Rogue Audio RP-1 DAC use

I just added a Rogue RP-1 to my system. I use a Bluesound Vault 2 as a music server. Befor the Rogue I have been able to tell the difference in different DAC's I've had. My equipment is Emotiva XMC-1, Oppo 105, Bluesound Vault 2, AV123 strata Mini speakers and a SVS 300bp subwoofer.

I've compared the Oppo 105 to the Vault and the Oppo was definitely better, I've also compared the Vault to the XMC-1 and the XMC-1 was better.

Since installing the Rogue RP-1 they all seem to sound the same, even borrowed a Schiit Bitfrost. Again I could not hear a difference. So I have just simplified my setup and I'm just using the the RCA out from the Vault to one of the RP-1 inputs.

Just wondering if I'm doing something wrong

Thanks