Some facts about tape heads
Worn or not worn? That is the question.
Poor output sound quality, loss of heights, is many times considered to be caused by worn head. But is it really true? From my experience, usually it is not! There are many other more probable reasons, like wrong tape path setup, wrong azimuth, worn pinch roller, aged capacitors, poor electronics design, low quality head used, dirty head, etc.
So how does worn head look? For correct answer, head gap should be inspected under microscope. Many times, head that looks completely worn, is still good, and on the other hand, head that looks like new is worn.
Here are two examples:
1. Head from cheap walkman has several thousand of hours played. Here you can see how much material is removed.
But gap looks still good. It is worn uniformly and such head still performs well.
2. Here is another example. This is head from TC-D5M and it looks like new. But notice these small hollows, just on the place where gap is located. This head performs very bad. In one channel, heights are completely missing. I’ve seen tens of heads with this problem
How can it be fixed? Usually yes. Process is called head lapping. Correct lapping process is not simple, it requires right tools, lot of patience and experience.
How can head affect sound quality?
Yes, it can significantly affect sound quality. For example in personal cassette players world, those that have amorphous head, like Sony WM-D6C, WM-DC2, WM-D3, or Panasonic RQ-S50, RQ-S80 and some Aiwas have excellent sound quality, especially in HF range.
Which heads wear faster and which last long?
It is difficult to answer this question. Generally, newer amorphous heads used in TOTL cassette decks wear slower than permalloy or hard-permalloy heads. Also Ferrite heads and some Sendrust heads last longer. Some manufacturers, like Panasonic, Nakamichi, formed shape of their heads to wear uniformly and sound quality is not affected that much. It also depends on tape used. Some act like sandpaper. I would personally avoid using cheap cassettes.