[colug-432] Record from Cassette

[R P Herrold]

On Wed, 12 Aug 2015, Rick Hornsby wrote:

> Your laptop's audio input is probably not set up to be a line in[1]. That jack connects to audio hardware that's designed for a microphone.  Sometimes you can use a mic-in as a substitute for a line in, but more often I've found that it doesn't work properly.
> 
> As far as "not getting any sound" that's most likely because the generic software (and/or drivers) won't let you both record an input and simultaneously output that sound through the laptop.  I believe some software can do that, but it may also depend on your audio hardware being full duplex capable.

> [1] http://wolfcrow.com/blog/what-is-the-difference-between-line-level-and-mic-level/

nice find URL.  Should be simple enough to put together a two 
channel level shifter with a couple 941 op amps, isolating 
input capacitors, and a resister set voltage bridge

Minimal gain / loss too, for extra points to avoid distortion 
effects doing it in a later stage.  Audio frequencies are so 
low that shielding will matter much more than RF high end 
linearity

The old Don Lancaster Op Amp Cookbook coverd all this.  I"ve 
corresponded with him in the last couple years and will see if 
he put it on line once Sams went under and the copyright 
reverted

Surely this has been done already and a minimal 2 channel 
mixing board exists at a Mucri-center or Radio Shack?

-- Russ herrold