OF COURSE, MuMetal can do what is designed to do, and sometimes it is necessary, such as around tape reproduce heads, etc. However, it can distort, because it EASILY saturates and then can add distortion to the signal nearby. Is it a lot of distortion? No, but it is measurable. It is the same with soft iron, but less so.
Everyone, learn and grow, or do something else for fun and profit. Why challenge what we have learned over the decades? Do you really think that we have gone off track? IF you do, then make something so good that we all listen up and notice. That is the way to a good reputation in audio design, AND don't you or your family members decide if it is good, you (and I) are too biased, instead get third parties with audio experience to listen to your setup and efforts. Hopefully they will give you honest feedback, and you can learn from their evaluation, like a book editor may help a author.
To think that I and my fellow experienced designers ( or we) don't don't know about steel construction, or its properties, is a joke! We have used it for decades, and only reluctantly dropped it for more expensive aluminum construction.
Everyone, learn and grow, or do something else for fun and profit. Why challenge what we have learned over the decades? Do you really think that we have gone off track? IF you do, then make something so good that we all listen up and notice. That is the way to a good reputation in audio design, AND don't you or your family members decide if it is good, you (and I) are too biased, instead get third parties with audio experience to listen to your setup and efforts. Hopefully they will give you honest feedback, and you can learn from their evaluation, like a book editor may help a author.
To think that I and my fellow experienced designers ( or we) don't don't know about steel construction, or its properties, is a joke! We have used it for decades, and only reluctantly dropped it for more expensive aluminum construction.
A good example of shielding can be seen with the old marantz CD players, the 63MK2 and 63MK2 KI signature. In the MK2 shielding on the HDAM was done with steel but the signature model pure copper was used. I cant remember now for sure but I think the inside case was also copper or copper plated on the signature. Anyway at that time I read up on the internet exactly why Ken Ishiwhata did this, cant remember the full details but had to do with RF, and eddy current shielding and magnatism. Sorry guys I already tried google but still havent found it, Ill try some more. The signature series is Ken s no compromise series of hifi equipment. Just like lead is the best shield for radio active material so is copper and aliminium for electrical fields. If John or PMA have knowledge on this they can explain the properties of these metals which makes them such good electrical shields, I cannot remember now what it was, maybe because its past 1am here.
I think that I understand why we did not appear to have any significant RFI from the Sutro tower. It is a close call, BUT if you look at a map of the SF Bay Area, find the location of the Sutro TV tower, the Golden Gate Bridge, and the location in Sausalito for the Burning Amp, you will find almost a straight line. I suspect that the bridge casts a shadow on that location. I KNOW that Tiburon does not have that shadow, because when I lived there, I could see both the GG Bridge and the Sutro tower at the same time, clearly separate from each other. Does anyone remember looking toward the bridge and seeing the Sutro tower?
john curl said:
For the record, and for my own personal glory and eternal edification here on the web, the " unshielded teflon silver wire of the highest quality that we could find" is my wire that I use in my Silver Lightning interconnects, and was supplied by me to Bob Crump and John...
<bow>I need the self applied ego boost right about now...
Thanks for the endulgence...
_-_-bear
I think that it is important, once again, as to why many hi end audio designers think that wire quality is important. The same factors concerning wire can also be applied to connectors, component leads, circuit board materials and construction, and solder.
A quick bit of history:
When I first started in electronics 50 years ago, usually 2 sorts of wire were commonly available for wiring a circuit. These were 'doorbell wire' , usually a single plastic covered wire for hooking up low voltage circuits, primarily, and 'zip cord' which is composed of two 18ga, parallel copper wires, molded together, and used primarily for 120V lamps, and radios.
For several years, that is all that I normally used for general projects. It seemed to work, so why do better?
Why should we bother with teflon, silver, or exotic geometries? Please, any responses should be rational, based on experience, or scientific evidence. I hope that we can avoid 'mindless' attacks that are so prevalent on the internet, in general, on this subject.
This is one of the fundamental reasons that the Blowtorch preamp was built, rather than some other approach. You might say that the Blowtorch case is a safe place to place quality, shield free, wire. Plastic, steel, or super thin cases, just won't do for this application.
A quick bit of history:
When I first started in electronics 50 years ago, usually 2 sorts of wire were commonly available for wiring a circuit. These were 'doorbell wire' , usually a single plastic covered wire for hooking up low voltage circuits, primarily, and 'zip cord' which is composed of two 18ga, parallel copper wires, molded together, and used primarily for 120V lamps, and radios.
For several years, that is all that I normally used for general projects. It seemed to work, so why do better?
Why should we bother with teflon, silver, or exotic geometries? Please, any responses should be rational, based on experience, or scientific evidence. I hope that we can avoid 'mindless' attacks that are so prevalent on the internet, in general, on this subject.
