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#1
Posted to rec.audio.tubes
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Professional Radio Engineer
Who is that "professional radio engineer", living not far from Canberra and
selling dodgy tube amps? http://www.ebay.com.au/itm/110991918... 4.m1423.l2649 Patrick would know... Spray painting the whoile transformer is a dodgy job. Laminates should be painted black, while the covers -- different colour or crome. And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! Regards, Alex |
#2
Posted to rec.audio.tubes
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Professional Radio Engineer
"Alex Pogossov" And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! ** You must be thinking of "audiophools" not audiophiles. Nickel plated *brass* 1/4 inch jacks and plugs are fine for speakers, millions of instrument amps have used them for decades. Removal and insertion plus occasional cleaning is all that is needed. Gold plating is only for small signals. .... Phil |
#3
Posted to rec.audio.tubes
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Professional Radio Engineer
"Phil Allison" wrote in message ... "Alex Pogossov" And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! ** You must be thinking of "audiophools" not audiophiles. Nickel plated *brass* 1/4 inch jacks and plugs are fine for speakers, millions of instrument amps have used them for decades. Removal and insertion plus occasional cleaning is all that is needed. Gold plating is only for small signals. Ah, was kidding... For the instrument amps, perhaps a jack is OK, but audiophools shall use enormous gold plated terminals, and a special litz speaker wire of perhaps 2000 insulated 0.07mm strands each, so that ohmic loss is small and constant from DC to 1MHz..Otherwise you lose transparency of the highs! |
#4
Posted to rec.audio.tubes
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Professional Radio Engineer
On Fri, 21 Dec 2012 16:20:27 +1100, "Alex Pogossov"
wrote: "Phil Allison" wrote in message ... "Alex Pogossov" And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! ** You must be thinking of "audiophools" not audiophiles. Nickel plated *brass* 1/4 inch jacks and plugs are fine for speakers, millions of instrument amps have used them for decades. Removal and insertion plus occasional cleaning is all that is needed. Gold plating is only for small signals. Ah, was kidding... For the instrument amps, perhaps a jack is OK, but audiophools shall use enormous gold plated terminals, and a special litz speaker wire of perhaps 2000 insulated 0.07mm strands each, so that ohmic loss is small and constant from DC to 1MHz..Otherwise you lose transparency of the highs! I saw one site selling multi-thousand dollar speaker cables with the 'feature' that in THEIRS the signal traveled at 90% the speed of light. Which, of course, is critical when sending audio 10 feet. |
#5
Posted to rec.audio.tubes
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Professional Radio Engineer
"flipper" wrote in message ... On Fri, 21 Dec 2012 16:20:27 +1100, "Alex Pogossov" wrote: "Phil Allison" wrote in message ... "Alex Pogossov" And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! ** You must be thinking of "audiophools" not audiophiles. Nickel plated *brass* 1/4 inch jacks and plugs are fine for speakers, millions of instrument amps have used them for decades. Removal and insertion plus occasional cleaning is all that is needed. Gold plating is only for small signals. Ah, was kidding... For the instrument amps, perhaps a jack is OK, but audiophools shall use enormous gold plated terminals, and a special litz speaker wire of perhaps 2000 insulated 0.07mm strands each, so that ohmic loss is small and constant from DC to 1MHz..Otherwise you lose transparency of the highs! I saw one site selling multi-thousand dollar speaker cables with the 'feature' that in THEIRS the signal traveled at 90% the speed of light. Which, of course, is critical when sending audio 10 feet. A brilliant idea came to me. We need to start manufacturing special audiophoolish coaxial cables with Z=4ohm impedance, Z=8ohm impedance and Z=16ohm impedance. Using such coax as a speaker cable an audiophool can achieve perfect matching of the speakers to the amp in the widest frequency range. Group delay will be constant within picoseconds! They will line up to buy such a cable. It will be very thick though as the inner diameter shall be very close to the outer diameter to have low characteristic impedance. Those audiophools who use Cyclotron amps, of course can not use unbalanced coax in a fully balanced system. For those we will manufacture multilayer ribbon cables with the same standard impedances! (Ordinary twisted pair is unsuitable -- it has far too high characteristic impedance.) Perhaps as an alternative a special twisted Litz can be used with half of the strands in parall serving as conductor A, the other half -- conductor B. Most likely it shall be impregnated by some high epsilon goop -- for higher capacitance and hence lower impedance. How does this sound? |
#6
