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TIMTAPE · 21st May 2020, 11:39 pm

After such a mod or unmod the repro head should really be checked for the centring of the tape contact patch (left to right) on the head gap. You can't see it because the tape obscures it. Ideally the head is first relapped to remove the "flat" caused by previous tape wear. With the A77 these adjustments require removal of the control panel cover so you can see the head clearly. My trick to check the contact patch is to draw a patch of black with a whiteboard marker right on the head face, play a tape for a few seconds, remove tape and then inspect. The contact patch is of course where the black has been removed. The Revox single screw mounting allows for
minute rotation. It's a fiddly business but results in optimal contact and therefore response. The long term payoff is even wear and so long life on the expensive and these days harder to source heads.

21st May 2020, 11:39 pm	#25
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,969	Re: Revox A77 issue After such a mod or unmod the repro head should really be checked for the centring of the tape contact patch (left to right) on the head gap. You can't see it because the tape obscures it. Ideally the head is first relapped to remove the "flat" caused by previous tape wear. With the A77 these adjustments require removal of the control panel cover so you can see the head clearly. My trick to check the contact patch is to draw a patch of black with a whiteboard marker right on the head face, play a tape for a few seconds, remove tape and then inspect. The contact patch is of course where the black has been removed. The Revox single screw mounting allows for minute rotation. It's a fiddly business but results in optimal contact and therefore response. The long term payoff is even wear and so long life on the expensive and these days harder to source heads.