This is one of the fundamental reasons that the Blowtorch preamp was built, rather than some other approach. You might say that the Blowtorch case is a safe place to place quality, shield free, wire. Plastic, steel, or super thin cases, just won't do for this application.
The reason that I kept this topic open is to inform others here of what (little) I have learned about wire that many here may not know.
First, the history of hi end wire:
The first time that I actually saw the use of wire priced above Belden in audio designs, both pro and consumer was with Mark Levinson. He was using solid core Teflon covered wire in all his projects in 1973, when I started working with him. He had learned this from Dick Burwin, one of the founders of ADI, and most probably for reliability, primarily. Stranded wire, which was often used, was not necessary for the interiors of audio equipment, because it is not often bent, after installation. The added stiffness of the solid core cable made it easier to have the wire support itself without drooping. More aesthetics than sonic quality.
Interconnect cables were really cheap and dirty, using tin coated RCA connectors, and HIGH CAPACITANCE/meter cable (because the insulator material was so cheap). Then a Tweak outfit who also supplied STAX headphones and various record cleaners, put out a 'better' cable, called 'Gold Ends'. I don't think that cable technology was primary in this upgrade, except for better looking and fitting connectors. We still used them, BUT most of the RCA female jacks that these connectors connected to were TIN, not GOLD plated. This caused another set of problems, because gold and tin do NOT like to connect to each other. Therefore many audio manufacturers tried to find a way to get gold plated connectors, rather than tin connectors. Guess what, there were NO RCA gold plated connectors! What a concept. We even tried to do it ourselves, with mixed results, taking a normal quality RCA connector and sending it out to be gold plated.
Then came really good RCA connectors from Japan. So good, that we still use them, or their clones today. At least this problem was solved.
By 1978, we could really buy good connectors and even SILVER coax cables, terminated by quality RCA connectors. Were we in audio nirvana at this time?
First, the history of hi end wire:
The first time that I actually saw the use of wire priced above Belden in audio designs, both pro and consumer was with Mark Levinson. He was using solid core Teflon covered wire in all his projects in 1973, when I started working with him. He had learned this from Dick Burwin, one of the founders of ADI, and most probably for reliability, primarily. Stranded wire, which was often used, was not necessary for the interiors of audio equipment, because it is not often bent, after installation. The added stiffness of the solid core cable made it easier to have the wire support itself without drooping. More aesthetics than sonic quality.
Interconnect cables were really cheap and dirty, using tin coated RCA connectors, and HIGH CAPACITANCE/meter cable (because the insulator material was so cheap). Then a Tweak outfit who also supplied STAX headphones and various record cleaners, put out a 'better' cable, called 'Gold Ends'. I don't think that cable technology was primary in this upgrade, except for better looking and fitting connectors. We still used them, BUT most of the RCA female jacks that these connectors connected to were TIN, not GOLD plated. This caused another set of problems, because gold and tin do NOT like to connect to each other. Therefore many audio manufacturers tried to find a way to get gold plated connectors, rather than tin connectors. Guess what, there were NO RCA gold plated connectors! What a concept. We even tried to do it ourselves, with mixed results, taking a normal quality RCA connector and sending it out to be gold plated.
Then came really good RCA connectors from Japan. So good, that we still use them, or their clones today. At least this problem was solved.
By 1978, we could really buy good connectors and even SILVER coax cables, terminated by quality RCA connectors. Were we in audio nirvana at this time?
As it would be OT here, I made several remarks on today test of Parasound Halo JC-2 and Dispre II in:
http://www.diyaudio.com/forums/showthread.php?postid=1647285#post1647285
http://www.diyaudio.com/forums/showthread.php?postid=1647285#post1647285
As I have said before, in 1978, I purchased a 1 meter set of cables in Japan that used quality connectors and SILVER WIRE. Although this cable cost me 5-10 times more than a usual interconnect cable of the same length, I bought it just to try it. I didn't expect much, but what I got was DISAPPOINTMENT! Yes, these cables didn't sound good, they actually sounded harsh, yet I could not measure anything down to -100dB (the limit of my test equipment at the time)
I loaned them out to others, with the same dissappointing result. What could be wrong? This is completely opposite what many would insist on, even if there was no objective difference sonically between the cables. After all, should not a pretty, well made, expensive connector sound better, rather than worse?
While you ponder this, I will try to put together some information from a PHYSICS point of view, rather an ENGINEERING point of view, that might, at least, show where some potential differences in materials and construction exist that are often not recognized.
I loaned them out to others, with the same dissappointing result. What could be wrong? This is completely opposite what many would insist on, even if there was no objective difference sonically between the cables. After all, should not a pretty, well made, expensive connector sound better, rather than worse?
While you ponder this, I will try to put together some information from a PHYSICS point of view, rather an ENGINEERING point of view, that might, at least, show where some potential differences in materials and construction exist that are often not recognized.
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