vinyl tracking (or rather, not tracking) question

hi
tried to play billy bragg vinyl ep last night - the one with "new england" on it, mind has gone blank on the title.

anyway, looks mint, gave it a quick brush round, runs at 45rpm.

cued up and the arm bounced around on the first tracks of both sides.
so i double checked the downforce with my shure gauge, reset it to as close to 1.5 grammes as i could get it.

tried again, same thing.

seems to play for a couple of revolutions, then gets thrown back to the start again. nothing noticeable - scratch, fluff etc - to cause that. vinyl appears to be completely flat, so it's not being thrown off by a warp.
half-way tracks there was a noticeable bounce but not enough to throw the needle off. inner tracks played fine.

antiskate mechanism is set at the lowest setting.

then i got paged and had to work, so didn't get the opportunity to try another 12" 45rpm - though i have a few and never had a problem before. so will try another 1 or 2 tonight

could this just be a bad pressing ? like the groove isn't deep enough for the needle to sit in it, or something ?

thanks for your help. guys.

 

I've had this problem before and only with duff pressings. Even a top cart may jump out of the grooves of certain LPs due to pisspoor pressing quality...my copy of DJ Shadow's "Entroducing" is quite bad for this. Even my Koetsu doesn't change things....best advice is to try and find a better pressing.

 

Presumably that'll be "Life's a Riot with Spy Vs Spy" (orange and white cover with a lamp on the front) - I was 16 when it came out and it was in constant rotation for about a year. An all time favourite.

Back to the problem - could be a duff pressing. If it is, then you ought to seek out another copy. Its a classic. But remember - Pay no more than £2.99!!

 

Increase the bias setting, this should work.


KXF

 

bias is set as low as it will go - this is what kevin @ definitive advised. in fact he went one stage further -> to suggest i should remove the little weight completely.

 

I did that on my Kuzma unipivot Robert.

It was so amazingly sensitive, only removing the weight in its entirety completley removed skipping.

Its worked 100% as required ever since.

definately something I'd reccomend trying. Id bet it will work for you too.

 

Which way is the arm skipping, inwards or outwards?

 

Actually having read this further and realised you have a spcae arm, the guys may be right. When you say you have the bias set as low as it will go I'm assuming you mean its as close to its pivot as it will go?

What weight is the grado tracking at? I had a Shure V15 (til I trashed it) on my Spacearm - trying to track it in the middle of its recommended range at 1g, it wasn't happy bias wise - simply couldn't get it low enough, even with the weight removed entirely - drop the needle and you could see the arm drift out toward the edge. at 1.25g it'd work but again it was with the weight entirely removed.

Now I'm using a Denon DL-160 and tracking that at 1.7g ... I have the opposite problem and need more weight on the bias arm than the supplied weight has - I've remedied temporarily with blutac and it works just fine - intend to get an extra weight from NAS. So it seems the spacearm is a)very sensitive re bias and b) with none to a single weight has a fairly narrow range it'll work within and c) there is a minimum combo of tracking force/cart weight below which it won't go - even without the weight, the arm itself has some weight and so can't be completely disabled..

As an aside. Do you have the blank record style dust cover supplied with NAS decks? If so, it can be quite handy for setting bias. Make sure its clean and polished and place it upside down on the platter. Gently lower the stylus onto the surface and gently rotate the platter clockwise. With bias set correctly it should stay where it is - if it drifts in or out, adjust bias. Seems to work.

 

yep, the bias weight is close to the pivot. tracking weight is 1.5g.
i think with this record the arm is thrown outwards, rather than inwards - but then it kind of bounces around, probably because it's just been thrown and cant find a hold anymore, and then i quickly raise it.

NB this is the only record i've had trouble with, everything else plays just fine.

i'll try removing the bias weight completely and see what happens ......

 

Other thing to check is that the counterweight is pretty much vertical - I discovered that having it twisted (which you might want to do to set azimuth) - also affects bias and VTF.

So if looking down the arm from the front, the counterweight is hanging out to the left it has the effect of much reducing bias and lowering VTF (I think from memory but it may be the other way round). If it hangs out to the right it increases bias and lowers VTF. I was having real nightmares trying to juggle all these parameters and left it hanging vertical, azimuth be damned (its not far off anyway).