Posted to rec.audio.tubes
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Professional Radio Engineer
"Alex Pogossov" A brilliant idea came to me. We need to start manufacturing special audiophoolish coaxial cables with Z=4ohm impedance, Z=8ohm impedance and Z=16ohm impedance. ** Been around since the 1970s. Using such coax as a speaker cable an audiophool can achieve perfect matching of the speakers to the amp in the widest frequency range. ** Shame how loudspeakers do not have simple impedances over the audio band, let alone beyond it. While it is possible to add passive networks in parallel with a speaker ( ie zobels) to fix this, nobody ever wants to. Exceptions: Some Magneplaner models and the KEF 104AB were close to resistive over the audio band. ..... Phil |
#7
Posted to rec.audio.tubes
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Professional Radio Engineer
On Sun, 23 Dec 2012 12:03:45 +1100, "Alex Pogossov"
wrote: "flipper" wrote in message .. . On Fri, 21 Dec 2012 16:20:27 +1100, "Alex Pogossov" wrote: "Phil Allison" wrote in message ... "Alex Pogossov" And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! ** You must be thinking of "audiophools" not audiophiles. Nickel plated *brass* 1/4 inch jacks and plugs are fine for speakers, millions of instrument amps have used them for decades. Removal and insertion plus occasional cleaning is all that is needed. Gold plating is only for small signals. Ah, was kidding... For the instrument amps, perhaps a jack is OK, but audiophools shall use enormous gold plated terminals, and a special litz speaker wire of perhaps 2000 insulated 0.07mm strands each, so that ohmic loss is small and constant from DC to 1MHz..Otherwise you lose transparency of the highs! I saw one site selling multi-thousand dollar speaker cables with the 'feature' that in THEIRS the signal traveled at 90% the speed of light. Which, of course, is critical when sending audio 10 feet. A brilliant idea came to me. We need to start manufacturing special audiophoolish coaxial cables with Z=4ohm impedance, Z=8ohm impedance and Z=16ohm impedance. Using such coax as a speaker cable an audiophool can achieve perfect matching of the speakers to the amp in the widest frequency range. Group delay will be constant within picoseconds! They will line up to buy such a cable. It will be very thick though as the inner diameter shall be very close to the outer diameter to have low characteristic impedance. Those audiophools who use Cyclotron amps, of course can not use unbalanced coax in a fully balanced system. For those we will manufacture multilayer ribbon cables with the same standard impedances! (Ordinary twisted pair is unsuitable -- it has far too high characteristic impedance.) Perhaps as an alternative a special twisted Litz can be used with half of the strands in parall serving as conductor A, the other half -- conductor B. Most likely it shall be impregnated by some high epsilon goop -- for higher capacitance and hence lower impedance. How does this sound? Well, I suppose we just wouldn't mention that to be a transmission line at audio frequencies the cable would have to be miles long. |
#8
Posted to rec.audio.tubes
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Professional Radio Engineer
"flipper" Well, I suppose we just wouldn't mention that to be a transmission line at audio frequencies the cable would have to be miles long. ** Not this stupid red herring again !!! I though only ****wit radio hams misunderstood the topic of transmission lines so badly. The theory of "electrically short" transmission lines says they act like pure capacitors if unterminated and like inductors if shorted. As with longer transmission lines, when terminated by a resistance equal to the line's characteristic impedance - there is almost no upper limit to the frequency range. Ordinary twin speaker cables are transmission lines, but with a characteristic impedance of around 100 ohms - so when terminated by an 8 or 4 ohm resistor show high frequency roll off above the audio band due to series inductance. Specially made cables ( woven conductor or strip lines) with a characteristic impedance of 8 ohms show no such roll of. Mostly this roll off hardly matters, but a few cases exist where the speaker's impedance falls to a low value ( 1 or 2 ohms) at or near the top of the audio band and then it can matter quite a bit. The original QUAD ESL is one example and even the AR11 has a huge dip in the impedance at 5 to 6 kHz ..... Phil |
#9
Posted to rec.audio.tubes
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Professional Radio Engineer
On Sun, 23 Dec 2012 14:59:30 +1100, "Phil Allison"
