I've made a mix-tape of a band I've only heard on CD and mp3, and was listening to it last night. When it went to the other side, it sounded pretty bad. I manually changed the sides and it sounded much better. Is this a general fault with the auto-reverse? It doesn't sound quite as good playing backwards?

It usually caused when the head wear down over time, causing the head amuzith, to go off alignment on one side. Reason why don't like autoreverse decks. Go with a good three head single well deck with 2-3 motors. Best brands are nakamichi, even the two heads decks are pretty go and built like a tank and sometime can find cheap. Then you have higher end Sony ES series, but be careful when buying these as Sony design theses to keep the capston motor running when deck is power on and alot of people kept these tapedecks power on with their receiver, so you see alot with a bad capston motor, or worn bearings. Some of the higher end Pioneers are pretty good like the Pioneer Elite ct-93, consider to be the world best tapedeck, but comes at a price.

You can realign the head, but don't know how many hours is on your deck, head maybe worn badly. You need to adjust the screws their normally holes thur the tapedeck door where the head is located.

Personally I think it is more like :

Autoreverse = potential for badly aligned tape

Over the years manufacturers have made many autoreverse systems. Depending on the type of autoreverse system, your tape alignment may stand a better chance of being correct.

Fixed head

This is where the manufacturer has designed the head assembly in such a way that once pieced together it is roughly in alignment in both directions. So long as the tape being played is aligned to the same azimuth as the head, then both sides will play in alignment in theory. However in practice, slight differences in tolerance when the heads are manufactured means that heads can be ever so out of slight alignment. This is particularly noticeable when playing back Dolby C NR which requires critical tape alignment. This system is quite common on later autoreverse walkmans due to the more simplistic design and lower production costs.

Sony took the design of a fixed head further with a dual head design. Separate fixed azimuth heads are implemented for each direction of playback. You could argue this was a gimmick more than anything else, as there was no way of azimuth adjustment once it had left the factory.

As Retrodos previously mentioned, with head wear this problem can be made even worse. However with the fixed head design there is no easy way of correcting mis-alignment.

Manually adjustable head

This is where the head is screwed onto the head assembly with screws and is spring loaded at one side to pivot on the other. Head alighment is performed at the factory during assembly and the screws locked into place with threadlock glue. Normally seen on older walkman designs and some full sized decks.

Sometimes during the life of the unit the glue fails and alignment can drift. Re-adjusting the screw and applying new threadlock glue will usually restore playback alignment.

Sometimes head wear can affect playback and no amount of adjustment can correct the difference in alignment, but at least a compromise in alignment can be struck between the two directions unlike the fixed head design previously.

Bi-directional alignment

To offer even more precise alignment manufacturers introduced systems where alignment could be set independant of the opposing direction of playback. Therefore even if there were slight imperfections as seen from the manually adjustable head, this system would be able to correct it.

This is generally seen on 'better' auto reverse cassette decks, but some walkman manufacturers also adopted their own compact versions too.

For walkmans, the most famous of them all was AIWA with its bi-azimuth system. The bi-azimuth system was essentially an enhancement of the manually adjustable head and alignment would be governed by the positioning determined by pressure plates. However this feature was shortlived and was eventually replaced with the fixed head design.

Yes the problem is that it is difficult to maintain the correct Azimuth on Auto-Reverse decks, this is why most good quality decks only play in one direction.

The read head gap is microns wide and is critical to get the alignment correct for correct information retrieval.

Some decks try to fix this problem by having only a 2 channel head which is aligned to the forward direction, then when it needs to play the reverse direction the head physically rotates to the other side. This still did not work properly.

Nakamichi made the RX range of decks which they called Unidirectional Auto-Reverse decks, really what this deck did was to physically open the tape compartment door and flip the tape around for you. This way it kept the tape aligned to the correct Azimuth. See attached vid.

The only Auto-Reverse deck they made was the Dragon, which actually moved the head around when the sides changed. By the head moving they got the correct Azimuth. The only annoying thing about this method was when it hunted around for the best position you can hear it doing it.

LOL - yes completely forgot about the cassette flipper.

not a lover of auto reverse on some decks the sound of clunking is like droping a hammer in a empty dustbin

 used to make some home & system deckswhich had optical sensors to detect the leader tape & flip the head 'round very fast. They claimed a 0.2sec gap in playback when auto-reversing.

Not sure that was ever on a portable though...

as a rule on home decks - you never buy an AR (except the Nak Dragon)
Walkmen are no different - hence why the DC2 is the best walkman over the DD9

The DC2 is better than the DD9 because of the line-out socket so that you can connect to a home amplifier or use it to convert cassettes to computer. It also has 3V instead of 1.5V so that it gives better sound quality (higher output).

PS: Sorry for late reply. A static 4 track head is better than a 2 track head that flips.

There is also an auto reverse method that the head moves in height, similar to 8-tracks. It would have 3 positions, one in the middle for stop, two in forward play and three in reverse play.

There is one walkman that I know that used this method. Panasonic RQ-SW5V. It is less likely to suffer azimuth misalignment caused by moving the head around although I think it can suffer from crosstalk due to the method of what 8-track recorders use (hence the 8-tracks weakness for bad sound quality).

Sources:

Website:  http://www.apolloelectronics.c..._magneticheads.htm#3

Shift Type Auto Reverse Cassette Stereo Heads
AP-4226

The Sony Walkman that used the dual heads similar to TOTL reel to reel decks are difficult to use with cassettes because of the position of the FWD head. It does not contact the pressure pad. Whereas the REV head contacts the play head, therefore the sound is amplified. Unless the FWD head uses a pressure pad lifter, like Nakamichis, the sound is not going to be realized in the FWD direction.

Exactly "as long as the head is in 90 degrees". Cheaper fixed head units are simply put together at the factory and assumed the metal head is mounted correctly to the plastic mount when bonded with epoxy glue. However as they are cheap units or have poor quality control at the factory and as an example they may be set 88 degrees at FWD and 92 degrees at REV direction. Relative to each direction on the head it is "perfectly aligned", but not to the tape AND as it is a fixed head design you have no way to correct the +- 2 degree deviation.

There could be also zenith issues as well, and as a fixed head design this will not be correctable either.

There is indeed a pressure pad for the second head to correctly contact the tape. Still a cheap system. Heads are fixed on the dual head Sony Walkman, and thus non-adjustable. Also they are mounted using plastic cheap parts.

Another similar design of this autoreverse mechanism with dual heads is the microcassette. Since they have two pressure pads and the capstan is in the middle, that mechanism is directly from an autoreverse microcassette deck. RetroDOS has one of his video: http://www.youtube.com/watch?v=jT8NpSflCbQ

Another good thing of this dual head is that if both heads are 90 degrees, you have a perfect aligned heads (just like with a 4-track head) without the small crosstalk with 4-track heads where you can hear the right channel faintly from either directions. This does not affect the recordings from a recorder, only on play mode.

You said that the dual heads on the Sony are fixed? Well I see some springs pressed on screws on the head mounts on both of them. Here is an image of a Sony WM-EX999. The tape guides are plastic though.