Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!UREGINA1.BITNET!GORRIEDE From: GORRIEDE@UREGINA1.BITNET (Dennis Robert Gorrie) Newsgroups: comp.sys.amiga Subject: Re: Audio Filter on Amiga 1000 Message-ID: <8911121907.AA11158@jade.berkeley.edu> Date: 12 Nov 89 19:05:51 GMT References: Sender: daemon@ucbvax.BERKELEY.EDU Lines: 31 >While we are on this subject & I have never seen the A1000 schematics, >please answer the following question: > >Q: Are the stereo outputs that come out the 8 pin connector on the back of >the A1000 filtered? > >They don't sound like it, and their outputs are apparently not directly > >Anyone want to comment who has the schematics for the 8 pin plug? > >Thanks >Kent Polk - Southwest Research Institute - kent@swrinde.nde.swri.edu > Motto : "Anything worth doing is worth overdoing" I only have the schematics from the Amazing Computing mag. The don't show anything about the audio lines to the modulator connector. I don't have the a1000 schematics. But from looking at the motherboard, it appears that there the audio signals from Paula go strait go the U5G, the buffer/filter chip. It would appear external audio signals must go through this chip. All the variety of filter mods are basicaly done to this chip, including the A500 and A2000 versions. So, what ever sound difference you are hearing, it must be bypassing filters somwhere else. The article in Amazing Computing Vol3, Issue 3, mentions more filters. In particular, 2 of them right beside the audio rca jacks. Perhaps the modulator connection does not have these filters, and that is why it sounds different. (they are labeled c5 and c6 I think.) Than you for mentioning the second source of stereo output. I am sure most people forget about the modulator connection on their A1000's.