I was a new technique for laying down tracks. I wanted to put in a raw, unprocessed guitar tone, then output that into one of my heads to play during playback. It worked, kind of, but there were too many issues with the playback to be able to use it.

Signal:

Guitar --> Lexicon Alpha Instrument jack --> Garageband raw track

For the output:
Garageband raw track --> Lexicon Alpha (L Mono) line out --> Marshall JMD input jack.

The issue is a lot of noise. The signal I get from the guitar input jack is not hot enough on the track to make any difference. Also, I think the Lexicon alpha is a bit short on features to really be able to do this properly. I'd like to record a raw clean track, then put it through the two amps. That way I can compare the two amps side by side, or lay down two guitar parts without having to play twice, perfectly, in time.

I was inspired by a video by Ola Englund where he demo's a bunch of amps and it's the same track he just routes through different amps.

I also tried to get both amps working, but when I connected into the Crate BV120 head, I got a high-pitched squeal in the background that was way too audible. Another no go.

Are there buffers out there or input/output devices that will allow this to be performed?