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The answer depends upon the output characteristics of the preamp (or any other amp), really. Since that mic pre is made to replace the mic pre in a console or other interface, I would use the TRS 1/4" Line input to the DP machine and adjust the trim pot accordingly. The ART preamp probably has an output gain control. If you place the trim pot on the DP machine to 1 o'clock that will be approximately unity gain. Start with the ART preamp output gain all the way down and with the DP trim pot at 1 0'clock, bring up the ART output gain until you get the level you need.