mikepowellaudio88 posts11-18-2019 12:55amAtDavid and Dimora , Mi Casa es Su Casa for anything HiFi related. Its no trick of marketing , Im not smart enough for that. I’m sick of hearing this back and forth perpetual argument. I want to abolish it. I just offered anyone lets do this .. did you see how much interest there was in stopping the argument and getting to the bottom of it. ? Clearly nobody will come from overseas, that never crossed my mind. So you 2 are perfect, you guys dont know me and I will state for the record I dont think I know either of you, but based on moniker I dont know you guys.. So do either of you two have any $1000 plus power cords ? if so , we’ve got a shootout. If not, then you two are Audiogon forum users that can represent the AG Group for this thread. Keep in mind, I am a straight shooter. if something sounds better than my cable I will acknowledge it, furthermore if we become friends while you are here you must maintain an honest opinion even if you think Im a great guy and the other cable sounds better. Now if there is no $1K plus cable you can bring, then I need to know if you each are power cord believers or not, if you are , then come over any ways and we can listen to 3D Holographic imaging. Its a good reference point from which to judge other rigs, and its always fun for me to experience it in other peoples rigs because it is elusive. If you dont know what you think or better yet are a non believer that is OK with being converted to believer (if its truly heard) then come on over and Ill prove power cords work an a big way. There are some folks not willing to be converted , and that bias makes a closed mind, so its futile at that point. Every Friday is HiFi Fridays around here. I am in Smyrna by the new Battery Park if you google my username or just go to my username.com youll find my phone number to call and chat.. ame.com youll find my phone number to call and chat..
atdavid432 posts11-18-2019 11:23amI am there for work every 8 weeks approximately, but no guarantees on a Friday. I am certainly in. I don’t think it matters if me or Dimora is a believer or not, as long as you are. If you can pick your cables out blind (or between a basic shielded cable and yours) then you have proved they make a difference. I have a strong suspicion this exercise will go nowhere. No such meeting will ever happen. Prove me wrong. |
atdavid432 posts11-20-2019 10:10am"Originally patented by Polk 30ish years ago."
Matt Polk did indeed patent the use of Zobel networks in loudspeakers. That was in response to power amps self-destructing when using Polk's high-capacitance Cobra speaker cables. The concept of Zobel networks, however, was developed by Otto Zobel of Bell Labs in 1923. |
twoleftears1,947 posts11-20-2019 10:36am"Any way you slice it, Noel Lee has a lot to answer for."
What exactly should Noel Lee answer for? |
It is not a Zobel network, though it looks the same, it performs a much different function. A Zobel network is placed, typically across the woofer, so that as the impedance of the woofer goes up, the Zobel network simulates a constant impedance. That constant impedance allows the crossover to work properly. These were used in speakers well before Polk. Polk patented putting an RC-damper/snubber across the speaker terminals. The purpose of this was to dampen high frequency oscillations. turnbowm50 posts11-20-2019 2:14pm
atdavid432 posts11-20-2019 10:10am"Originally patented by Polk 30ish years ago."
Matt Polk did indeed patent the use of Zobel networks in loudspeakers. That was in response to power amps self-destructing when using Polk’s high-capacitance Cobra speaker cables.
The concept of Zobel networks, however, was developed by Otto Zobel of Bell Labs in 1923. |
atdavid, How is the series R-C network (Zobel) that is used to provide a constant impedance different from the series R-C circuit used by Polk to dampen power amp oscillations? To me, they serve a dual purpose. I thought you might find this excerpt from Nelson Pass's discussion of speaker cables to be of interest. ... "After a period of confusion, Matt Polk and I realized independently tahat the lack of a characteristic termination was causing the problem. Polk developed and patented a "damper" consisting of a .047uF capacitor and 6 ohm resistor in series placed across the loudspeaker, while I used the same network but with .1uF and 5 ohms. The results of this network are seen in Fig. 8 where the resonance in the pulsed waveform is damped out, restoring stability to an otherwise oscillating amplifier. Since Polk's commercial introduction of the damper circuit we have found it cures oscillation problems caused by the other exotic low inductance cables. It is necessary whenever a reasonably long length (>3 feet) of low inductance cable is mated with any wide bandwidth amplifier. It interacts unfavorably with twin lead conductors (Fig. 8) which require higher impedance values (say, .01uF, 60(2); however, twin lead's higher characteristic impedance and resonant frequencies are in any case unlikely to induce oscillation in amplifiers now available." https://www.passlabs.com/press/speaker-cables-science-or-snake-oil
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