On Sep 30, 2008, at 3:55 PM, Mr Ian Primus wrote:
I forget what their rationale was for not
connecting the computer to
the hi-fi directly, but there was a warning that you could damage
the computer. (Probably, they were afraid of people hooking the
_speaker_ outputs into the poor little computer, instead of the line
out)
The primary reason is that it will only work in a handful of specific
configurations, and assuming that everybody with a turntable at their
disposal is able to comply is not really a sound business decision.
There are only a small number of standalone turntables I am aware of
which had (have) normal line outputs. The vast majority of them
require preamplification (and equalization) if they are to be used on
a line input. The "phono" input on many amplifiers provides this
preamplification; in this case the amplifier's line out or tape
monitor output may be connected to the computer without consternation.
I cna think of a problem with doing that. If I remmeebr the CoCo well, it
was fairly 'touchy' about the inptu signal level on the cassette port.
No worse than most otehr machines, but you still had to fiddle with the
volume control on the cassette recorder to get it to load.
On 99% of hi-fi amplifiers, the line out/tape out sockets are not
affected by the setting of the volume control. So there's no easy way to
adjust that level. Copying the record to a cassette and then loading it
in the normal way lets you use the cassette recorder volume control to do
this.
Of course it's not hard to rig up a potentiometer and if necessary an
op-amp to boost the signal (I seem to remember the CoCo likes about 1V on
the input, most tape outputs on hi-fi amplifers are around 100mV). But it
might be more work than using a cassette recorder.
I suspect dividing down the speaker output of the record player
(phongrpah?) (a couple of resisotrs) and feeding that into the cassette
input would work well. But if you got it wrong anf the amplifier was a
high-power one it might fry the CoCo's input. And if the amplifier was
one of those bridge-output ones (neither side of the speaker groudned),
you might fry _that_.
-tony