The equivalent series inductance (ESL) of resistors is miniscule and so is only apparent at super high frequencies (100s of GHz). Most resistors are soldered very close to the board surface so the inductance loop is very small anyway. Some resistors would have more ESL than others but it still doesn't matter in linear amps. I have been studying the problem of ESL in capacitors, which are much larger in value, and even then, the problem is only at high switching frequencies (of nonlinear topologies).
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I would think the inductance in the wiring and voice coils would be far greater than the inductance in a single resistor. If you wanted to be sure you could get some 8 ohm non-inductive power resistors at Radio Shack for $2.29 each and have your two 4 ohm pads for under $10.
Herman...Two of those in parallel (for 4 ohms) would have a 40 watt rating! I really was thinking in terms of a simple wirewound 4 ohm 10 watt costing 39 cents each. (Parts Express, but I don't want to pay shipping on this!)
I really was expecting someone to lecture me about why the resistor needs to be non-inductive.
North Creek Music makes non-inductive wire wound resistors that sound superb..The material that these great resistors are made of is their secret to their sound. Only thing I have heard that sound better are resistor bridges made from Vishay metal film type..They cost 6 bucks each and you need 10 in parallel to make one high power resistor..Resistors are the most over looked component part in a crossover..To bad ..they make more difference than a capacitor swap.The North Creeks are about 4 bucks each..Tom
Herman...Not really. Since "audiophile quality" non-inductive resistors are quite inexpensive (compared with inductors and capacitors) I have never given much thought to why non-inductive was important. The financial considerations of patching up a free set of junked speakers caused me to question the reason, so I thought I would ask the question and see if anyone can come up with an explanation. Isn't that what Audiogon is for?.
Theaudiotweak...As I said, I have always used "Audiophile" resistors (not necessarily North Creek items). But I don't know why, and I rather doubt that it would make any difference for these little boxes. When I replaced the crossovers of my Maggie MG1.6 I used $4 resistors, but that was only 2 percent of the project cost, and not worth much thought.
1. I asked because some people (like you) insist that resistor type affects sound. Although it doesn't make sense to me, I am open minded enough to listen to other points of view. So far I am unconvinced.
2. Please you tell me what constitutes an "Audiophile" resistor, apart from how it is described by the vendor, and the price.
I am not a material engineer. I am a good listener. I am opened minded..I will take chances. I have rebuilt many a speaker..Some of these speakers cost 10k a pair..The single biggest improvement were the replacement of the resistors...Most of these high-end speakers had quality caps and inductors but only five cent resistors..One designer with his name on the grill told me swapping resistors in a AC circuit like a speaker would make no difference..My ears and my eyes told me he was wrong. Swap out the resistors in your throw away speakers live a little learn alot..Please do this in a recordable and repeatable way..What you will experience and learn can be applied over and over again..The North Creeks are really good..Low noise may make the highs sound deficient at first..these babies take 100 hours to break-in..you will have greater definition, blacker backround, much more speed, resulting in better imaging...Tom
Hi Eldartford, I did experiment with resistors in the preamp's line section and they did made bigger difference to my ears than caps replacement. I replaced the old A&B carbon resistors with Holoco, Rodenstein ( they were at closeout price from welbornelabs) and Vishay. 20 cents vs the $2 A&B and I prefer the 20 cents resistors more.
Sorry El, I must have had you confused with another Eldartford who posted a troll looking to see who would respond to a question about the direction that wire was twisted, and a few other such inane questions.
My mistake, but once you have been pegged as one who is trolling bait, it is hard to shake that label.
Herman...I confess, that was me about the wire twisting. It was indeed an "inane" question, and intended as such, but only a slight extension of some ideas put forth here. (eg: wires on Dixie cups). Let's not take ourselves too seriously.
This question about non inductive resistors is for real. As Tom suggests (and because the cost is trivial) I will do a tradeoff between resistor types.
PS...I just saw the posting about the sound of Alnico magnets. That's as good or better than my wire twisting thing.
Resistors do make a big difference in the treble. This is most obvious on a speaker that uses a metal dome tweeter. A lot of the glare, hash, spit, and irritating sound is gotten rid of.
Just because a resistor costs $4 does not mean it will sound good. I have seen several expensive "audiophile" resistors that make things even worse.
There are not many real "audiophile" resistors. Like most things in this hobby, the upper echelon products aimed towards other industries do best in our applications. As someone who used to make the materials for the likes of Vishay, Sfernice, Holco, etc. I can tell you there are three main types of materials that go into good film thick/thin resistors:
1) 55% Palladium/45% Silver (Pd/Ag). Very low TCR (Temperature Coefficient of Resistance) and quite stable. Used in low resistance applications (0.1 Ohms to 10 or 100 Ohms - depending on the source material and company). Expensive, as both are precious metals. I believe these have the best sound.
2) Ruthenium. Less good in all respects than Pd/Ag, but provide higher resistance (>10 Ohms). Also expensive, as Ruthenium is also a precious metal, but much cheaper than Pd.
3) Carbon resistors. The most stable, and lowest cost. Can be good, but often can be poor sounding. It may depend on the source, but also the processing of the end user, as I have heard good and bad.
Personally, I prefer none of the above, and think a good wirewound resistor, such as Ohmite or NorthCreek, can sound the best, but there are just as many bad sounding ones, so many prefer film resistors.
Maybe that's why the Maggie MG1.6 sound good. Crossover consists of one inductor and one capacitor for the woofer, and one capacitor (implemented as a parallel group) for the tweeter. And NO RESISTOR unless you choose to insert one. This also made the cost to upgrade using top of the line components quite reasonable.
Of course Magnepanar designs and makes their drivers, (perhaps excepting the ribbon) and can play around with the driver designs to get the results they want. Most speaker system manufacturers have to make do with drivers that are designed and made by others, and then try to achieve the sound they want by complex crossover networks.
PS: Except for tweeter crossover (2000 Hz and up) I am a firm believer in low level electronic crossovers and biamplification.