PL12D - Fine Tuning

[JulesBadass]

I have a Pioneer PL12D with a Shure M97xE.

Been playing with alignment to eliminate inner groove distortion, based on some great advice sourced on here and links therein, some specifically aimed at my cartridge which was ideal.

The IGD was fairly noticable before, so on the advice a read somewhere I introduced a little twst in the alignment, rather than having the cart square in the headshell.

This has made a huge difference (for the better). If you view he headshell from directly above, the cart retaining screws centres are probably about 1mm offset.

All that said, there is still a trace of IGD - usualy story, slightly ssshhhhy esses (but way less than before). Tried several records, and it's consistent accross them all.

My instinct is to give it a little more offset in the same direction. Is it ok to add more than i already have? Any danger of damaging the records or stylus by doing this too far?

Im happy the weight and anti-skate are good.

Any advice appreciated as always.

 

[gregory]

Hello, it's the stylus that needs to line up with the protractor,
not the cartridge so it looks like your going in the right direction, it can depend on what protractor you are using but a quick look on vinyl engine will reap great rewards, they have downloadable protractors and a pioneer forum so you will find
most answers there. Good luck.

 

[JulesBadass]

Thanks Gregory.

Yeah, that's where I sourced most of my understanding from.

That's a great point you make there - about it being the stylus not the cartridge which needs to line up.

The reason I pick up on this, is that I notice then when I lower the arm onto the record, as the stylus takes the weight of the arm, it doesn't continue downwards on the same vertical pane; the arm moves very slightly to the right, effectively "bending" the stylus cantilever in one direction - I guess this is the source of my needing to twist the cart mount, to compensate for this.

Is something bent somewhere? One corner of the suspension has a slight sag in it... to the rigth of the arm, which is consistant with the direction the cantilever bends towards. I wonder if this is the cause?

Thanks

 

[nopiano]

... I notice then when I lower the arm onto the record, as the stylus takes the weight of the arm, it doesn't continue downwards on the same vertical pane; the arm moves very slightly to the right, effectively "bending" the stylus cantilever in one direction - I guess this is the source of my needing to twist the cart mount, to compensate for this. Is something bent somewhere? One corner of the suspension has a slight sag in it... to the rigth of the arm, which is consistant with the direction the cantilever bends towards. I wonder if this is the cause? Thanks

Have you got enough anti-skate dialled in? And is it even working properly after 30-odd years? This will also affect end of side distortion, which you should aim to hear equally in each channel.

Also, have you tried removing the little rider weight, notionally designed to even up the bearing load, as it wll reduce the moving mass - as long as you rebalance the arm before playing it.

Lastly, if there is any sagging make sure the platter not the plinth in dead level, with your sprit level. I recall all those years ago I used pennies to level the TT under each foot.

 

[JulesBadass]

Yeah - fairly happy the anti si working well and setup reasonably. If I leave the arm in mid air and dial the anti skate to each extreme, the arm will swing in either direction. The deck was rescued from a market, but seems to have been looked after - lid un scuffed and no cracks, holds a solid speed and everything works nicely. I've replaced the belt and cart.

It's just the sag on one corner (bottom right as) of the suspended plinth, which is the direction the arm sways towards when it takes up the strain. I will try and prop it up on that corner and see if the sway to the right reduces - which ought to eliminate somethign else being bent somehow.

I understand there are known problems with deterioration of the springs/dampers on these, and that the dampers can be replaces with bits of foam... sounds like what has happened here. However, I'm unsure on the best way to dismantle it and lift the suspended plinth to get at the springs.

 

[altruistic.lemon]

Mate, spend a few quid and get yourself a test record. Scales - Ortofon or Shure, they're inexpensive - are also a good idea. Also, Set the VTF at the high end of the manufacturer's specs, and make sure the turntable is dead level.

 

[JulesBadass]

Yeah - i didn't realise what the test record was all about until last week when I saw a demo on you tube. I've got some slim jewelary scales, and the weight is good; currently set at the upper end of the brush-down reccomendation, 2g, as you suggest.

Im gonna try to lever up the suspended platter to be level, relevel the entire unit (I've currently used business cards under the feet), check that the platter is level accross all angles, then recheck this issue Im seeing where the arm drops off to one side.

To simulate what's happening, if you hold your finger in the air at head height, then scribe a straight line down to your lap, then just before you touch you legs, veer your line diagonally to the right, that is what my tone arm does when you lower it onto the platter using the leaver. From the top: it drops perpendicular to the record, then the stylus tip hits the record - all good, then when you release the last little but of movement from the leaver and the strain is taken up fully by the stylus, the movement veers off being perpendicular, and falls very slightly to the right.

If it's not a leveling issue that's causing this, what else could it be? As I write this, it does seem to point at too much anti skate... the arm is biasing away from the spindle. I'll have a play in both of these areas.

Failing both of these - maybe a bearing issue in the tone arm??

 

[JulesBadass]

Bit of an update.

Played around with getting the level correct accross the path where the stylus tracks (involved propping up one corner of the plinth to compensate for the sagging suspension) - definately better.

During testing, I've discovered some records are completely fine on the inner grooves, others sound rough. Most of my vinyl is 2nd hand so I put this down to the reorcds themselves, either having been played on a badly adjusted setup, or a bad pressing. Either way, encouraging that it plays well with certain records.

So - in short, some things to do:

> Get the bonnet up and replace the damping foam in the suspension

> Restore the motor rubbers. There is also a reasonable amount of hum from the motor. I thought this was normal, however from other PL12d owners on VinylEngine, it seems to be a common problem that can be erradicated.

Cheers.