How to get balanced inputs working

Connections between dac and cdp is rca

It appears, as is typically the case, that the XLR/RCA switch on the Audio Horizons 3-series DACs selects between the XLR and RCA digital INPUT connectors, and has nothing to do with which analog output connector is being used. The XLR and RCA analog output connectors are presumably driven simultaneously, as Brf indicated.

So the reason that you hear nothing when "XLR" is selected is that nothing is connected to the XLR digital input connector. The MBL preamp has nothing to do with the issue.

The bottom line: Hey, no problem!

Regards,
-- Al

Its a shame That I'm having a problem with the mbl balanced , because that's where the audio horizon shines more low level detail ,better tmber in voices ,larger soundstage , overall better musicality ,as the original hook up was with the sugden preamp in xlr and was awesome and the sugden is no mbl so I assume all these nice harmonic textures were from the dac

No the audio horizon dac was working in xlr with another balanced preamp the sugden and worked fine in xlr

If you are saying that with the Sugden preamp everything worked well when the digital input to the DAC was provided on its RCA input connector, while the input select switch on the DAC was set to select its XLR input connector, that makes little sense.

If that is really what was happening, the only explanations I can think of are that either the input select function of the DAC is malfunctioning, or its design is such that there is some amount of "crosstalk" (unwanted coupling) between its two digital inputs. In either case the condition would presumably be very marginal, such that small differences in grounding conditions that may occur depending on which preamp is connected would mean the difference between the DAC working and not working.

That all seems very farfetched, but those are the only explanations that occur to me if the facts you have reported are accurate.

In any event, if you are inputting to the RCA digital input on the DAC, its XLR/RCA input select switch should be set to RCA.

Regards,
-- Al