Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!bagate!cbmvax!cbmehq!cbmger!peterk
From: peterk@cbmger.UUCP (Peter Kittel GERMANY)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A1000 filter
Message-ID: <1009@cbmger.UUCP>
Date: 25 Mar 91 14:26:23 GMT
References: <48599@nigel.ee.udel.edu>
Reply-To: peterk@cbmger.UUCP (Peter Kittel GERMANY)
Organization: Commodore Bueromaschinen GmbH, West Germany
Lines: 18

In article <48599@nigel.ee.udel.edu> Dickson@system-m.phx.bull.com (Paul Dickson) writes:
>> It it the audio-filter I am talking about.  If I am not totally
>> mistaken the low-pass filter on a A1000 is permanently on and it
>> can't be turned off as is possible on all the other Amigas
>> unless you do some hardware fixing.  In other words you are
>> stuck with a poor sound output.
>
>There is no audio filter on the A1000.  The filter was added to the
>other Amigas to reduce aliasing noise on the audio output, but can be
>turned off by software.

Sorry, but I fear you're wrong. In the A1000 schematics I have (the old
ones on one single sheet), there are definitely filters on both outputs.
They are built with 5-fold RC combinations plus an LF 347 OpAmp.

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk