Technics tonearm issue.

Hi guys,

Having a problem with one of my 1210's... I'm pretty sure it's a tone-arm issue. Basically on records with large bass-lines / deep grooves, one of my Technics will produce an ugly muddy bass, as if the stylus isn't properly sitting in the groove. Both of my decks have IDENTICAL set-ups: identical height, weight, anti-skate; identical needles, slipmats, hardware etc-- it's all the same, as a control. I've swapped the needles around multiple times to cancel out the possibility of it being a cart/stylus problem.

So I'm guessing the only thing it can be is my tone-arm... but this is the one part of a table I know next to nothing about, nor how to fix it. I'm guessing it's something to do with its tightness, or the bearings? I've taken two videos anyway, so you can clearly see what is going wrong.

http://www.youtube.com/watch?v=527sTsiREYE

In the beginning of this video you see my first deck (the fine one), and the large bass line plays fine, without any nasty audio problems. The tone-arm and needle handles it great. (And yes, I know my speaker set-up is hardly ideal at the moment... this is changing on the weekend, and besides, it's clear that this is an isolated and specific problem with the second deck).

http://www.youtube.com/watch?v=QBCK8RSiP-k&f

More detail in this one, especially when the platter is rotating slowly. You can very clearly see that the entire tone-arm shakes, wobbles, and vibrates when playing the deeper/wider grooves (i.e. the bassy parts). So much so in fact that it basically skips along the record at a low speed. You can see it very clearly in action on certain 3-4 second segments of the above video.

So, in short: how do I fix this? I'm hoping it's not a serious problem with the tone-arm assembly or bearings. I know there's a horizontal and vertical screw to be tightened on the tone-arm, but after gently changing both (both clockwise and anti-clockwise), I don't see much difference.

Cheers!

Just to rule out it being something defective with the record, here's another deep bass one...

The tone-arm/stylus is basically getting speed wobbles! It's not so noticeable at 45rpm but the bass clarity still suffers a LOT.

http://www.youtube.com/watch?v=kH1ufKRYqd8

From 20 secs onward in this vid, even though the iPhone focus is poor, you can see the actual entire tone-arm 'wobbling' from side-to-side.

tone-arm screws/bearings are tricky. all three have to be evenly spaced out to pivot the tonearm and the top one cannot be over tight... adjusting them will fix your wobble issue BUT as far as the sound is concerned you may need to replace rca's which require soldering... you can use a drimmel and some aluminum cleaner to clean the contacts before we assume that option....there is a you tube video on how to do so

Thanks for your reply buddy - I just opted to replace the entire tone-arm assembly in the end. I think the verticle-axis bearings had gone, which was causing a major problem. I did a series of 'tone arm tests' using the anti-skate and it was clear that something in the bearings wasn't working properly; the tone-arm was constantly wanting to drift out towards the edge of the platter, being dragged quite severely, which was obviously wearing out my records and causing skips on bassy songs. £40 to replace the entire tone-arm... should have it all fitted and soldered this week.

On another note: my left cartridge outputs unevenly over the left/right channel by about 1.5dB. I know this is often a contact issue in the headshell/cartridge. Does anyone have any recommendations for cleaning the contacts inside the end of a tone-arm/cartridge? How to get the best contact and therefore the cleanest output/results? Will aluminium cleaner do the same job, here? The small difference isn't that much, just it drives me crazy knowing that one of my cartridges technically outputs better than the other! Cheers.

Sometimes carts are just "different" than each other, majority of times with uneven levels its the stylus than is the issue, I take it you have swapped to check though ?

A Ciggie Butt (unsmoked) inserted and spun around a few times in the tonearm is handy, they are gold plated so shoudn't need any more than a dry wipe.