Try the alternate output and bypass the tubes? I have a feeling they introduce a lot of noise.
Also, you have to be fairly sure that there isn't too much noise in your samples in the first place - any high EQ, compression, or distortion will bring it out even more.
Current Gear: Kronos 61, RADIAS-R, Volca Bass, ESX-1, microKorg, MS2000B, R3, Kaossilator Pro +, MiniKP, AX3000B, nanoKontrol, nanoPad MK II,
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