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BENNIC CEMENT POWER RESISTORS SQF Series (Flat Sheet Type )1. Low inductance.2. Safety flameproof construction.3. Thin Light weight body save the PCB space considerably.4. Tolerance available ±10%, ±5% ±2% .
With our MResist SUPREME you can enjoy even finest details and spatial information which normally get lsot. Due to the complec bifilar structure from 1Ω with two wires being wound around the high-temperature-resistant cement element simultaneously the inductance is always below 0.075µH.In addition. the MResist SUPREME series features acoustic neutrality and music reproduction close to reality. This is due to a special manually applied fire-resistant casting compound which optimally fices and stabilises the resistor winding thus protecting it against microphony effects.In order to maintain high sound quality even at high load. we apply a special copper-nickel alloy as conducting material featuring a positive and extremely low temperature coefficient of only 50ppm/°C...
Capacitors show self-resonance, frequency-dependent dielectric loss and microphony; inductors have magnetic hysteresis, saturation and self-capacitance, among several defects. Any of these may become audible under certain conditions in a revealing audio system. One might therefore suppose that resistors at least are audibly perfect, or at least very close to it...
Reason? Maybe it has something to do with the harmonics, I speculate. xrk971 detected and measured what happened with a resistance from the new DIY class A ALPHA. He put a thin metal resistor and the harmonic profile changed to H3 predominant. It changed to a carbon and was H2 predominant again. Then changed to a thick metal and kept H2 predominant. Same values off course...
Characteristics: 1 % Tolerance Low noise figure Low inductance less than 0.7 uH Instant overload capacity Super heat dissipation, small linear temperature coefficient Low annual shift Flameprood and lightweight
“Our PTT6.5 woofer is the result of about 4 years of research. It has been a fruitful teamwork between Bruno, Carsten, Morten, and myself. This has resulted in a design that is vastly different from conventional drivers. In short, we have been on a crusade against all sources of intermodulation distortion. Psychoacoustics has correctly shown that our ears are not that sensitive to pure harmonic distortion – especially in the bass. However, our ears are way less forgiving when it comes to IMD when listening to complex music program material. Since it is impossible to only generate harmonic distortion without IMD, it has been necessary to reduce all nonlinear mechanisms in a speaker.The most known source of IMD is the position dependent force factor Bl(x) which we have made ruler flat over +-6mm excursion (+-10mm at -10% Bl). Less known is the current and frequency dependent modulation of the force factor (aka force factor modulation, flux modulation, reluctance force) which we have reduced by up to 40dB over comparable standard motors. Then we have the position dependent inductance which causes a modulation of the drive current, again reduced by a huge factor. A new (re)discovery is the gain modulation caused by the varying radiating area of conventional surrounds – this can cause an amplitude modulation of the midrange by +-10% easily. This has been reduced by orders of magnitude by our very special surround geometry. Finally, an extremely annoying distortion mechanism is the hysteretic memory of the iron in the motor. This distortion leads to a grainy non dynamic sound and lack of ‘black canvas’. We have managed to reduce this distortion by up to 50dB compared to industry benchmark drivers. Interestingly, the exact same hysteretic distortion can be found in class D amplifier output coils. Our 1ET400A amplifier embeds the coil in a control loop with over 70dB loop gain all the way to 20 kHz which effectively removes this distortion. We believe that the class D coil’s hysteretic distortion has been a large part of the bad reputation of early class D designs.”
Precision resistors built on VFR's unique Bulk Metal® Foil technology provide very low temperature coefficient of resistance (TCR) and exceptional long-term stability even in extreme temperatures. The devices provide a wide range of resistance values, with any resistance value within their given range available at any tolerance with no additional cost or lead time effect. On top of this specific “as required” values can be supplied at no extra cost or delivery...
You might try KOA Speer BPR series power resistors. They have essentially zero inductance as they are made from a cut plate of metal (no windiings of any sort or spiral cut metal thin film etc). I have measured a reduction of harmonic distortion vs even the venerable Panasonic ERX series resistors, which were my previous favorites.http://www.koaspeer.com/catimages/Products/BPR/BPR.pdfI have not seen anyone use these for XO's, but why not? They are 5W, so to get 10W, use half the value in series. They are not expensive either and take up little room on a PCB.I'll have to check out the Mills resistors. Maybe they would work well as amplifier MOSFET source or BJT emitter resistors as well.
Three curves showing resistor distortion. Using my bridge technique the fundamental of 0 level is suppressed.First a good Dale RN65 resistor, second an Ohmite 1/2 watt carbon composition type and finally the effect frequency has on another Dale.On the CC resistor it is not just the added harmonics, note the base spreading which can be caused by an increase in 1/f noise.On the third image notice how the third harmonic distortion increases as frequency decreases. Also not there is not much change in the second harmonic for a two octave change in frequency.
