peter@sugar.UUCP (Peter da Silva) (12/23/87)
I've just turned off the 5khZ audio filter in my buddy's 2000. Incredible. So, can anyone post the docs on cutting the filter out in the 1000? -- -- Peter da Silva `-_-' ...!hoptoad!academ!uhnix1!sugar!peter -- Disclaimer: These U aren't mere opinions... these are *values*.
dml@loral.UUCP (Dave Lewis) (12/25/87)
In article <1301@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes: >I've just turned off the 5khZ audio filter in my buddy's 2000. Incredible. So, >can anyone post the docs on cutting the filter out in the 1000? That's not all -- the output level from a 1000 is pitifully low. I have to turn my stereo WAY up to get decent sound from the Amiga's audio outputs. I'm thinking about installing an LM1303 stereo preamp in there somewhere. A little equalization, a level control, switchable noise filter.....
dillon@CORY.BERKELEY.EDU (Matt Dillon) (12/26/87)
> That's not all -- the output level from a 1000 is pitifully low. I have to >turn my stereo WAY up to get decent sound from the Amiga's audio outputs. I'm >thinking about installing an LM1303 stereo preamp in there somewhere. A little >qualization, a level control, switchable noise filter..... It is? I haven't noticed... it goes through my stereo just fine. Perhaps there is something else wrong. -Matt
cheung@vu-vlsi.UUCP (Wilson Cheung) (12/27/87)
> >thinking about installing an LM1303 stereo preamp in there somewhere. A little > It is? I haven't noticed... it goes through my stereo just fine. > Perhaps there is something else wrong. > -Matt Well try comparing the Amiga's sound at the third notch on the volume control then compare it to music from your FM tuner or turn table. The Amiga volume is considerably less. -Wilson
grr@cbmvax.UUCP (George Robbins) (12/28/87)
In article <1509@loral.UUCP> dml@loral.UUCP (Dave Lewis) writes: > In article <1301@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes: > > >I've just turned off the 5khZ audio filter in my buddy's 2000. Incredible. So, > >can anyone post the docs on cutting the filter out in the 1000? Basically jumper between pins 14 and 3 of U5G and pins 8 and 5. This is a TL084/LF347 or equivalent located just in front of the power connector and under the rear edge of the RAM/ROM tower. For dynamic control, you can adapt the circuitry used in the A500/A2000, but you will probably need to disconnect the LED driving circuitry to get and adequate negative swing for the control signal from the 1488. > That's not all -- the output level from a 1000 is pitifully low. I have to > turn my stereo WAY up to get decent sound from the Amiga's audio outputs. I'm > thinking about installing an LM1303 stereo preamp in there somewhere. A little > equalization, a level control, switchable noise filter..... I't not so sure about this. Remember that the A1000 has provides software controllable "volume" settings and that not all software is going to set these to full volume. In any case the actual output level is set by the ratios of R1/(R1+R2) and R3/(R3+R4). If you want lots of output for some special application, simply apply the old wire clippers to R1 and R3... Remember than anytime you disable the anti-aliasing filter, it is your responsibility to provide some kind of filtering appropriate to the sampling rate and characteristics of the output amplifier. Don't blame us if you blow your tweeters or turn your Amiga into a giant ultra-sonic dog whistle... Just because you can't hear the high frequency components of the signal doesn't mean they aren't there. -- George Robbins - now working for, uucp: {uunet|ihnp4|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
peter@sugar.UUCP (Peter da Silva) (01/02/88)
In article <3020@cbmvax.UUCP>, grr@cbmvax.UUCP (George Robbins) writes: > In article <1301@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes: > >can anyone post the docs on cutting the filter out in the 1000? [ instructions and other stuff deleted. Just hit 'p'. ] > Remember than anytime you disable the anti-aliasing filter, it is your > responsibility to provide some kind of filtering appropriate to the > sampling rate and characteristics of the output amplifier. Don't blame > us if you blow your tweeters or turn your Amiga into a giant ultra-sonic > dog whistle... Just because you can't hear the high frequency components > of the signal doesn't mean they aren't there. Any way to instead of *cutting* the filter, change its frequency response? I can hear pretty much all the way to 20 KhZ (monitors really bug me sometimes but I've gotten used to it), so how would I change it to (say) an 18 Khz filter? Just change a resistor somewhere? -- -- Peter da Silva `-_-' ...!hoptoad!academ!uhnix1!sugar!peter -- Disclaimer: These U aren't mere opinions... these are *values*.