I need a submixer to premix the outputs from my guitar synths, hoping for a small compact 4 channel mixer with balanced stereo TRS inputs (so 2 TRS jacks per input channel plus 2 for output) - anyone know of such a thing? I found a small one from Behringer that did 3 channels, but I want 4. Everything seems to be RCA inputs or unbalanced TRS stereo input...