Breaking in drive belts; pickup cartridges etc.

[Circlotron]

Yesterday I dug out my ancient Teac V-9 cassette deck to transfer a speech recording to hard-disk for a bit of de-noising etc. Anyway, the flat drive belt that goes around the periphery of the ~60mmx25mm flywheel had lost all it's tension. I looked around for something to replace it and ended up using an ordinary 6mm wide rubber band.

Then I thought, with all this talk lately about about breaking-in / burning-in stuff, I have never heard of anyone having to break in a drive belt or idler wheel or pinch roller. Or what about a pickup cartridge? Does the suspension soften up with a bit of use? And how long does it take to break in a listening room?..

[SY]

The suspensions of pickups absolutely do change with use. They also change with temperature, humidity, and exposure to various things in the atmosphere. The changes are easily measurable and exceed the threshold for aural detection. Call it "break-in," call it "aging," whatever, it's one more reason that a phonograph is not a reliably accurate signal source.

[mrfeedback]

Hi Graham,
In my experience belts 'break-out".
The rubber that they are made of can go soft and even gooey and thereby loses tension.
When a belt is not used for a time, it may also take a 'set' to the position that it has been stored in and this can cause a wow/flutter component.
WES components have a full range of belts, and cheap.
Before fitting the new belt, polish running surfaces (pulley and flywheel) with brasso to remove any roughness or adhering rubber particles.

Eric.

[fdegrove]

Hi,

Call it "break-in," call it "aging," whatever, it's one more reason that a phonograph is not a reliably accurate signal source.

Digital replay systems can suffer from similar setbacks just the same.

As far as cartridge suspensions go, natural rubber suspensions seems to be less prone to wear and tear and other natural elements.

Tape recorders or other devices using rubber belts should have their belts removed, treated with talkum powder and stored in a neutral environment away from direct sunlight when not used for a prolonged period of time.

Cheers,

[SY]

Natural rubber suffers from compression set, from extreme variation with temperature and use, and rapid deterioration when exposed to typical urban pollutants. With most phono cartridges, the suspension deteriorates long before the stylus itself.

I haven't found a D/A that ages as badly, or at all, for that matter, though I certainly have not tried them all. Maybe the bits just fall out with repeated toggling?

[fdegrove]

Hi,

Natural rubber suffers from compression set, from extreme variation with temperature and use, and rapid deterioration when exposed to typical urban pollutants.

As do most elastomers.

However, it is my experience and not only mine, that natural rubber is the best for use in a MC cartridge.

Witness my excellent Jan Allaerts cartridge which is the only MC I've ever used where the suspension outlasts the stylus tip by a considerable margin.

I haven't found a D/A that ages as badly, or at all, for that matter, though I certainly have not tried them all. Maybe the bits just fall out with repeated toggling?

Not the D/A convertor but the CDP itself uses belts to position the laser on the disc.
People usually don't keep them long enough to notice the error correction working harder over time.

The pink-brown ring on the right is the suspension made out of natural rubber.

Cheers,

[fdegrove]

Hi,

In all fairness I should add that the rubber used in that cartridge is high-tech rubber of a 100 Schor.

Not something you'd find in your average cartridge of course.

Cheers,

[wintermute]

Hi Circlotron,

the thing I would be worried about is that your rubber band doesn't have too much tension. If it does you may end up wearing out bearings and possibly put more strain on the motor. probably best to try and get an original belt if possoible.

Regards,

Tony.

[Circlotron]

Hi Tony and everyone else.
The belt tension is about 150 grams at a guess. A bit higher than the original but still within reason I think. I hardly ever use this thing nowadays so it ought to last for a long time. Only thing is, the thickness of the belt (rubber band) varies by +50% over it's length so that would not help the speed to be pefectly steady, but on speech I cannot hear any problem. I'll record a steady tone sometime to see if there is any worthwile wow and flutter. Then I can stress out over a problem I didn't know I had.

[wintermute]

<grin> Glad to see I'm not the only one to suffer from the "I never realised there was a problem, but now I know I have to find a way to fix it" syndrome

Regards,

Tony.

PS. I was going on experience with car belts (fan belts etc) for the wearing of bearings, so if you are only using occasionally and the diff in tension is mimimal then I suspect your right and you won't have any problems.