wrote: "flipper" Well, I suppose we just wouldn't mention that to be a transmission line at audio frequencies the cable would have to be miles long. ** Not this stupid red herring again !!! I though only ****wit radio hams misunderstood the topic of transmission lines so badly. The theory of "electrically short" transmission lines says they act like pure capacitors if unterminated and like inductors if shorted. I know about "electrically short" transmission lines but sending audio over a few meters of cable is not just "electrically short," it's ridiculously short and renders any notion of 'characteristic impedance' irrelevant. At audio frequencies the conditions for it to have meaning simply don't exist any more than it matters if your audio gets to the speaker at .6 or .9 the speed of light. As with longer transmission lines, when terminated by a resistance equal to the line's characteristic impedance - there is almost no upper limit to the frequency range. You should try measuring that 'almost no upper limit' sometime. You'll be sorely disappointed but we weren't talking about 'any frequency' anyway. The purpose is to send audio and not 1 MHz, or some other 'almost no upper limit' red herring. Move the frequency up high enough and "electrically short" begins to have some meaning, but not at audio over a few meters. Ordinary twin speaker cables are transmission lines, but with a characteristic impedance of around 100 ohms - so when terminated by an 8 or 4 ohm resistor show high frequency roll off above the audio band due to series inductance. Specially made cables ( woven conductor or strip lines) with a characteristic impedance of 8 ohms show no such roll of. I don't care what the "above the audio band" roll off is and have no idea why a speaker would either. Mostly this roll off hardly matters, but a few cases exist where the speaker's impedance falls to a low value ( 1 or 2 ohms) at or near the top of the audio band Which rules out any notion of supposedly 'impedance matching' the alleged mythical 'transmission line'. and then it can matter quite a bit. The original QUAD ESL is one example and even the AR11 has a huge dip in the impedance at 5 to 6 kHz The unfortunate speaker cable finds itself stuck between the amplifier, a low-output impedance voltage source, and the loudspeaker, whose impedance and phase are all over the place. As such, the actual impedance with which the speaker cable works is effectively zero, because it is electrically short in the ridiculously extreme and connected across an amplifier having negligible output impedance. As a result, a loudspeaker cable is categorically not a 'transmission line'. .... Phil |
#10
Posted to rec.audio.tubes
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Professional Radio Engineer
"flipper = ****WIT PIG " , "Phil Allison" "flipper" Well, I suppose we just wouldn't mention that to be a transmission line at audio frequencies the cable would have to be miles long. ** Not this stupid red herring again !!! I though only ****wit radio hams misunderstood the topic of transmission lines so badly. The theory of "electrically short" transmission lines says they act like pure capacitors if unterminated and like inductors if shorted. I know about "electrically short" transmission lines but sending audio over a few meters of cable is not just "electrically short," it's ridiculously short and renders any notion of 'characteristic impedance' irrelevant. ** But I just proved that stupid idea wrong - YOU IGNORANT **** HEAD !!!! As with longer transmission lines, when terminated by a resistance equal to the line's characteristic impedance - there is almost no upper limit to the frequency range. ( snip putrid, ****wit **** ) Ordinary twin speaker cables are transmission lines, but with a characteristic impedance of around 100 ohms - so when terminated by an 8 or 4 ohm resistor show high frequency roll off above the audio band due to series inductance. Specially made cables ( woven conductor or strip lines) with a characteristic impedance of 8 ohms show no such roll of. ( snip more ****wit **** ) Mostly this roll off hardly matters, but a few cases exist where the speaker's impedance falls to a low value ( 1 or 2 ohms) at or near the top of the audio band Which rules out any notion of supposedly 'impedance matching' ... ** Your ****wit idea pal, not mine - ASSHOLE !!! and then it can matter quite a bit. The original QUAD ESL is one example and even the AR11 has a huge dip in the impedance at 5 to 6 kHz The unfortunate speaker cable finds itself stuck between the amplifier, a low-output impedance voltage source, and the loudspeaker, whose impedance and phase are all over the place. As such, the actual impedance with which the speaker cable works is effectively zero, ** WRONG !!! It has series inductance, quite a bit if it is more than 5 metres long. because it is electrically short .... ** Go choke to death of your Xmas turkey - you vile pile of worthless scum. |
#11
Posted to rec.audio.tubes
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Professional Radio Engineer
On Sun, 23 Dec 2012 19:08:11 +1100, "Phil Allison"
