Headphone jack adaptor question.

ASL makes a transformer based device called, IIRC, Signature Tools, that takes a line level signal, runs it through a transformer and has headphone jacks. It is about $125, I think. Need to have a pretty high voltage pre-amp to drive it. Or take the extra pre-out and use it to drive a headphone amp as Elizabeth suggested.

Sfar- Close, but no cigar: that unit has speaker level inputs. The one I am talking about is this one:
Reference Tools the unit I had was defective out of the box, but was repaired. ASL in the past had some qa/qc issues, but others have said that those days are past.
And to the fine gent who asked about my moniker; you were close. I am a wetland scientist and often spend several days a week marking wetland boundaries and looking at the creepy-crawly things that live therein. But not in FL. I am snowbound in CT these days.

Md- That is the way it is typically done, putting a headphone amp in the tape loop. Many also have a loop out, so you can still insert a tape deck even if you only have one loop.