If memory serves, the Cleanbox Pro does not provide galvanic isolation, so you may need custom XLR cabling, and parts quality was also found to be rather lacking (carbon film resistors even in the balanced input stage, so with their generally wide tolerances of 3-5% don't expect any miracles from CMRR even in a best-case scenario). I won't be surprised if the construction is close to 20 years old.
What you would need basically is a balanced receiver, which is the kind of thing that can be integrated into an existing device fairly easily but gets really annoying if you have to add one externally. First there's the matter of powering the circuitry, and then you'll probably want to provide an extra ground connection for the XLR shields that's independent of audio ground, to be hooked up wherever shield currents are bypassing the complete unbalanced audio path (otherwise you'll have issues with AES48 compliance). It's all a bit ghetto.
If you can't be bothered with AES48 compliance (but consider custom ground-lifted XLR cables a valid option), then you might as well be using an ordinary compact mixer (the kind that comes with an external transformer power supply).
Pure transformer boxes often are fairly sensitive to output loading, so that's something else to keep in mind. The PC-2XR datasheet recommends 47 kOhm (or higher) || 150 pF (or less).
What kind of specific application / component pairing did you have in mind? Knowing that might make it easier to find a suitable solution.
The right tool for the right job and you'll know that it will be just fine.