Tape Trail

Posted by jtkarma (A) on October 01, 2007 at 13:35:35

Thanks to all the great info here I lapped the record and play heads on my TEAC RTR. I had a friend come over who has lapped CPUs and he helped me with this little project.

We setup a board over a sink with a piece of plate glass. Above it was this crazy contraption, a sort of I-V drip with Photo-Flo and water that leaked onto the lapping surface. The actual lapping was interesting as we were trying to lower the outer portions of the head to match the middle. The play head was a quick job. The record head took longer as it had a severe groove.

I think we had some 1500 grit to start which seemed kind of wimpy to me but my friend's thought was that the slower the better. We then used two different grades of 3M lapping sheets. The heads certainly felt smooth to the touch.

Later we got the heads back on the deck and tried to align them. We were able to match the play head's position exactly as before. There were drops of red loctite I'm guessing on the screw heads so it was easy to see where it was before. We then listened to a tape and made some small adjustments that brightened the sound to a point we thought was good and yet had nice bass. Scientific eh?

The record head was a different matter, well that and the fact that we'd had a few beers by this point. For some reason we struggled to find the best alignment for the record head. My friend has perfect pitch, plays sax in bands, and can whistle three notes simultaneously. I couldn't hear differences in adjustments but he had me going nuts back and forth with the record head's position. Eventually we settled on a spot where it seemed snappy in the bass and nice highs. Just a tweak here and there can make a huge difference.

To recap, we listened to a store bought classical music tape for the play head. Then recorded and matched the sound coming from my tuner for the record head. At high speed the tape is very close to the source. In slow speed you can tell you're listening to a tape but it still sounds pretty darn good.

With this RTR I'm going to record classical and blues off of my tuner. Probably get a bulk eraser so that after I'm done listening to a tape a few times, I'll be able to reuse it.

Also, the stuck pinch roller is now working. Not sure what freed it up but it works all the time now.

I can see why there are all these RTR decks for sale on eBay for like $200. Dudes clean them up a little bit, free the stuck pinch roller and make some nice cash. I will never buy one of these decks because I know what I've done to mine. Good lord willing, my next deck will be cleaned and prepped by a reputable tech and probably cost something like $800.

For now though, I'm crazy happy with my $30 deck. Next steps, a test tape and oscilloscope.

Thanks again for all the help here.