I would approach this differently. There exists an infinite series of forward and backward waves for any mismatched line/load situation. The speaker Z is easy to evaluate at a given frequency. Then the series could be evaluated at any point in the system at say 10kHz, 20kHz, etc. to look for the phase delay. The solution could probably be stated with the characteristic impedance as the only free parameter so one could quantify directly the effect of match/mismatch. My bet is the delay manifested by phase vs frequency has little change with Zo over 8 to 150 Ohms at audio frequencies. That is the difference between the exact and lumped element answer.
Using the "perfect step" analysis approach, it is easy to see the difference between load z and settling time: If you use zip at 100 ohms, there will be no settling time whatsoever for a load of 100 ohms. Only prop delay, a few nanoseconds.
The time lag at the speaker will depend on the energy stored in the cable. The storage always trails the stimulus.
Since we are capable of localization discernment in the 500 to 12Khz range at a level from 1.5 uSec to roughly 50... Any testing we do must be able to see that.
To measure a 10 uSec delay in a 500 hz sine into an 8 ohm resistive load at current, that is not an easy thing to do accurately. The inductive reactance of a normal current viewing resistor swamps that. I'm forced to design my own resistor. I'd like to go down to 10 milliohms if possible, and self inductance loop pickup down in the 10 picohenry or so range. I've got the 1/8th copper, resistors on order, but I think I'm going to need several drill bits to get all the holes (I'll need several hundred). I've used 20 and 24 thousanths bits before in copper, it's never fun..
In between the honeydews of course..😉
The low value resistor of course, is needed once I want to measure a resistive/inductive/capacitive load simulating an actual speaker..while measuring a pure resistive load gives data, the end target is of course, audio stuff..
Cheers, John
The time lag at the speaker will depend on the energy stored in the cable. The storage always trails the stimulus.
Since we are capable of localization discernment in the 500 to 12Khz range at a level from 1.5 uSec to roughly 50... Any testing we do must be able to see that.
To measure a 10 uSec delay in a 500 hz sine into an 8 ohm resistive load at current, that is not an easy thing to do accurately. The inductive reactance of a normal current viewing resistor swamps that. I'm forced to design my own resistor. I'd like to go down to 10 milliohms if possible, and self inductance loop pickup down in the 10 picohenry or so range. I've got the 1/8th copper, resistors on order, but I think I'm going to need several drill bits to get all the holes (I'll need several hundred). I've used 20 and 24 thousanths bits before in copper, it's never fun..
In between the honeydews of course..😉
The low value resistor of course, is needed once I want to measure a resistive/inductive/capacitive load simulating an actual speaker..while measuring a pure resistive load gives data, the end target is of course, audio stuff..
Cheers, John
None at all. I actually have brass sheet from the antique clock repair work..
But I don't think it needs plating, I can solder to the base brass easily enough.
Nice idea..thanks
Cheers, John
But I don't think it needs plating, I can solder to the base brass easily enough.
Nice idea..thanks
Cheers, John
Are you talking about an ear to ear delay of 1.5 usec? Or a distance of about 1.5/1000 of a foot?
O.K. John,
You don't need to silver plate it other than it looks more high tech. I expect you will at least drill a nice pattern of larger holes to make it look like there is more magic involved than there really is!
When I get around to it I might lay out a set of PC cards to do the same thing. Of course I also might just punch it out with my CNC turret press.
The smallest punch I have is .082", then I would have to write G code for the part. G20, G74, G64, G5, G3 should make a plate with a matrix of holes. If I got fancy I'd add another G74 and get alternating large and small holes so the 1/2 of the resistor bodies could pass through one plate and no insulators required.
ES
Ear to ear.
If I drill larger holes, the electrons will either spill out, or they will aquire a spin as they avoid the hole...dizzy electrons are not well behaved charges.
That's what I used for the first few. The problem is dissipation. If I sand the sides flat to bond it to a heat sink, there will be no solder joint left with the pc stuff.
Using .125 thick copper gives some contact area after I've sanded it nice and flat. Otherwise, you are relying on free air, it'll get warm on me..one of the physicists here toasted the one I made for him..
I have the plates all as close to the bodies as physically possible. The issue is lead length affecting inductance and overall power dissipation.
Ya know, I could easily use clad PC for the top two plates, and stick to the brass for the heatsink contact.
Cheers, John
I got lured into buying a pair of Chord Chorus Interconnects between my Arcam CD36 and the F4. YES, they did sound superior to Wallmart specials but I'm hard pressed to declare any difference between them at $400 and a good pair of Van-de-Haals at $80.
IMHO with good quality plugs at both ends and reasonable cabling, you wont go far wrong. RG58 Satellite Installation cable makes pretty good cable at audio frequencies.
IMHO with good quality plugs at both ends and reasonable cabling, you wont go far wrong. RG58 Satellite Installation cable makes pretty good cable at audio frequencies.
No, I havent told it in this thread. Meashurements would be wery interesting if just someone could come up with what or how to meashure exactly what we`re after.
If you can`t (more or less) trust your ears then you`re either a newbie or you simlpy haven`t got what it takes to be good in this game. Eitherway, most people realises that my simple diy twin-coax made from Vivanco KX-710 are stunningly clean and makes their system sound airy & clean, even if they don`t have the same amount of experience as me. The inner core of this coax is a treashure.
The null technique, the voltage at the load nulled against an inverted version of the excitation, would give about 16mV per volt of excitation at 1.8 degrees of phase (10usec at 500Hz). The phase of the null signal as you go through null is a pretty good indicator of exact null. So at 10V AC the best null you could get in this case would be 160mV AC . This is of course only for the resistive case where V and I have to be in phase.
