Here's a picture of my initial musings:
As anyone with a IIgs will know the computer has a very good sound chip - eight independent channels..? Sadly Apple only gave the machine a cruddy mono internal speaker, but at least supplied a header for expansion. I hear the IIgs can sound pretty awesome with some decent output and stereo->multichannel output cards have been available for a looong time.
-Hard to come by
-Expensive for what they are
-Where's the fun in buying stuff if you can make it..?
I've got to admit I'm no electronics engineer and the multiplexing the IIgs's sound chip uses for it's output has been 'doing my head in' but I think I've finally got it and can hopefully get proper stereo out of it... for now.
The above layout basically takes input from the IIgs audio header, demux's it so four (I think) channels each go to Left and Right, but I have some decisions to make:
-Do I want it as a plug-in card or not? ATM I've covered both bases; the edge connector only picks up power so could be regarded as a waste of a slot, hence my including a power header.
-More importantly what about output?
...I could:
a) Add some caps and just leave it as a line-out - external powered speakers
b) Put in some amplification - headphones, internal speakers
c) add a 3.5mm stereo jack and/or a header
If anyone's interested I'd appreciate comments. For myself I'd go for:
-Keeping the option to plug in to a slot or tap lines for power
-Have a line out header and the option of a small Amp plus header for internal speakers... the latter much as my Mockingbird card utilising an el-cheapo Amp board off fleaBay.
*Edit*
So far so good?
*Edit*Edit*
By Jove I think this may be it:
...a bit of tidying, the option to add a potentiometer for volume control of the Amplified output and baring any obvious mistakes / suggestions I think a prototype is called for. I guess I'd better do a wire-wrap jobbie before ordering boards - still not sure I've sussed the multiplexing thing.
As anyone with a IIgs will know the computer has a very good sound chip - eight independent channels..? Sadly Apple only gave the machine a cruddy mono internal speaker, but at least supplied a header for expansion. I hear the IIgs can sound pretty awesome with some decent output and stereo->multichannel output cards have been available for a looong time.
-Hard to come by
-Expensive for what they are
-Where's the fun in buying stuff if you can make it..?
I've got to admit I'm no electronics engineer and the multiplexing the IIgs's sound chip uses for it's output has been 'doing my head in' but I think I've finally got it and can hopefully get proper stereo out of it... for now.
The above layout basically takes input from the IIgs audio header, demux's it so four (I think) channels each go to Left and Right, but I have some decisions to make:
-Do I want it as a plug-in card or not? ATM I've covered both bases; the edge connector only picks up power so could be regarded as a waste of a slot, hence my including a power header.
-More importantly what about output?
...I could:
a) Add some caps and just leave it as a line-out - external powered speakers
b) Put in some amplification - headphones, internal speakers
c) add a 3.5mm stereo jack and/or a header
If anyone's interested I'd appreciate comments. For myself I'd go for:
-Keeping the option to plug in to a slot or tap lines for power
-Have a line out header and the option of a small Amp plus header for internal speakers... the latter much as my Mockingbird card utilising an el-cheapo Amp board off fleaBay.
*Edit*
So far so good?
*Edit*Edit*
By Jove I think this may be it:
...a bit of tidying, the option to add a potentiometer for volume control of the Amplified output and baring any obvious mistakes / suggestions I think a prototype is called for. I guess I'd better do a wire-wrap jobbie before ordering boards - still not sure I've sussed the multiplexing thing.
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