Cassette decks when they left the factory or a service centre should have been aligned to a standard reference for the position of the record and play heads. Unfortunately they often weren’t all the same and over time the alignment can get drift, get knocked out or manual ‘fiddled with’ by an owner.

What this means is that unless you’re playing back your tape on the machine it was originally recorded on you may be getting the maximum quality as the angle of the head to the recording or azimuth will not be optimal.

Without calibration tones recorded at the start of the tape which is very unlikely on most domestic cassette tape recordings you must set the playback azimuth manually. A few high end tape decks, namely those made by Nakamichi, either had a easily accessed Azimuth adjust or could even automatically adjust this throughout the tape. The Nakamichi Dragon was one such tape deck and could be the best, if working well, for high quality playback.

If you want to transfer or convert a cassette to CD and adjust the azimuth yourself this is the an easy way to do it:

1. Look at the tape path (everything the tape will move across) and if it looks brown and dirty get some isopropyl alcohol and give it a good clean with a cotton bud.
2. If you haven’t demagnetised your deck for a while now would be a good time to do it..
3. Power up your cassette deck, which hopefully works correctly and doesn’t have too much speed instability!
4. Pop your tape in the cassette well and start to play.
5. Turn your amplifier’s volume up and if you can put it in Mono.
6. Now, look under the tape machine’s playback or combined record and playback heads you should see a small screw or nut possibly with anti tamper paint on it.
7. Using an appropriate tool, turn this nut or screw a little left or right while listening to the audio.
8. You should hear the recording, especially if it has a lot of high frequency content such as cymbals etc get bright and dull sounding or more technically get more in or out of phase.
9. Your aim is to get the most in phase or bright sounding playback.
10. Sounds better now?? Great, start to record using you favourite computer audio software. We like SoX for the control but there’s a huge range out there.

While some of our machines are serviced by others we like to regularly check them and have gradually bought our regular servicing in house. Of course this needs specialised tools, test tapes and gauges, often totally unavailable new now.

On a lucky eBay day I happened to win one of these beauties, an Information Terminals M-300 gauge. This enables you to accurately set the tape guide height and also the head stroke. It is a universal gauge and can be used across many decks.

Nakamichi tape deck owners have had a hard time doing this part of their servicing as the original Nakamichi gauges are very very rare now as is this.

A member of the naktalk mailing list though recently borrowed our gauge and has had it measured and will soon have a small batch CNC machined and made available. These remanufactured gauges will have a few small modifications to improve the design.

Thanks to Willy at www.willyhermansnervices.com many more tape deck transports will be able to be aligned correctly.