The big question is, would the voltage across a current viewing resistor be in phase with the current flowing through it?
If you simply put the probes on either end of the resistor, you pick up the time varying field generated by the resistor. For low value CVR's, that is very a very significant error in the phase measurement.
I had this problem with a 250 micro-ohm resistor a while ago...by altering the pickup wire geometry, I eliminated it.
My CVR by default, will have none. (to speak of)
Cheers, John
Ok, folks. 96 pages is a helluva lot to go through so I'll take my chances and hope nobody has been writing about UBYTE-2 speaker cable by Thorsten Loesch in this thread. I've got my self a piece of AIRCOM PLUS which should, at least according to Thorsten, be perfect for the purpose. Now, I've couple of questions that I'd like to get answered before I go hands on with that little project of mine.
First, I'd like to have it confirmed by some independent source, like you guys here 😉, that a cable set up like this really works as prescribed. Thorsten Loesch is well renown within HiFi community, especially in the UK but it never harms to get a second opinion.
Second, how much of the UBYTE-2's properties would be lost if I skipped cross coupling the coax cables and just run them "plain" as seen on the image below? Ie just connecting the shield to the inner conductor.
First, I'd like to have it confirmed by some independent source, like you guys here 😉, that a cable set up like this really works as prescribed. Thorsten Loesch is well renown within HiFi community, especially in the UK but it never harms to get a second opinion.
Second, how much of the UBYTE-2's properties would be lost if I skipped cross coupling the coax cables and just run them "plain" as seen on the image below? Ie just connecting the shield to the inner conductor.
Attachments
Find a wizard to ask? Well I figure I just could settle for jneutron or any other bloke on this forum to answer my questions. It's sure good enough for me 😛 😉
You mean, even if I make things up??😀
Seriously...
I believe by cross connected you mean each amp and speaker terminal is split between one shield and the other's center?
That configuration reduces the overall cable inductance by reduction of external field. It's just another tradeoff between L and C. Remember, for cables, the LC product is fairly represented as a constant...it is exactly represented as a constant only for pure coax and wide stripline constructions.
To actually calculate the inductance, you need to know the resistance of the core and shield. Then, one can calculate the system inductance as a sum of the coaxial inductances plus the external parallel wire inductance. Note that if the core and shield have identical resistances, there will be full cancellation of the parallel wire field, leaving only the two coaxes in parallel operation.
Your re-drawn configuration will not cancel any inductance at all, and the inductance of the cable will be easily calculated using the terman equation, that is the same as a zip wire. It would be exactly like a pair of conductors of equivalent guage.
For either case, I'd still recommend twisting the two together to keep the inter-conductor spacing as low as possible.
As for audibility, I've seen no test data to indicate differences which were discernable in controlled listening..so I cannot say what the functionality will be..just the science man....nuttin but the science..
Cheers, John
96 pages might be a lot, but at least you could check out the heading, it says "..lies about interconnects", not speakercables.
All conductors will "conduct" more or less, but a tiny coax (like all other tiny conductors) will kill the dampingfactor or the amps ability to breath, like a restrictor on a racecars carburator kills power.
No part of any signal should ever run through shields like this, only single massive conductors if you want it to stay clean.
nuttin but the science you say...
Well as far as you making things up is concerned as long as you don't come up with something that'll short my amp it's all nice 'n dandy to me 😉
By cross connected I mean exactly what you wrote, each amp and speaker terminal is split between one shield and the other's center as seen on UBYTE-2 page I linked to.
What I really want to know is whether I need to go the lengths Thorsten's proposing or if I can get away doing it "my way" as seen on the image I attached in order to get an equal end result ie providing myself with a reasonably good speaker cable. I'm aware that my configuration doesn't make any contribution when it comes to reducing inductance or capacitance or resistance for that matter it's just that it's so much easier to carry out practically. No need for soldering or crimping or anything of that kind. But if you think that my configuration will worsen the cables properties when compared to UBYTE-2 then I'm ready to make sacryfice of getting my fingers burned by solder iron.
Then yout recommendation of twisting the two together to keep the inter-conductor spacing as low as possible. I'm not sure I can do that considering the thickness of the coax cables involved (10,3 mm). Maybe keeping the two in parallel packed closely together or slightly twisted will do the trick?
Cheers!
Well as far as you making things up is concerned as long as you don't come up with something that'll short my amp it's all nice 'n dandy to me 😉
By cross connected I mean exactly what you wrote, each amp and speaker terminal is split between one shield and the other's center as seen on UBYTE-2 page I linked to.
What I really want to know is whether I need to go the lengths Thorsten's proposing or if I can get away doing it "my way" as seen on the image I attached in order to get an equal end result ie providing myself with a reasonably good speaker cable. I'm aware that my configuration doesn't make any contribution when it comes to reducing inductance or capacitance or resistance for that matter it's just that it's so much easier to carry out practically. No need for soldering or crimping or anything of that kind. But if you think that my configuration will worsen the cables properties when compared to UBYTE-2 then I'm ready to make sacryfice of getting my fingers burned by solder iron.
Then yout recommendation of twisting the two together to keep the inter-conductor spacing as low as possible. I'm not sure I can do that considering the thickness of the coax cables involved (10,3 mm). Maybe keeping the two in parallel packed closely together or slightly twisted will do the trick?
Cheers!
Well my bad there... If me posting in this thread about this particular matter is a such breach of rules then I applogize and hope that mods move my posts to whichever department they belong to. I googled and ended up on page 2 and didn't really pay attention to the heading since I got all excited about finally finding a place where people talked about the very same problems that made me bang my head to the wall.
Speaking of people not reading what's written, I can't for the love of god understand how you can call the Aircom Plus a tiny coax.
Cheers!
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