FROM VIENNA: IS THERE MAGNETIC CREAM?
The Triode Guild is very active in Vienna, which is a city that has thousands of
variations in cream, which explains their love of triodes. Helmut Mueller-Guttenbrun,
whose tribal name is Hymi The Cynic sent me this article which indicates just how
senstive we are all becoming to magnetic forces.......
The superiority of oxygen free copper or silver needs no further discussion if you look at the microphotos of normal - cold drawn - copper wire and its millions of crystal boundaries. One really needs not beeing Einstein to know that smooth electron flow is always better than sqeezing the poor electrons through a wire with lots of little diodes -like the turbulent flow of water through a dirty tube with lots of lime deposit. Didnt you once finely polish the intakes of your hotrodded engines?
Interestingly there are only few OPT manufacturers who offer windings with age annealed copper or oxygen free copper. The Ohno Continuous Casting Process with preheated die was recently reintroduced in America by a cable company named Harmonic Technology. But these guys seem only to be interested in selling audio cabling for big money, not spools of laquered copper wire (of OCC quality) to OPT winders. I think this could be part of a quantum leap in OPT quality!
Another point of commercial compromise lies in the core material and geometry.
I believe firmly that the use of advanced core materials and ultrapure copper wire will lead to much superior OPTs in the future. But you mentioned it: Only if WE start demanding these materials.
It would be fine to see other american OPT winders than LeFevre dealing with these things. One of the virtues of MagneQuest is they are taking the risk of trying new paths, not only tumbling along in the dust with all the other mainstream - guys.
Another firm believe of mine - although I have no personal proof for this - is the theoretical advantage of splitting the OPT into a big Choke for lots of Hys for good bass and a small sized OPT with no dc to cope with. This OPT can be optimized for sound quality - with nickel or amorphous core - and a non resonant high q condenser (paper in oil) in the ground leg should do no bad things - as grego Sanguinetti reports in SP#15.
Back EMF: If you are using a big woofer with heavy membrane and coil and soft surround for low resonance, working into an undamped reflex enclosure and you want to drive this monster with a single 300B you are likely to get into bass problems. Its like a Vespa 50cc engine in a cadillac. We tried driving a 15 inch PA woofer with a single 845 and out came disastrous slow and contourless bass! Anybody who tried it , knows these restrictions. Anyway, with system fine tuning one can compensate some of these defects but dont think you can reinvent the laws of physics.
Homogenity of multiple Driver speaker Systems: The shared experience of some Viennese Horn people (with me) is that time alignment between drivers is critical, but the uniformity of directionality ( in the crossover region )is another very important parameter for good sound. The combination of midrange horns with ONKEN enclosures or any other direct radiator is always inferior to a woofer with a short horn - like Altec A5 with alnico driver. Thats a logic explanation for so many people happily living with these speaker monsters, regardless of the missing two octaves. Not to mention that the woofer needs to be fast!