The D-Two has a 6 dB level drop on the output compared to the input. There is no way around that.
Because of this, the D-Two is only moderately suited for usage as a line delay unit. We recommend either our dedicated D22 Broadcast Line Delay instead, or alternatively the M-One XL Multi FX Dual Engine Processor unit which can also be set up for line delay operation.
The M-One XL does not have a level drop on the output compared to the input.