dummy cassettes , why are the 2 spools connected

dohouch

Be surpised if I get an answer to this, but sometimes writing out the question actually results in onself coming up with the answer. I'm talking about those cassettes that are used if you want to connect, discman maybe IPOD too to a car cassette player. They have a unit that sits opposite the magnetic head of the cassette player and this transfers the signal to the car unit. All O.K.

My question , Why are the 2 spools of the dummy cassette connected by a series of gear wheels (cogs)
I have an mp3 discman and these dummy cassettes generate a rattle or rubbing noise which is quite annoying.

Why do the 2 spools have to be connectected in this way? This problem has been intruiging me for too long now. Have thought of going to Google answers and paying for an answer. The wather is so bad today I eventually got to stting down and typing it out.

dal

I am not too sure why this is, but i can tell you that I have taken the cogs out before just in order to get the thing to work on certain players. The fancy electronic players would tend to spit out the cassette, but removing the cogs solved this (I think it might have been something to do with the tension in the spools, caused by the cogs).

I think you could take them out if you didn't want that sound.

dohouch

Posted my question on another forum and got two replies:

1. There would be a risk of the the drive belt snapping if the two spools weren't connected.

2. Some players have a motion sensing system, led sensor, and won't play if the spool movement is not detected.

Also got a tip, use some light white grease, Slick 50 or Easy Grease. Haven't got around to getting either of these yet

mukki

older ones used to check the tension on the cassette's "tape" to see if it has reached the end
but they needed this tensioners location to implement auto-reverse

auto reverse "cassette" players check for rotation in the "non driven" spool to see if its reached the end