Re: Apple IIGS Stereo Sound Card - Interest?

[Drew <goggledrew@gmail.com>]

> Hi Drew,
>
> Nice looking card! The fabricator has done a great job on the matt
> green.

Thanks :-), shame it didn't work properly first go :(, but all part of
the fun :-)

> As for noise, I usually find power is a key contributor for noise.
> Some low noise linear regulators (10uV/RMS) with high PSRR can really
> make a difference, especially if you have stage gains around 20db and
> above. Its amazing how much supply noise gets amplified up into the
> output. Killing it at the source is easier than removing it from the
> output

Do you add the linear regs to the  board itself ?

> Do you know for sure its white noise? (hiss) - is there any sign of
> digital noise? When the floppy drive operates, do you notice any
> change in the noise level for example?

Tonight I am going to connect a floppy drive and see if that adds
noise, and also switch the outputs of left and right from the MC1402B
chip to see if the white noise follows. If it does then at least i can
eliminate half the circuit i.e the TL084 Amp part. I still have the
bread board made up, so at least i have something to play with still.

Also going to run through the circuit to see if i can see any obvious
issues.

Thanks
Drew