Re: Sound of tube amplifiers (=?iso-8859-1?Q?Bramsl=F8w=2C_Lars?= )

Subject: Re: Sound of tube amplifiers
From:    =?iso-8859-1?Q?Bramsl=F8w=2C_Lars?=  <LBRAMSLOW(at)BK.DK>
Date:    Thu, 9 Jul 1998 11:18:08 +0200

Dear Linda + list, One likely physical explanation for the "warmer" tube sound, is the = type of non-linearity in tube amplifiers compared to solid-state amplifiers. The static input/output curves of tube amplifiers are asymmetrical, causing distortion products that are even harmonic (2nd, 4th etc..). These even harmonics are musically pleasant to the ear as they are in familiar intervals (2nd harmonic =3D 1 octave etc..). Furthermore, the tube amplifiers tend to saturate in a nicer way at high levels, known = as "soft" clipping. Transistor amplifiers, on the other hand, produce symmetric artifacts, both at zero-crossing and at clipping. The harmonic distortion is dominated by odd harmonics (3rd, 5th etc..), which are not like any musical interval. This is believed to cause the "cold" sound. At high levels, the amplifier will hit the power supply rails very suddenly, causing "hard" symmetrical clipping and eventually turn a sine wave = into a square wave. Hope this qualitative info helps.. Lars ------------------------------------------------------------- Lars Bramsl=F8w Bruel & Kjaer Skodsborgvej 307 DK-2850 N=E6rum DENMARK Tel (front desk): +45 45 80 05 00=20 Tel (direct): +45 45 80 78 55 (tone) 2663 fax: +45 45 80 40 82 email: mailto:lbramslow(at) web: ------------------------------------------------------------- McGill is running a new version of LISTSERV (1.8c on Windows NT). Information is available on the WEB at

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