I also use the Quartet into my iMac with Logic Pro and it works as expected

, the quartet sounds even more 'warm' and 'analog' when it comes to tracking guitar and/or vocals

The quartet sounds so warm and clean

If you're open to a non-iPad soundcard solution, I'd also HIGHLY recommend the UAD Solo Twin as it has onboard DSP for UAD plugins - the best sounding ones I've heard yet