PCBgogo

Hi folks - anyone here with knowledge of tape recorder circuitry?  I know that  tape recorders employ an AC bias oscillator that is mixed in with the incoming signal on it's way to the record head. The bias oscillator also goes to the erase head. Now - I would like to modify a tape deck and add a switch that would disconnect the erase head, while recording, for certain applications. This happens to be in a Marantz pmd-222 cassette deck but the question is more general. 
Since the bias oscillator goes to both the erase and record heads while recording, will the recording quality be affected if I disconnect the erase head with a switch? I'm looking for a way to cut off the erase function while maintaining quality.  ( yes, I do realize that I will get sound-on-sound when I do that) 
If the two heads are designed to always be there as a required inductive load, then I may have to think of another way. For example, I could get another erase head and place it in another part of the machine (shielded) and away from the tape and simply switch between the two heads to maintain the same effective circuit. But is this necessary? Any other ideas? Can I switch over to an inductor of the same "value" as what's in the erase head but without the magnet? 
Of course I will probably experiment, but thought I'd see if anyone has experience in this already
I'm attaching the portion of the schematic that shows the bias circuit and its connections to the erase and record heads. Note the transformer and its different windings that go to the two heads.
Hope this helps

Thanks!