Subject: Re: [linux-audio-dev] [ann] unmatched - a LADSPA amp tone
From: Tim Goetze (tim_AT_quitte.de)
Date: Tue Oct 29 2002 - 15:20:32 EET
Steve Harris wrote:
>On Tue, Oct 29, 2002 at 12:18:23 +0100, Frank van de Pol wrote:
>> looking at the distorted signal it look to me like an amp that is clipping,
>> but it's power supply can't maintain the voltage (eg. relatively high
>> impendance on the powersupply/series resistance). While +ve or -ve side of
>> the output pair is used it drains the capacitor from the power supply, hence
>> the exponential slope from 'spike' till drop.
>
>Aha, great. I was thinking about how to rewrite the valve rectifier, and
>it occured to me that my revised algorithm would output something that
>looked like that in extreme cases.
>
>That means 1) we're nearer to Tim's shape, and 2) my alg. is more or less
>correct 3) we may not need to mess about with chebies.
1 + 2 + 3 = great. :)
i've uploaded another image showing how the line output from
the amp changes as the incoming sine increases in volume:
http://quitte.de/3x-driven.gif
admit i hope that frank's explanation holds, and that the
valve_rect can be made to produce similar shaping.
tim
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