferrousmagnetic characteristics change likewise the sound.
With digital cables the Cinch plug not specified after characteristic impedance (<> 75 ohms) can contribute to which is also an falseadapted Koaxkabel (e.g. 50Ohm) of advantage. The BNC plug connector usual in the HF-measuring technique is more professional (- > see also digital exit).
Cables need to reach a bringing in time of approx. 30-45 minutes around their full efficiency.
(Information to the cause: Mikration, solvent core, grain boundaries, polar impurities, tribochemische influence,…)
Why cables from purest copper or pure silver?
Generally the effect is neglected that smallest (predominantly high frequency) rivers by cable impurities it lost go and/or are affected! This effect is similar to the neutral zones with semiconductors (assumption distortions with final stages).
This becomes understandable, if one regards the order of magnitude. With transmission dynamics of 90 railways the smallest rivers amount to with NF-cables approx. 100 well and with loudspeaker lines approx. 100 µA (0.0000001..0.0001 A).
These impurities are: Oxidation - > copper/silver crystal transitions, foreign atoms: Oxygen, free atoms in the Isolator-> of diffusion effects in the cable.
The molecules of leader materials have a crystal structure. The flowing through river must overcome the grain boundaries, which leads to losses. The same is valid for other impurities.
Due to its mechanical production line (crystalline structure) cables possess a direction of travel. Normally this is with an arrow away from the source marked. This is not the case, or from distrust, and/or curiosity can be determined this also by hearing tests.
Cables are in the smaller measure also Mikrofonieanfällig. In sound field the ladder are squeezed together, which changes the capacity.
The inhomogeneity of the current distribution rises with the cross section of the leader. A cause: The electrons urge under the self-magnetic field outward.
Static loading of the insulator can likewise lead to the sound influence.
Loudspeaker wiring:
Whether Biwiring (4-adrig) should or conventionally two-vein, at the rendition chain is tested. With Biwiring the frequency switch is divided into two branches (bass and high clay/tone), which are separately led up to the amplifier. So different specialized cable types can be used however with as same a sound characteristics as possible (identical Design) and the amplifiers see quasi over each cable a loudspeaker chassis with its switch. We made thereby best experiences.
The clear advantages from Biwiring are:
* The signal to the high clay/tone range is free from modulation effects (intermodulation) under the higher river of the bass range. I.e. the smaller and higher-frequency river of the Hochtöners cannot, as it is with a normal wiring the case from the bass signal, due to which common ground wire is modulated.
* With separately moved cables for deep and high clay/tone range also still the magnetic ouple effects (magnetic cross modulation) are void.
* Control amplifiers over the loudspeaker is better (absorption of the self induction and/or against EMK)
With Biamping per branch its own final stage is used. That is important the final stages is equivalent (same circuit design and thus resembles sound characteristics). The achievement for the branch of high clay/tone may be clearly smaller however.
Reason: The energy distribution decreases constantly with diaphragm deflection to high frequencies. From 100% of supplied achievement the distribution amounts to on the ranges: Low bass (20-70Hz), bass (70Hz-200Hz), central clay/tone (200Hz-3kHz), high clay/tone (3kHz - >20kHz) about 40/30/20/10%.
Notes:
* If the Biwiring possibility is not used, then the often usual metal bridges must be replaced by high-quality wire links, otherwise is to be counted on sound A BOSOMs.
* Better a good cable without Biwiring, than two inferior cables with Biwiring.
* It is to be usually realized better Biwiring with a cable (with at least 4 isolated veins) than doing without it.
to further information
Symmetrical or asymmetrical signal transmission?
During symmetrical transmission the signal in normal phase position becomes (+) and parallel to it a signal inverted (-) transmit. The mass serves only the screen. Everyone this from the studio technology coming XLR signal lines has two equal interior leaders and a screen. The goal can be attained a higher interference suppression, since this both interior leaders affect and waive themselves thus largest even. Further the danger is mass disturbances (loops) arises smaller.
A condition for it is however that the source exit and receiver entrance in each case doubles (symmetrically) to be present must. The quality of interference suppression depends on the “equality” of these circuits. I.E. the output and initially impedance (R + C), reinforcement, range, running time etc. of positive and negative branch same characteristics must, but accurately 180° opposite phase position to exhibit, what to high frequencies becomes ever more difficult.
Not symmetrical characteristics such as noise and rattle/clink and other sound-affecting parameters do not waive themselves unfortunately not, but increase. Besides the expenditure and thus the price are higher.
Inverting the exit is often reached by a concatenation. The inverted signal goes through thus two stages, while the non-inverting goes through only one stage. The quality (interference suppression) of the symmetrical entrance depends on its sum-and-difference amplifier qualities (common mode rejection factor, range) and can generally only with operation amplifiers be realised.
During often used pseudosymmetrical interconnecting of a symmetrical cable with Cinch plugs the screen is attached only on one side (bag screen), which become both identical interior leaders as signal leaders and mass used. This kind of the wiring became generally accepted in relation to the coaxial structure for NF (Koaxkabel are intended actually only for HF transmission).
Completely symmetric signal processing:
In the above mentioned case the equipment out and entrances (usually additional) are symmetriert, while the remainder of the circuit remains asymmetrically. During completely symmetric signal processing also the since transformation and reinforcement are laid out symmetrically. I.e. in the DAC and/or CD players, in the preamplifier and in the final stage (bridge connection) are developed in each case two branches per channel (inverts and not-inverts). This variant is to be found from cost reasons only very rarely.
In like far this expenditure in klanglicher improvement, is like always on a consistent (as error free ones as possible) conversion dependent and naturally also a question of cost settles.
Better a good asymmetrical exit as a pseudosymmetrical exit realised for advertising-effective reasons with cheap construction units.
"Wszystko powinno być zrobione maksymalnie prosto, ale nie prościej"-A. Einstein
