How to turn on Unity Gain on Pre Amp

The best way to hear what the LEEDH processing is really doing is to bypass your preamp completely. Going forward, I intend to only use a preamp for my vinyl front end. Digital is going directly into the amp.

thanks for input all, i’ll check HT bypass. I am running dual subs so eliminating the pre is not a great option. at this point i’m wanting get the best test i can with the leedh with preamp in place and see what i hear. I can’t help it go down the rabbit hole a bit but the truth of the matter is I would prefer to maintain using my preamplifiers remote control as opposed to the iPad through the lumin app or roon app. if I like what I heard I can investigate the LUMIN remote but I’m not sure how that would integrate with and everything though?

Can't find HT bypass mentioned in the owner's manual. Is tone bypass the same thing? below is the section from the manual 

Tone Bypass Press the Front Panel Tone BYPASS Push-button to remove the C2500 Tone Circuitry from the signal path for the currently selected Input Source. The LED above the TONE BYPASS Push-button will illumi�nate. Refer to figure 50. The C2500 remembers for each selected Input whether the Tone Control Circuit�ry is deactivated. To reactivate the Tone Control for the currently selected Input Source press the TONE BYPASS Push-butto

Not the same thing....

Tone bypass is not HT bypass, its function is to deactivate tone control setting.

On the C2500, " Passthru " is HT bypass. To activate passthru, you need to sent a 12Volt single by an external source to the back panel "power control" "Pass-thru" jack via a 3.5mm stereo cable (see owner's manual page 4).

Once the "Passthru" function is activated, all front panel control knobs and buttons including volume control will be deactivated except the "output 1/2 buttoms" (see owner's manual page 25), and the volume level will be automatically set and lock into unity gain (70%?).