I just bought a relatively cheap and small mixer. The post aux send and pre monitor send are both mono. Is this normal?

Another quick question, when I send out of the tape outs back to my edirol sound card it goes mental, the sound is horrible and the clip indicators are on permenantly.

I think this is because I am playing audio out of the soundcard into the mixer, and the tape sends are sending it straight back in. There is no way to disable the tape send except to unplug the input leads.

Is there a better way to do this? The monitor sends are only in mono.