wrote: "flipper = ****WIT PIG " , "Phil Allison" "flipper" Well, I suppose we just wouldn't mention that to be a transmission line at audio frequencies the cable would have to be miles long. ** Not this stupid red herring again !!! I though only ****wit radio hams misunderstood the topic of transmission lines so badly. The theory of "electrically short" transmission lines says they act like pure capacitors if unterminated and like inductors if shorted. I know about "electrically short" transmission lines but sending audio over a few meters of cable is not just "electrically short," it's ridiculously short and renders any notion of 'characteristic impedance' irrelevant. ** But I just proved that stupid idea wrong - YOU IGNORANT **** HEAD !!!! Nope. As with longer transmission lines, when terminated by a resistance equal to the line's characteristic impedance - there is almost no upper limit to the frequency range. ( snip putrid, ****wit **** ) Ordinary twin speaker cables are transmission lines, but with a characteristic impedance of around 100 ohms - so when terminated by an 8 or 4 ohm resistor show high frequency roll off above the audio band due to series inductance. Specially made cables ( woven conductor or strip lines) with a characteristic impedance of 8 ohms show no such roll of. ( snip more ****wit **** ) Mostly this roll off hardly matters, but a few cases exist where the speaker's impedance falls to a low value ( 1 or 2 ohms) at or near the top of the audio band Which rules out any notion of supposedly 'impedance matching' ... ** Your ****wit idea pal, not mine - ASSHOLE !!! If you don't know what the topic was then why are you babbling about it? Alex explicitly said "... Z=4ohm impedance, Z=8ohm impedance and Z=16ohm impedance. Using such coax as a speaker cable an audiophool can achieve perfect matching of the speakers to the amp..." His use of "audiophool" should have been clue enough he was making a 'joke'. and then it can matter quite a bit. The original QUAD ESL is one example and even the AR11 has a huge dip in the impedance at 5 to 6 kHz The unfortunate speaker cable finds itself stuck between the amplifier, a low-output impedance voltage source, and the loudspeaker, whose impedance and phase are all over the place. As such, the actual impedance with which the speaker cable works is effectively zero, ** WRONG !!! It has series inductance, quite a bit if it is more than 5 metres long. Yes, it does have a small inductance and that you are 'concerned' with it proves you do NOT have a 'transmission line' because in a properly matched 'transmission line' the L and C 'vanish'. because it is electrically short .... ** Go choke to death of your Xmas turkey - you vile pile of worthless scum. One can always tell when Phil 'loses' because he reverts to a 3 year old, snipping everything you wrote, and his mind collapses into a puddle of Tourette babble. |
#12
Posted to rec.audio.tubes
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Professional Radio Engineer
On Friday, 21 December 2012 13:07:28 UTC+11, Alex Pogossov wrote:
Who is that "professional radio engineer", living not far from Canberra and selling dodgy tube amps? http://www.ebay.com.au/itm/110991918... 4.m1423.l2649 Patrick would know... Spray painting the whoile transformer is a dodgy job. Laminates should be painted black, while the covers -- different colour or crome. And besides, "professionals" do not use 6.3mm jacks for the speaker connectors, unless the contacts are gold plated. With nickel plated steel, contact resistance is unstable within a few milliohms which is no-no for any decent audiophil! Regards, Alex Why on earth would I know a so called "professional radio engineer" not far from Canberra? The Ebay amateur guy you refer to is selling a POS ancient Mullard amp that has been painted grey all over, and he is located in a small country town called Bungendore, about 35km away from where I am in central Canberra cbd, and on road between here and Batemans Bay on sth Coast. The population of Canberra plus 50km radius is about 380,000 ppl, and i guess there are many ppl with Old Krappe amps who I don't know, and many of them don't know me, or know about me, or wouldn't want to ever know me if they ever did get to know my unbending opinions about Olde Junke that they have dressed up to sell by painting grey, while perhaps describing themselves as professionals while not being able to support that claim, or show any sign of any professionalism, or tradesmen like worthiness or honesty in any way. While the seller fails to show he is reputable, he doesn NOT show he is disreputable, and he only wants a low price which I am sure he will get, maybe $100 even, and even if it doesn't work, maybe another $100 worth of second hand parts and some labour might fix it. The mono amp being sold seems to be just ONE, not a matching pair, and seems to have an old Leak OPT at one end of the chassis. Other parts on chassis look very generic old stuff, and R&C underchassis are combination of cheap 1W carbon film garbage quality R, with variety of some newish C plus mostly very old C parts from 1960s. So, underchassis has Real Crap that has not been re-engineered properly. 6mm jack at back is fine if in good condition, for low power, and the amp should suit somebody who wanted a low power mono system. There is room to put in a source switch and volume control to allow use of modern sources like CD, AM-FM tuner etc, or else the amp could be used for a low power musician's amp. |
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