Head Differences...

[National]

Hi there,

I have an unusual question on heads - PAL vs NTSC, reason i ask is that ive seen a model of VCR that in PAL format specifies a different upper and lower cylinder than the NTSC version, upon query no one could tell me why - anyone know of the difference here? as far as i can tell all the angles are the same, are the gaps different / coils etc? i initially thought cylinder speed would have been the only difference.

Having said that, ive seen NTSC and PAL using same cylinders on lower models.