Last Updated: 20050512, tendelooSaturday, May 28, 16:00 — 17:30
Chair: Reinhard Sahr
E-1 The Self Compensated Output Power Transformer (SC-OPT) Theory and Properties—Aristide Polisois, A2B; Pierre Touzelet, Société d'Etude et de Réalisation de Moyens d'Essai (SEREME) - Bondoufle Cedex, France
Conventional OPT (CO-OPT), when used for single-ended tube amplifiers, are a great inconvenience due to the anode quiescent current, which reduces the core magnetic flux capability, for the AC magnetic flux, before the core saturation. Usual solutions applied to solve this problem are based on air gaped magnetic cores, with a large core cross section. Resulting performances are generally satisfying but lead to large, heavy, and expensive OPT. This paper introduces a new concept of OPT: the Self Compensated OPT (SC-OPT). Its aim is to remove the above problem. The DC magnetic flux, due to the anode quiescent current, is self-compensated, offering to the AC magnetic flux, the whole core magnetic flux capability. As a result, and for equivalent magnetic performances, SC-OPT can be made smaller, lighter, and less expensive.
Convention Paper 6346 (Purchase now)
E-2 Universal System and Output Transformer for Valve Amplifiers—Menno Van der Veen, Bureau Vanderveen - Zwolle, The Netherlands
Vacuum tube amplifiers have many different topologies such as single ended (SE), push pull (PP), paralleled push pull (PPP), or cathode follower (CF). These topologies and all of their variations are placed into one general system. This gives clear insight into the coupling between vacuum tubes and the output transformer, which functions as an impedance converter between the high impedance vacuum tubes and the low impedance loudspeaker. A new universal output transformer is proposed that can be used for all these topologies of tube amplifiers. This transformer is discussed and results are shown with twenty different amplifiers from the general system.
Convention Paper 6347 (Purchase now)
E-3 Practical Program Loudness Measurement for Effective Loudness Control—Jeff Riedmiller, Charles Robinson, Alan Seefeldt, Mark Vinton, Dolby Laboratoriess - San Francisco, CA, USA
The broadcast, satellite, and cable television industries have been plagued for years by the inability of personnel to reliably measure and, thus consistently, control program loudness utilizing traditional measurement devices and methods. As a result, most listeners feel compelled to make adjustments to their television volume controls (in the home). A recent survey of channel-to-channel and program-to-program level discrepancies confirms that the current practice is unacceptable to listeners. In this paper we propose and describe several measurement techniques designed to reliably measure program loudness and enable effective loudness control.
Convention Paper 6348 (Purchase now)
©2005 Audio Engineering Society, Inc.