In a message dated 20/05/2007 19:11:42 GMT Standard Time, caddyfam@... writes:
On your headblock are 35 tape
heads. That is there are 35 coils able to store energy. Assuming
you are demagging headblock removed from machine, a good practice,
the coils can pick up a residual static charge. Think of them if
you will as capacitors. So before you plug heads into preamp, they
need to be drained. This is what the resistor does, but you can do
the same thing by shorting out the lead at headblock and the head
receptacle on preamp with same results.
Dear All,
The thing that screws up head blocks is DC voltages as this can partially magnetise the heads, turning them into 35 tape erasors!
DC can be applied in several ways. The most common are testing the continuity with a meter and the residual charge that builds up on a preamp when the headblock is disconnected. For that reason a head block should never be disconnected or reconnected while the machine is powered up.
The other way to magnetise the heads is to switch off the demagnetiser while it is still in range...
When reconnecting the headblock short the input of the preamp (the edge of plug can be used) and then plug the headblock in without delay.
Regards,
Norm