Absolutely. The Jolida integrated tube amps use a 100% passive input stage going into the source, volume balance then into the circuitry.
If you don't mind having these controls in the signal path, you can run a preamp into any one of the line inputs. Obviously you would have to set the Jolida volume at an acceptable level, usually around 1 o'clock and then you can maintain volume from your choice of preamp.
It is best to bypass the controls as not to have two volume pots in the signal path but still very functional.