Splitter

Just put AQ double connector on the output of my phono section in order to record to a newly acquired reel to reel.  I seem to be gearing an increase in upper mids...a little brightness I could do without.
Is it all in my head?  Can anyone suggest a reason why there might be a change in tonal balance? This seems to happen even when the signal is not passing through the decks circuitry; so it's flowing the same path as always.  Solid metal (no cable) splitter have a substantial effect?