Echo II Soundcard

[romeo@anet-dfw.com (Romeo)]

Hi. I recently bought a IIgs that has an Echo II card in it. It seems to be 
some sort of mono soundcard. Is this thing worth having in a IIgs? I thought 
the IIgs had awesome sound without need of an external soundcard? I plugged 
headphones into the "Echo speaker out", and got a lot of "hum". Are these 
things supposed be that noisy? 

Anyway, I don't have any documentation or software for it. Can someone tell me 
some more about this card; and does anyone have the software/manual they wanna 
sell?

Thanks,
Romeo
romeo@anet-dfw.com