Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!ucbvax!gnh-starport.cts.com!whitewolf From: whitewolf@gnh-starport.cts.com (Tae Song) Newsgroups: comp.sys.apple2 Subject: Re: cheap stereo on a gs? Message-ID: Date: 28 May 91 03:38:51 GMT Sender: usenet@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 54 > To: gnh-starport!info-apple > From: prophet@oxy.edu (Dale Bruce LaFountain) > Subject: cheap stereo on a gs? > Date: 23 May 91 19:52:11 GMT > Organization: Occidental College, Los Angeles, CA 90041 > Size: 1192 bytes > > I am itching to get stereo sound on my GS, but I am very wary of buying > any more of Applied Engineering products. This is compounded by the > fact that the digitizing part of both the SB and AA are basically worthless > to me because of the noise in the samples. > > So, 1) are there any other stereo boards out there (is MDIdeas' card still > around?) or 2) how can I go about building my own? I remember seeing a > schematic posted a while ago, but I wasn't so hot on the idea of stereo > at the time (I also thought that AE made a good sampler/stereo card, too... > I guess that's what I get for thinking...:) But now, being summer, Um, I've worked on the stereo circuit... I'm the one actually who posted in the past on the net. If you're not happy with the SB, you might try the AA, which I understand has a 12-bit ADC, for sampling... I'll have to recheck AE's ad. I don't kno what you are actually expecting from the stereo circuit... actually it is a octo-phonic circuit (8 channel audio)... you still end up using the Ensoniq for sampling and you'll still endup with whatever noise you had with the SB. Perhaps what's needed on the GS is a high-pass filter to clean the clicking noise which I hear on the GS speaker in the Finder. I've fryied my Ensoniq since doing research on the Ensoniq... I'll post the schematics for the octo-phonic circuit, but you shouldn't expect much more than what you would get from the SB... the main reason for building the octo phonic was to check out the 8 channel sound... but you need 8 speakers... perferablely amplified ... 4 speaker was more practical, though. I just recently got a SB, but haven't had a chance to use, since my Ensoniq is fried. What I was thinking of doing is revising the original octo circuit and using the low-pass filters on the card... I didn't know how to design specific active filters, back then... actually, I still don't, even though I know more now than I did back then... anyways... if you want the circuit, I can email it. One of the things you might do with the SB... you might look for a replacement for the LF347 (the device # escapes me), with some other op amps... LM324... there a couple other types with similar function/pinouts... that would be one the things I would try out... if that doesn't work... I have one other thing I'd like to try which is place a 100pf cap across the +,- signal pins on the op amps... there's no garantee that any of this would work, and I definitely won't know til, I get a new GS sometime in the next 6 months. INET: whitewolf@gnh-starport.cts.com UUCP: crash!gnh-starport!whitewolf ARPA: crash!gnh-starport!whitewolf@nosc.mil